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Michael Bloomberg

Michael Rubens Bloomberg (born February 14, 1942) is an American businessman and politician. He is the majority owner and co-founder of Bloomberg L.P., and was its CEO from 1981 to 2001 and again from 2014 to 2023. He served as the mayor of New York City for three terms from 2002 to 2013 and was a candidate for the 2020 Democratic nomination for president of the United States. In 2024, Bloomberg received the Presidential Medal of Freedom from President Joe Biden. He has served as chair of the Defense Innovation Board, an independent advisory board that provides recommendations on artificial intelligence, software, data and digital modernization to the United States Department of Defense, since June 2022.

Bloomberg grew up in Medford, Massachusetts, and graduated from Johns Hopkins University and Harvard Business School. He began his career at the securities brokerage firm Salomon Brothers before forming his own company in 1981. That company, Bloomberg L.P., is a financial information, software and media firm that is known for its Bloomberg Terminal. Bloomberg spent the next twenty years as its chairman and CEO. As of April 2024, Forbes ranked him as the thirteenth-richest person in the world, with an estimated net worth of US$106.2 billion. Bloomberg, who has signed The Giving Pledge, has given away $17.4 billion to philanthropic causes in his lifetime.

Bloomberg was elected the 108th mayor of New York City in 2001. He held office for three consecutive terms, winning re-election in 2005 and 2009. Pursuing socially liberal and fiscally moderate policies, Bloomberg developed a technocratic managerial style.

As the mayor of New York, Bloomberg established public charter schools, rebuilt urban infrastructure, and supported gun control, public health initiatives, and environmental protections. He also led a rezoning of large areas of the city, which facilitated massive and widespread new commercial and residential construction after the September 11 attacks. Bloomberg is considered to have had far-reaching influence on the politics, business sector, and culture of New York City during his three terms as mayor. He has also faced significant criticism for the city's stop and frisk program, support for which he reversed with an apology before his 2020 presidential run.

After a brief stint as a full-time philanthropist, he re-assumed the position of CEO at Bloomberg L.P. by the end of 2014. In November 2019, four months before Super Tuesday, Bloomberg officially launched his campaign for the Democratic nomination for president of the United States in the 2020 election. He ended his campaign in March 2020, after having won only 61 delegates. Bloomberg self-funded $935 million for his candidacy, which set the record for the most expensive U.S. presidential primary campaign.

Early life and education
Bloomberg was born on February 14, 1942, at St. Elizabeth's Hospital, in the Brighton neighborhood of Boston, to William Henry Bloomberg (1906–1963), a bookkeeper for a dairy company, and Charlotte (née Rubens) Bloomberg (1909–2011). His father never earned more than $6,000 a year. William Henry Bloomberg died suddenly when his son was in college. The Bloomberg Center at the Harvard Business School was named in William Henry's honor. Bloomberg's family is Jewish, and he is a member of the Temple Emanu-El in Manhattan. Bloomberg's paternal grandfather, Rabbi Alexander "Elick" Bloomberg, was a Polish Jew. Bloomberg's maternal grandfather, Max Rubens, was a Lithuanian Jewish immigrant from present-day Belarus, and his maternal grandmother was born in New York to Lithuanian Jewish parents.

The family lived in Allston until Bloomberg was two years old, followed by Brookline, Massachusetts, for two years, finally settling in the Boston suburb of Medford, Massachusetts, where he lived until after he graduated from college.

Bloomberg became an Eagle Scout when he was twelve years old. He graduated from Medford High School in 1960. He went on to attend Johns Hopkins University, where he joined the fraternity Phi Kappa Psi. While there, he constructed the blue jay costume for the university's mascot. He graduated in 1964 with a Bachelor of Science degree in electrical engineering. In 1966, he graduated from Harvard Business School with a Master of Business Administration (MBA) degree.

Bloomberg is a member of Kappa Beta Phi and Tau Beta Pi. He wrote an autobiography, Bloomberg by Bloomberg, with help from Bloomberg News editor-in-chief Matthew Winkler.

Business career

In 1966, Bloomberg was hired for a job earning $9,000 per year at Salomon Brothers, a large Wall Street investment bank. Salomon Brothers later promoted him to the equities desk. Bloomberg became a general partner at Salomon Brothers in 1972; he headed equity trading and, later, systems development. Phibro Corporation bought Salomon Brothers in 1981, and the new management fired Bloomberg, paying him $10 million for his equity in the firm.

Using the money he received from Phibro, Bloomberg—having designed in-house computerized financial systems for Salomon—set up a data services company named Innovative Market Systems (IMS) based on his belief that Wall Street would pay a premium for high-quality business information, delivered instantaneously on computer terminals in a variety of usable formats. The company sold customized computer terminals that delivered real-time market data, financial calculations and other analytics to Wall Street firms. The terminal, first called the Market Master terminal, was released to market in December 1982.

In 1986, IMS renamed itself Bloomberg L.P. Over the years, ancillary products including Bloomberg News, Bloomberg Radio, Bloomberg Message, and Bloomberg Tradebook were launched. Bloomberg, L.P. had revenues of approximately $10 billion in 2018. As of 2019, the company has more than 325,000 terminal subscribers worldwide and employs 20,000 people in dozens of locations.

The culture of the company in the 1980s and 1990s has been compared to a fraternity, with employees bragging in the company's office about their sexual exploits. The company was sued four times by female employees for sexual harassment, including one incident in which a victim claimed to have been raped. To celebrate Bloomberg's 48th birthday, colleagues published a pamphlet entitled Portable Bloomberg: The Wit and Wisdom of Michael Bloomberg. Among various sayings that were attributed to him, several have subsequently been criticized as sexist or misogynistic.

When he left the position of CEO to pursue a political career as the mayor of New York City, Bloomberg was replaced by Lex Fenwick and later by Daniel L. Doctoroff, after his initial service as deputy mayor under Bloomberg. After completing his final term as the mayor of New York City, Bloomberg spent his first eight months out of office as a full-time philanthropist. In fall 2014, he announced that he would return to Bloomberg L.P. as CEO at the end of 2014, succeeding Doctoroff, who had led the company since February 2008. Bloomberg resigned as CEO of Bloomberg L.P. to run for president in 2019.

In January 2024, John P. Angelos reached a $1.725 billion deal to sell the Baltimore Orioles to a group led by David Rubenstein. The group included Bloomberg, former Baltimore Mayor Kurt Schmoke, Cal Ripken, New York investment manager Michael Arougheti and NBA legend Grant Hill.

Wealth
In March 2009, Forbes reported Bloomberg's wealth at $16 billion, a gain of $4.5 billion over the previous year, the world's biggest increase in wealth from 2008 to 2009. Bloomberg moved from 142nd to 17th in the Forbes list of the world's billionaires in only two years. In the 2019 Forbes list of the world's billionaires, he was the ninth-richest person; his net worth was estimated at $55.5 billion. Currently, Bloomberg's net worth is estimated at $106 billion, ranking him 12th on Forbes' list of billionaires.

Mayor of New York City

Bloomberg assumed office as the 108th mayor of New York City on January 1, 2002. He won re-election in 2005 and again in 2009. As mayor, he initially struggled with approval ratings as low as 24 percent; however, he subsequently developed and maintained high approval ratings. Bloomberg joined Rudy Giuliani, John Lindsay, and Fiorello La Guardia as re-elected Republican mayors in the mostly Democratic city.

Bloomberg stated that he wanted public education reform to be the legacy of his first term and addressing poverty to be the legacy of his second.

Bloomberg chose to apply a statistical, metrics-based management approach to city government, and granted departmental commissioners' broad autonomy in their decision-making. Breaking with 190 years of tradition, he implemented what New York Times political reporter Adam Nagourney called a "bullpen" open office plan, similar to a Wall Street trading floor, in which dozens of aides and managerial staff are seated together in a large chamber. The design is intended to promote accountability and accessibility.

Bloomberg accepted a remuneration of $1 annually in lieu of the mayoral salary.

As mayor, Bloomberg turned the city's $6 billion budget deficit into a $3 billion surplus, largely by raising property taxes. Bloomberg increased city funding for the new development of affordable housing through a plan that created and preserved an estimated 160,000 affordable homes in the city. In 2003, he implemented a successful smoking ban in all indoor workplaces, including bars and restaurants, and many other cities and states followed suit. On December 5, 2006, New York City became the first city in the United States to ban trans-fat from all restaurants. This went into effect in July 2008 and has since been adopted in many other cities and countries. Bloomberg created bicycle lanes, required chain restaurants to post calorie counts, and pedestrianized much of Times Square. In 2011, Bloomberg launched the NYC Young Men's Initiative, a $127 million initiative to support programs and policies designed to address disparities between young Black and Latino men and their peers, and personally donated $30 million to the project. In 2010, Bloomberg supported the then-controversial Islamic complex near Ground Zero.

Under the Bloomberg Administration, the New York City Police Department greatly expanded its stop and frisk program, with a sixfold increase in documented stops. The policy was challenged in U.S. Federal Court, which ruled that the city's implementation of the policy violated citizens' rights under the Fourth Amendment of the Constitution and encouraged racial profiling. Bloomberg's administration appealed the ruling; however, his successor, Mayor Bill de Blasio, dropped the appeal and allowed the ruling to take effect. After the September 11 attacks, with assistance from the Central Intelligence Agency, Bloomberg's administration oversaw a controversial program that surveilled Muslim communities on the basis of their religion, ethnicity, and language. The program was discontinued in 2014.

In a January 2014 Quinnipiac poll, 64 percent of voters called Bloomberg's 12 years as mayor "mainly a success".

2001 election
In 2001, New York's Republican mayor Rudy Giuliani, was ineligible for re-election due to the city's limit of two consecutive terms. Bloomberg, who had been a lifelong member of the Democratic Party, decided to run for mayor on the Republican ticket. Voting in the primary began on the morning of September 11, 2001. The primary was postponed later that day, due to the September 11 attacks. In the rescheduled primary, Bloomberg defeated Herman Badillo, a former Democratic congressman, to become the Republican nominee. After a runoff, the Democratic nomination went to New York City Public Advocate Mark Green.

Bloomberg received Giuliani's endorsement to succeed him in the 2001 election. He also had a huge campaign spending advantage. Although New York City's campaign finance law restricts the total amount of contributions that a candidate can accept, Bloomberg chose not to use public funds and therefore his campaign was not subject to these restrictions. He spent $73 million of his own money on his campaign, outspending Green by a ratio of five to one.

In the wake of the September 11 attacks, Bloomberg's administration made a successful bid to host the 2004 Republican National Convention. The convention drew thousands of protesters, among them New Yorkers against George W. Bush and the Bush administration's pursuit of the Iraq War.

2005 election
Bloomberg was re-elected mayor in November 2005 by a margin of 20 percent, the widest margin ever for a Republican mayor of New York City. He spent almost $78 million on his campaign, exceeding the record of $74 million he spent on the previous election. In late 2004 or early 2005, Bloomberg gave the Independence Party of New York $250,000 to fund a phone bank seeking to recruit volunteers for his re-election campaign.

Former Bronx Borough President Fernando Ferrer won the Democratic nomination to oppose Bloomberg in the general election. Thomas Ognibene sought to run against Bloomberg in the Republican Party's primary election. The Bloomberg campaign successfully challenged the signatures Ognibene submitted to the Board of Elections to prevent Ognibene from appearing on ballots for the Republican primary. Instead, Ognibene ran on only the Conservative Party ticket. Ognibene accused Bloomberg of betraying Republican Party ideals, a feeling echoed by others.

Bloomberg opposed the confirmation of John Roberts as Chief Justice of the United States. Bloomberg is a staunch supporter of abortion rights and did not believe that Roberts was committed to maintaining Roe v. Wade. In addition to Republican support, Bloomberg obtained the endorsements of several prominent Democrats: former Democratic mayor Ed Koch; former Democratic governor Hugh Carey; former Democratic City Council Speaker Peter Vallone, and his son, Councilman Peter Vallone Jr.; former Democratic Congressman Floyd Flake (who had previously endorsed Bloomberg in 2001), and Brooklyn Borough President Marty Markowitz.

2009 election

On October 2, 2008, Bloomberg announced he would seek to extend the city's term limits law and run for a third mayoral term in 2009. Bloomberg said, "Handling this financial crisis while strengthening essential services ... is a challenge I want to take on," Bloomberg said at a news conference. "So should the City Council vote to amend term limits, I plan to ask New Yorkers to look at my record of independent leadership and then decide if I have earned another term."

Ronald Lauder, who campaigned for New York City's term limits in 1993 and spent over 4 million dollars of his own money to limit the maximum years a mayor could serve to eight years, sided with Bloomberg and agreed to stay out of future legality issues. In exchange, he was promised a seat on an influential city board by Bloomberg.

Some people and organizations objected and NYPIRG filed a complaint with the City Conflict of Interest Board. On October 23, 2008, the city council voted 29–22 in favor of extending the term limit to three consecutive four-year terms. After two days of public hearings, Bloomberg signed the bill into law on November 3.

Bloomberg's bid for a third term generated some controversy. Civil libertarians such as former New York Civil Liberties Union Director Norman Siegel and New York Civil Rights Coalition Executive Director Michael Meyers joined with local politicians to protest the process as undermining the democratic process.

Bloomberg's opponent was Democratic and Working Families Party nominee Bill Thompson, who had been New York City Comptroller for the past eight years and before that, president of the New York City Board of Education. Bloomberg defeated Thompson by a vote of 51 percent to 46 percent. Bloomberg spent $109.2 million on his 2009 campaign, outspending Thompson by a margin of more than 11 to one.

After the release of Independence Party campaign filings in January 2010, it was reported that Bloomberg had made two $600,000 contributions from his personal account to the Independence Party on October 30 and November 2, 2009. The Independence Party then paid $750,000 of that money to Republican Party political operative John Haggerty Jr.

This prompted an investigation beginning in February 2010 by the office of New York County District Attorney Cyrus Vance Jr. into possible improprieties. The Independence Party later questioned how Haggerty spent the money, which was to go to poll-watchers. Former New York State Senator Martin Connor contended that because the Bloomberg donations were made to an Independence Party housekeeping account rather than to an account meant for current campaigns, this was a violation of campaign finance laws. Haggerty also spent money from a separate $200,000 donation from Bloomberg on office space.

2013 election
On September 13, 2013, Bloomberg announced that he would not endorse any of the candidates to succeed him. On his radio show, he stated, "I don't want to do anything that complicates it for the next mayor. And that's one of the reasons I've decided I'm just not going to make an endorsement in the race." He added, "I want to make sure that person is ready to succeed, to take what we've done and build on that."

Bloomberg praised The New York Times for its endorsement of Christine Quinn and Joe Lhota as their favorite candidates in the Democratic and Republican primaries, respectively. Quinn came in third in the Democratic primary and Lhota won the Republican primary. Bloomberg criticized Democratic mayoral candidate Bill de Blasio's campaign methods, which he initially called "racist"; Bloomberg later downplayed and partially retracted those remarks.

On January 1, 2014, de Blasio became New York City's new mayor, succeeding Bloomberg.

Post-mayoral political involvement
Bloomberg was frequently mentioned as a possible centrist candidate for the presidential elections in 2008 and 2012, as well as for governor of New York in 2010 or vice-president in 2008. He eventually declined to seek all of these offices.

In the immediate aftermath of Hurricane Sandy in November 2012, Bloomberg penned an op-ed officially endorsing Barack Obama for president, citing Obama's policies on climate change.

2016 elections

On January 23, 2016, it was reported that Bloomberg was again considering a presidential run, as an independent candidate in the 2016 election, if Bernie Sanders got the Democratic party nomination. This was the first time he had officially confirmed he was considering a run. Bloomberg supporters believed that Bloomberg could run as a centrist and capture many voters who were dissatisfied with the likely Democratic and Republican nominees. However, on March 7, Bloomberg announced he would not be running for president.

In July 2016, Bloomberg delivered a speech at the 2016 Democratic National Convention in which he called Hillary Clinton "the right choice". Bloomberg warned of the dangers a Donald Trump presidency would pose. He said Trump "wants you to believe that we can solve our biggest problems by deporting Mexicans and shutting out Muslims. He wants you to believe that erecting trade barriers will bring back good jobs. He's wrong on both counts." Bloomberg also said Trump's economic plans "would make it harder for small businesses to compete" and would "erode our influence in the world". Trump responded to the speech by condemning Bloomberg in a series of tweets.

2018 elections
In June 2018, Bloomberg pledged $80 million to support Democratic congressional candidates in the 2018 election, with the goal of flipping control of the Republican-controlled House to Democrats. In a statement, Bloomberg said that Republican House leadership were "absolutely feckless" and had failed to govern responsibly. Bloomberg advisor Howard Wolfson was chosen to lead the effort, which was to target mainly suburban districts. By early October, Bloomberg had committed more than $100 million to returning the House and Senate to Democratic power, fueling speculation about a presidential run in 2020. On October 10, 2018, Bloomberg announced that he had returned to the Democratic party.

2020 presidential campaign
On March 5, 2019, Bloomberg had announced that he would not run for president in 2020. Instead, he encouraged the Democratic Party to "nominate a Democrat who will be in the strongest position to defeat Donald Trump." However, due to his dissatisfaction with the Democratic field, Bloomberg reconsidered. He officially launched his campaign for the 2020 Democratic nomination on November 24, 2019.

Bloomberg self-funded his campaign from his personal fortune and did not accept campaign contributions.

Bloomberg's campaign suffered from his lackluster performance in two televised debates. When Bloomberg participated in his first presidential debate, Elizabeth Warren challenged him to release women from non-disclosure agreements relating to their allegations of sexual harassment at Bloomberg L.P. Two days later, Bloomberg announced that there were three women who had made complaints concerning him, and added that he would release any of the three if they request him to do so. Warren continued her attack in the second debate the next week. Others criticized Bloomberg for his wealth and campaign spending, as well as his former affiliation with the Republican Party.

As a late entrant to the race, Bloomberg skipped the first four state primaries and caucuses. He spent $676 million of his personal fortune on the primary campaign, breaking a record for the most money ever spent on a presidential primary campaign. His campaign blanketed the country with campaign advertisements on broadcast and cable television, the Internet, and radio, as well as direct mail. Bloomberg also spent heavily on campaign operations that grew to 200 field offices and more than 2,400 paid campaign staffers. His support in nationwide opinion polls never exceeded 15 percent but stagnated or dropped before Super Tuesday, while former vice president Joe Biden had become the frontrunner after receiving the support of major candidates Pete Buttigieg and Amy Klobuchar shortly before Super Tuesday. Bloomberg suspended his campaign on March 4, 2020, after a disappointing Super Tuesday in which he won only American Samoa, and subsequently endorsed Biden. Bloomberg donated $18 million to the Democratic National Committee and publicly planned a "massive spending blitz" to support Biden's campaign.

When a 60 Minutes correspondent remarked on March 1 that Bloomberg had spent twice what President Trump had raised, he was asked how much he would spend. Bloomberg replied, "I'm making an investment in this country. My investment is I'm going to remove President Trump from 1600 Pennsylvania Avenue or at least try as hard as I can."

Speaking on the final night of the 2020 Democratic National Convention, Bloomberg took aim at Trump's handling of the COVID-19 pandemic and the American economy: "Would you rehire or work for someone who ran your business into the ground? Who always does what's best for him or her, even when it hurts the company, and whose reckless decisions put you in danger, and who spends more time tweeting than working? If the answer is no, why the hell would we ever rehire Donald Trump for another four years?"

Defense Innovation Board
In February 2022, Bloomberg was nominated to chair the Defense Innovation Board, being sworn in on June 22, 2022.

Political positions

Bloomberg was a Democrat until 2001, when he switched to the Republican Party to run for mayor. He switched to an independent in 2007 and registered again as a Democrat in October 2018. In 2004, he endorsed the re-election of George W. Bush and spoke at the 2004 Republican National Convention. He endorsed Barack Obama's re-election in 2012, endorsed Hillary Clinton in the 2016 election, and spoke at the 2016 Democratic National Convention.

As Mayor of New York, Bloomberg supported government initiatives in public health and welfare. This included tobacco control efforts (including an increase in the legal age to purchase tobacco products, a ban on smoking in indoor workplaces, and an increase in the cigarette tax); the elimination of the use of artificial trans fats in restaurants; and bans on all flavored tobacco and e-cigarette products including menthol flavors. Bloomberg also launched an unsuccessful effort to ban on certain large (more than 16 fluid ounce) sugary sodas at restaurants and food service establishments in the city. These initiatives were supported by public health advocates but were criticized by some as "nanny state" policies.

Over his career, Bloomberg has "mingled support for progressive causes with more conservative positions on law enforcement, business regulation and school choice." Bloomberg supports gun-control measures, abortion rights, same-sex marriage, and a pathway to citizenship for illegal immigrants. He advocates for a public health insurance option that he has called "Medicare for all for people that are uncovered" rather than a universal single-payer healthcare system. He is concerned about climate change and has touted his mayoral efforts to reduce greenhouse gases. Bloomberg supported the Iraq War and opposed creating a timeline for withdrawing troops. Bloomberg has sometimes embraced the use of surveillance in efforts to deter crime and protect against terrorism.

During and after his tenure, he was a staunch supporter of stop-and-frisk. In November 2019, Bloomberg apologized for supporting it. He advocates reversing many of the Trump tax cuts. His own tax plan includes implementing a 5 percent surtax on incomes above $5 million a year and would raise federal revenue by $5 trillion over a decade. He opposes a wealth tax, saying that it would likely be found unconstitutional. He has also proposed more stringent financial regulations that include tougher oversight for big banks, a financial transactions tax, and stronger consumer protections. He supported decreasing estate-tax threshold to collect more estate taxes and close tax avoidance schemes. According to ProPublica investigation he set up multiple GRATs thus shielding parts of his fortune for his heirs.

Bloomberg stated that running as a Democrat – not an independent – was the only path he saw to defeating Donald Trump, saying: "In 2020, the great likelihood is that an independent would just split the anti-Trump vote and end up re-electing the President. That's a risk I refused to run in 2016 and we can't afford to run it now."

In the 2020 general election, Bloomberg invested $115 million in Joe Biden's campaign in key states like Florida, Ohio, and Texas, contributed millions to various Democrats in local races, and raised over $16 million to clear court fines for nearly 32,000 Black and Hispanic Florida voters with felony convictions. Bloomberg contributed $19 million to a pro-Biden super PAC in support of Biden's reelection in 2024.

Philanthropy
In August 2010, Bloomberg signed The Giving Pledge, whereby the wealthy pledge to give away at least half of their wealth. In his lifetime, he has given away $17.4 billion overall including $3 billion in 2023, when he was America's highest giving philanthropist, according to Chronicle of Philanthropy. He has been in the top ten on the publication's list of America's biggest donors since 2004.

His Bloomberg Philanthropies foundation focuses on public health, the arts, government innovation, the environment, and education. Through the foundation, he donated or pledged $767 million in 2018, and more than $1 billion in 2019.

2011 recipients included the Campaign for Tobacco-Free Kids; Centers for Disease Control and Prevention; Johns Hopkins Bloomberg School of Public Health; World Lung Foundation and the World Health Organization. According to The New York Times, Bloomberg was an "anonymous donor" to the Carnegie Corporation from 2001 to 2010, with gifts ranging from $5 million to $20 million each year. The Carnegie Corporation distributed these contributions to hundreds of New York City organizations ranging from the Dance Theatre of Harlem to Gilda's Club, a non-profit organization that provides support to people and families living with cancer. He continues to support the arts through his foundation.

Bloomberg gave $254 million in 2009 to almost 1,400 nonprofit organizations, saying, "I am a big believer in giving it all away and have always said that the best financial planning ends with bouncing the check to the undertaker."

COVID-19 response
During the 2020 COVID-19 pandemic and its aftermath, Bloomberg through his foundation committed to a wide range of urgent causes including researching treatments and vaccines, leading contact tracing to root out the virus, supporting the World Health Organization, and funding global efforts to fight the spread of the disease and protect vulnerable populations. Action included:

 * Cofounding a $75 million fund for nonprofits impacted by COVID-19 in New York City
 * Donating $6 million to World Central Kitchen to serve meals to health care workers in New York City
 * Partnering with Johns Hopkins University to train COVID-19 contact tracers through its school of public health and search for a treatment of the virus.
 * Convening mayors through a partnership with Harvard College to learn and discuss their pandemic response, featuring a bipartisan roster of speakers and attendees.
 * Leading New York's contact tracing effort
 * Launching an information and action sharing network for cities through the National League of Cities
 * Supporting international efforts to combat the spread of COVID-19 and prepare regional leaders through the International Rescue Committee, the World Health Organization, Vital Strategies and other partners

Environmental advocacy
Bloomberg is an environmentalist and has advocated policy to fight climate change at least since he became the mayor of New York City. In September 2023, the New York Times called Bloomberg "perhaps the world's single largest funder of climate activism." At the national level, Bloomberg has consistently pushed for transitioning the United States' energy mix from fossil fuels to clean energy. In July 2011, Bloomberg Philanthropies donated $50 million to Sierra Club's Beyond Coal campaign, allowing the campaign to expand its efforts to shut down coal-fired power plants from 15 states to 45 states. In 2015, Bloomberg announced an additional $30 million contribution to the Beyond Coal initiative, matched with another $30 million by other donors, to help secure the retirement of half of America's fleet of coal plants by 2017. In July 2017, Europe Beyond Coal was established to phase out use of coal on the continent by 2030. Austria closed its final coal-fired plant in April 2020. In early June 2019, Bloomberg pledged $500 million to reduce climate impacts and shut remaining coal-fired power plants by 2030 via the new Beyond Carbon initiative. In September 2023, Bloomberg committed another $500 million to Beyond Carbon to "finish the job on coal."

Bloomberg Philanthropies awarded a $6 million grant to the Environmental Defense Fund in support of strict regulations on fracking in the 14 states with the heaviest natural gas production.

In 2013, Bloomberg and Bloomberg Philanthropies launched the Risky Business initiative with former Treasury Secretary Hank Paulson and hedge-fund billionaire Tom Steyer. The joint effort worked to convince the business community of the need for more sustainable energy and development policies, by quantifying and publicizing the economic risks the United States faces from the impact of climate change. In January 2015, Bloomberg led Bloomberg Philanthropies in a $48-million partnership with the Heising-Simons family to launch the Clean Energy Initiative. The initiative supports state-based solutions aimed at ensuring America has a clean, reliable, and affordable energy system.

Since 2010, Bloomberg has taken an increasingly global role on environmental issues. From 2010 to 2013, he served as the chairman of the C40 Cities Climate Leadership Group, a network of the world's biggest cities working together to reduce carbon emissions. During his tenure, Bloomberg worked with President Bill Clinton to merge C40 with the Clinton Climate Initiative, with the goal of amplifying their efforts in the global fight against climate change worldwide. He serves as the president of the board of C40 Cities. In January 2014, Bloomberg began a five-year commitment totaling $53 million through Bloomberg Philanthropies to the Vibrant Oceans Initiative. The initiative partners Bloomberg Philanthropies with Oceana, Rare, and Encourage Capital to help reform fisheries and increase sustainable populations worldwide. In 2018, Bloomberg joined Ray Dalio in announcing a commitment of $185 million towards protecting the oceans.

In 2014, United Nations Secretary General Ban Ki-moon appointed Bloomberg as his first Special Envoy for Cities and Climate Change to help the United Nations work with cities to prevent climate change. In September 2014, Bloomberg convened with Ban and global leaders at the UN Climate Summit to announce definite action to fight climate change in 2015. In 2018, Ban's successor António Guterres appointed Bloomberg as UN envoy for climate action. He resigned in November 2019, in the run-up to his presidential campaign. On 5 February 2021, however, he was re-appointed by Guterres as his Special Envoy on Climate Ambition and Solutions in the lead-up to the climate conference in Scotland scheduled for November 2021.

In late 2014, Bloomberg, Ban Ki-moon, and global city networks ICLEI-Local Governments for Sustainability (ICLEI), C40 Cities Climate Leadership Group (C40) and United Cities and Local Governments (UCLG), with support from UN-Habitat, launched the Compact of Mayors, a global coalition of mayors and city officials pledging to reduce local greenhouse gas emissions, enhance climate resilience, and track their progress transparently. To date, over 250 cities representing more than 300 million people worldwide and 4.1 percent of the total global population, have committed to the Compact of Mayors, which was merged with the Covenant of Mayors in June 2016.

In 2015, Bloomberg and Paris mayor Anne Hidalgo created the Climate Summit for Local Leaders. which convened assembled hundreds of city leaders from around the world at Paris City Hall to discuss fighting climate change. The Summit concluded with the presentation of the Paris Declaration, a pledge by leaders from assembled global cities to cut carbon emissions by 3.7 gigatons annually by 2030.

During the 2015 UN Climate Change Conference in Paris, Mark Carney, Governor of the Bank of England and chair of the Financial Stability Board, announced that Bloomberg would lead a new global task force designed to help industry and financial markets understand the growing risks of climate change.

Following President Donald Trump's announcement that the U.S. government would withdraw from the Paris climate accord, Bloomberg outlined a coalition of cities, states, universities and businesses that had come together to honor America's commitment under the agreement through 'America's Pledge'. Bloomberg offered up to $15 million to the UNFCCC, the UN body that assists countries with climate change efforts. About a month later, Bloomberg and California Governor Jerry Brown announced that the America's Pledge coalition would work to "quantify the actions taken by U.S. states, cities and business to drive down greenhouse gas emissions consistent with the goals of the Paris Agreement." In announcing the initiative, Bloomberg said "the American government may have pulled out of the Paris agreement, but American society remains committed to it." Two think tanks, World Resource Institute and the Rocky Mountain Institute, will work with America's Pledge to analyze the work cities, states and businesses do to meet the U.S. commitment to the Paris agreement.

In May 2019, Bloomberg announced a 2020 Midwestern Collegiate Climate Summit in Washington University in St. Louis with the aim to bring together leaders from Midwestern universities, local government and the private sector to reduce climate impacts in the region.

Expanding on the work of Beyond Coal and Beyond Carbon, Bloomberg launched Beyond Petrochemicals in September 2022. The campaign takes aim at the rapid expansion of U.S. petrochemicals and plastic pollution. The $85 million campaign aims to block the construction of 120 proposed petrochemical projects in Louisiana, Texas and the Ohio River Valley.

Bloomberg serves as global adviser to the winners of the Earthshot Prize. His foundation Bloomberg Philanthropies is a founding partner of the Prize which awards GB£1,000,000 to each of five winners each year whose work will achieve ambitious climate and sustainability goals by 2030. The 2023 finalists were announced at the Earthshot Prize Innovation Summit in September 2023 in New York, and the five winners were announced in November 2023 in Singapore.

Johns Hopkins University philanthropy
As of 2024, Bloomberg has given more than $4.55 billion to Johns Hopkins University, his alma mater, making him "the most generous living donor to any education institution in the United States." His first contribution, in 1965, had been $5. He made his first $1 million commitment to JHU in 1984, and subsequently became the first individual to exceed $1 billion in lifetime donations to a single U.S. institution of higher education.

Bloomberg's contributions to Johns Hopkins "fueled major improvements in the university's reputation and rankings, its competitiveness for faculty and students, and the appearance of its campus," and included construction of a children's hospital (the Charlotte R. Bloomberg Children's Center Building, named after Bloomberg's mother); a physics building, a school of public health (the Johns Hopkins Bloomberg School of Public Health), libraries, and biomedical research facilities, including the Institute for Cell Engineering, a stem-cell research institute within the School of Medicine, and the Malaria Research Institute within the School of Public Health. In 2013, Bloomberg committed $350 million to Johns Hopkins, five-sevenths of which were allocated to the Bloomberg Distinguished Professorships. In 2016, Bloomberg Philanthropies contributed $300 million to establish the Bloomberg American Health Initiative. Bloomberg also funded the launch of the Bloomberg–Kimmel Institute for Cancer Immunotherapy within the Johns Hopkins School of Medicine in East Baltimore, with a $50 million gift; an additional $50 million was given by philanthropist Sidney Kimmel, and $25 million by other donors. It will support cancer therapy research, technology and infrastructure development, and private sector partnerships. In 2016, Bloomberg joined Vice President Joe Biden for the institute's formal launch, embracing Biden's "Cancer Moonshot" initiative, which seeks to find a cure for cancer through national coordination of government and private sector resources. In 2018, Bloomberg contributed a further gift of $1.8 billion to Johns Hopkins, allowing the university to practice need-blind admission and meet the full financial need of admitted students.

In 2024, Bloomberg announced a $1 billion gift to Johns Hopkins University to make tuition free for all medical school students whose families make under $300,000 a year, beginning in the fall of 2024. The donation also increases financial aid for students enrolled in nursing, public health and other graduate programs.

Other educational and research philanthropy
In 1996, Bloomberg endowed the William Henry Bloomberg Professorship at Harvard University with a $3 million gift in honor of his father, who died in 1963, saying, "throughout his life, he recognized the importance of reaching out to the nonprofit sector to help better the welfare of the entire community."

In 2015, Bloomberg donated $100 million to Cornell Tech, the applied sciences graduate school of Cornell University on the school's Roosevelt Island campus. Through Bloomberg Philanthropies, Bloomberg established the American Talent Initiative in 2016 which is committed to increasing the number of lower-income high-achieving students attending elite colleges. Bloomberg Philanthropies also supports CollegePoint which has provided advising to lower- and moderate-income high school students since 2014. In 2016, the Museum of Science, Boston announced a $50 million gift from Bloomberg. Bloomberg credited the museum with sparking his intellectual curiosity as a patron and student during his youth in Medford, Massachusetts. It is the largest donation in the museum's 186-year history.

Urban innovation philanthropy
In July 2011, Bloomberg launched a $24 million initiative to fund "Innovation Delivery Teams" in five cities. The teams are one of Bloomberg Philanthropies' key goals: advancing government innovation. In December 2011, Bloomberg Philanthropies launched a partnership with online ticket search engine SeatGeek to connect artists with new audiences. Called the Discover New York Arts Project, the project includes organizations HERE, New York Theatre Workshop, and the Kaufman Center.

In 2013, Bloomberg announced the Mayors Challenge competition to drive innovation in American cities. The program was later expanded to competitions in Latin America and Europe.

In 2016, Bloomberg gave Harvard $32 million to create the Bloomberg Harvard City Leadership Initiative within Harvard Kennedy School's Ash Center for Democratic Governance and Innovation; the initiative provides training to mayors and their aides on innovative municipal leadership and challenges facing cities. Since its founding, 275 mayors and more than 400 top city aides have gone through the program, prompting Time Magazine to call Bloomberg 'the nation's mayoral tutor.'

In March 2021, Bloomberg gave Harvard $150 million to create the Bloomberg Center for Cities to support mayors.

Tobacco, gun control and public health

Bloomberg has been a longtime donor to global tobacco control efforts. Bloomberg has donated close to $1 billion to the World Health Organization (WHO) to promote anti-smoking efforts, including $125 million in 2006, $250 million in 2008, and $360 million, making Bloomberg Philanthropies the developing world's biggest funder of tobacco-control initiatives. In 2013, it was reported that Bloomberg had donated $109.24 million in 556 grants and 61 countries to campaigns against tobacco. Bloomberg's contributions are aimed at "getting countries to monitor tobacco use, introduce strong tobacco-control laws, and create mass media campaigns to educate the public about the dangers of tobacco use." Bloomberg Philanthropies and the Campaign for Tobacco-Free Kids jointly launched a $160 million, three-year campaign against youth use of electronic cigarettes (vaping).

In Bloomberg is the co-founder of Everytown for Gun Safety (formerly Mayors Against Illegal Guns), a gun control advocacy group.

In 2016, the World Health Organization appointed Bloomberg as its Global Ambassador for Noncommunicable Diseases.

Other philanthropy
Through Bloomberg Philanthropies, Bloomberg supported the Fresh Air Fund's creation of 'Open Spaces in the City' in summer 2020 to provide socially-distant areas for kids to play during the COVID-19 pandemic, as well as jobs for local teens. He donated $3 million to the construction of a new public library in his hometown of Medford and $75 million for The Shed, a new arts and cultural center in Hudson Yards, Manhattan.

In September 2023, the Perelman Performing Arts Center opened with $130 million of support from Bloomberg, who serves as its chair. The $500 million art center is the final major piece of the redevelopment of the site where the World Trade Center once stood.

Following the Hamas attack on Israel in October 2023, Bloomberg committed to matching donations to the Israeli Red Cross, known as Magen David Adom. By October 19, 2023, Bloomberg had matched $25 million in donations to the ambulance and Medivac service.

Bloomberg also endowed his hometown synagogue, Temple Shalom, which was renamed for his parents as the William and Charlotte Bloomberg Jewish Community Center of Medford.

Bloomberg hosted the Global Business Forum in 2017, during the annual meeting of the United Nations General Assembly; the gathering featured international CEOs, heads of state, and other prominent speakers.

In 2009 Bloomberg met with other billionaires such as Warren Buffett, Bill Gates, Ted Turner and Oprah Winfrey to address issues ranging from the environment, health care and concerns over population growth. Although no formal organization was established, the effort was understood to be designed to help bring various philanthropic projects of the mega-donors into a more unified effort to address various problems on our planet.

Family and relationships
In 1975, Bloomberg married Susan Elizabeth Barbara Brown, a British national from Yorkshire, United Kingdom. They have two daughters: Emma Beth (born c. 1979) and Georgina Leigh (born 1983), who were featured on Born Rich, a 2003 documentary film about the children of the extremely wealthy. Bloomberg divorced Brown in 1993, but he has said she remains his "best friend." Since 2000, Bloomberg has lived with former New York state banking superintendent Diana Taylor. Emma Bloomberg was married to Chris Frissora, son of Mark Frissora, and they had a daughter with a hybrid surname Frissberg.

Bloomberg's younger sister, Marjorie Tiven, has been commissioner of the New York City Commission for the United Nations, Consular Corps and Protocol, since February 2002.

Relation with the Sackler family
During the opioid epidemic in the United States, Mortimer Sackler — son of a co-founder of the company, Purdue Pharma, and a member of its board, met with Bloomberg to "seek his help and guidance on the current issues we are facing". Purdue's head of communications, Josephine Martin, added "Any positive news or ability to get our side out is through Bloomberg. We have given them exclusives and they have treated us very well." Bloomberg also advised Mortimer Sackler to consult Stu Loeser to help manage communications.

Religion
Although he attended Hebrew school, had a bar mitzvah, and his family kept a kosher kitchen, Bloomberg today lives a mostly secular religious life, attending synagogue mainly during the High Holidays and a Passover Seder with his sister, Marjorie Tiven. Neither of his daughters had bat mitzvahs, nor does either daughter follow a religiously Jewish lifestyle, such as abiding kosher dietary restrictions or keeping the Jewish sabbath.

Public image and lifestyle
Throughout his business career, Bloomberg has made numerous statements which have been considered by some to be insulting, derogatory, sexist or misogynistic. When working on Wall Street in the 1960s and 1970s, Bloomberg claimed in his 1997 autobiography, he had "a girlfriend in every city". On various occasions, Bloomberg allegedly commented "I'd do her", regarding certain women, some of whom were coworkers or employees. Bloomberg later said that by "do", he meant that he would have a personal relationship with the woman. Further, the Washington Post acquired a booklet of Bloomberg quotes, which included: “If women wanted to be appreciated for their brains, they’d go to the library instead of to Bloomingdale’s.” Bloomberg's staff told the New York Times that he now regrets having made "disrespectful" remarks concerning women.

During his term as mayor, he lived at his own home on the Upper East Side of Manhattan instead of Gracie Mansion, the official mayoral residence. In 2013, he owned 13 properties in various countries around the world, including a $20 million Georgian mansion in Southampton, New York. In 2015, he acquired 4 Cheyne Walk, a historical property in Cheyne Walk, Chelsea, London, which once belonged to writer George Eliot. Bloomberg and his daughters own houses in Bermuda and stay there frequently.

Bloomberg stated that during his mayoralty, he rode the New York City Subway on a daily basis, particularly in the commute from his 79th Street home to his office at City Hall. An August 2007 story in The New York Times stated that he was often seen chauffeured by two New York Police Department-owned SUVs to an express train station to avoid having to change from the local to the express trains on the IRT Lexington Avenue Line. He supported the construction of the 7 Subway Extension and the Second Avenue Subway; in December 2013, Bloomberg took a ceremonial ride on a train to the new 34th Street station to celebrate a part of his legacy as mayor.

During his tenure as mayor, Bloomberg made cameos playing himself in the films The Adjustment Bureau and New Year's Eve, as well as in episodes of 30 Rock, Curb Your Enthusiasm, The Good Wife, and two episodes of Law & Order.

Bloomberg is a private pilot. He owns six airplanes: three Dassault Falcon 900s, a Beechcraft B300, a Pilatus PC-24, and a Cessna 182 Skylane. Bloomberg also owns two helicopters: an AW109 and an Airbus helicopter and as of 2012 was near the top of the waiting list for an AW609 tiltrotor aircraft. In his youth he was a licensed amateur radio operator, was proficient in Morse code, and built ham radios.

Bloomberg's fortune is managed by Willett Advisors, an investment firm that serves as his family office.

Awards and honors
In 2024, President Joe Biden awarded Bloomberg the Presidential Medal of Freedom, the Nation's highest civilian honor.

Bloomberg has received honorary degrees from Tufts University (2007), Bard College (2007), Rockefeller University (2007), the University of Pennsylvania (2008), Fordham University (2009), Williams College (2014),  Harvard University (2014), the University of Michigan (2016), Villanova University (2017) and Washington University in St. Louis (2019). Bloomberg was the speaker for Princeton University's 2011 baccalaureate service.

On May 27, 2010, Bloomberg delivered the commencement speech at his alma mater, Johns Hopkins University. In addition, he was invited to and delivered guest remarks for the Johns Hopkins Class of 2020. Other notable guest speakers during the virtual ceremony included Reddit co-founder and Commencement speaker Alexis Ohanian; Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases and a leading member of the White House Coronavirus Task Force; and senior class president Pavan Patel

Bloomberg has received the Yale School of Management's Award for Distinguished Leadership in Global Capital Markets (2003); Golden Plate Award of the American Academy of Achievement presented by Ehud Barak (2004); Barnard College's Barnard Medal of Distinction (2008); the Robert Wood Johnson Foundation Leadership for Healthy Communities' Healthy Communities Leadership Award (2009); and the Jefferson Awards Foundation's U.S. Senator John Heinz Award for Greatest Public Service by an Elected or Appointed Official (2010). He was the inaugural laureate of the annual Genesis Prize for Jewish values in 2013, and donated the $1 million prize money to a global competition, the Genesis Generation Challenge, to identify young adults' big ideas to better the world.

Bloomberg was named the 39th most influential person in the world in the 2007 and 2008 Time 100. In 2010, Vanity Fair ranked him #7 in its "Vanity Fair 100" list of influential figures.

In 2014, Queen Elizabeth II appointed Bloomberg an Honorary Knight Commander of the Order of the British Empire for his "prodigious entrepreneurial and philanthropic endeavors, and the many ways in which they have benefited the United Kingdom and the U.K.-U.S. special relationship."

Books and other works
Bloomberg, with Matthew Winkler, wrote an autobiography, Bloomberg by Bloomberg, published in 1997 by Wiley. A second edition was released in 2019, ahead of Bloomberg's presidential run. Bloomberg and former Sierra Club Executive Director Carl Pope co-authored Climate of Hope: How Cities, Businesses, and Citizens Can Save the Planet (2017), published by St. Martin's Press; the book appeared on the New York Times hardcover nonfiction best-seller list. Bloomberg has written a number of op-eds in The New York Times about various issues, including an op-ed supporting state and local efforts to fight climate change (2017), an op-ed about his donation of $1.8 billion in financial aid for college students and support for need-blind admission policies (2018); an op-ed supporting a ban on flavored e-cigarettes (2019); and an op-ed supporting policies to reduce economic inequality (2020).

title: Michael Bloomberg


text:
Three-phase electric power

Three-phase electric power (abbreviated 3ϕ ) is a common type of alternating current (AC) used in electricity generation, transmission, and distribution. It is a type of polyphase system employing three wires (or four including an optional neutral return wire) and is the most common method used by electrical grids worldwide to transfer power.

Three-phase electrical power was developed in the 1880s by several people. In three-phase power, the voltage on each wire is 120 degrees phase shifted relative to each of the other wires. Because it is an AC system, it allows the voltages to be easily stepped up using transformers to high voltage for transmission and back down for distribution, giving high efficiency.

A three-wire three-phase circuit is usually more economical than an equivalent two-wire single-phase circuit at the same line-to-ground voltage because it uses less conductor material to transmit a given amount of electrical power. Three-phase power is mainly used directly to power large induction motors, other electric motors and other heavy loads. Small loads often use only a two-wire single-phase circuit, which may be derived from a three-phase system.

Terminology
The conductors between a voltage source and a load are called lines, and the voltage between any two lines is called line voltage. The voltage measured between any line and neutral is called phase voltage. For example, for a 208/120-volt service, the line voltage is 208 volts, and the phase voltage is 120 volts.

History
Polyphase power systems were independently invented by Galileo Ferraris, Mikhail Dolivo-Dobrovolsky, Jonas Wenström, John Hopkinson, William Stanley Jr., and Nikola Tesla in the late 1880s.

Three phase power evolved out of electric motor development. In 1885, Galileo Ferraris was doing research on rotating magnetic fields. Ferraris experimented with different types of asynchronous electric motors. The research and his studies resulted in the development of an alternator, which may be thought of as an alternating-current motor operating in reverse, so as to convert mechanical (rotating) power into electric power (as alternating current). On 11 March 1888, Ferraris published his research in a paper to the Royal Academy of Sciences in Turin.

Two months later Nikola Tesla gained for a three-phase electric motor design, application filed October 12, 1887. Figure 13 of this patent shows that Tesla envisaged his three-phase motor being powered from the generator via six wires.

These alternators operated by creating systems of alternating currents displaced from one another in phase by definite amounts, and depended on rotating magnetic fields for their operation. The resulting source of polyphase power soon found widespread acceptance. The invention of the polyphase alternator is key in the history of electrification, as is the power transformer. These inventions enabled power to be transmitted by wires economically over considerable distances. Polyphase power enabled the use of water-power (via hydroelectric generating plants in large dams) in remote places, thereby allowing the mechanical energy of the falling water to be converted to electricity, which then could be fed to an electric motor at any location where mechanical work needed to be done. This versatility sparked the growth of power-transmission network grids on continents around the globe.

Mikhail Dolivo-Dobrovolsky developed a three-phase electrical generator and a three-phase electric motor in 1888 and studied star and delta connections. His three-phase three-wire transmission system was displayed in 1891 in Germany at the International Electrotechnical Exhibition, where Dolivo-Dobrovolsky used the system to transmit electric power at the distance of 176 km (110 miles) with 75% efficiency. In 1891 he also created a three-phase transformer and short-circuited (squirrel-cage) induction motor. He designed the world's first three-phase hydroelectric power plant in 1891. Inventor Jonas Wenström received in 1890 a Swedish patent on the same three-phase system. The possibility of transferring electrical power from a waterfall at a distance was explored at the Grängesberg mine. A $45 m$ fall at Hällsjön, Smedjebackens kommun, where a small iron work had been located, was selected. In 1893, a three-phase $9.5 Kilovolt|kv$ system was used to transfer 400 horsepower a distance of 15 km (10 miles), becoming the first commercial application.

Principle

In a symmetric three-phase power supply system, three conductors each carry an alternating current of the same frequency and voltage amplitude relative to a common reference, but with a phase difference of one third of a cycle (i.e., 120 degrees out of phase) between each. The common reference is usually connected to ground and often to a current-carrying conductor called the neutral. Due to the phase difference, the voltage on any conductor reaches its peak at one third of a cycle after one of the other conductors and one third of a cycle before the remaining conductor. This phase delay gives constant power transfer to a balanced linear load. It also makes it possible to produce a rotating magnetic field in an electric motor and generate other phase arrangements using transformers (for instance, a two-phase system using a Scott-T transformer). The amplitude of the voltage difference between two phases is $$\sqrt{3} = 1.732\ldots$$ times the amplitude of the voltage of the individual phases.

The symmetric three-phase systems described here are simply referred to as three-phase systems because, although it is possible to design and implement asymmetric three-phase power systems (i.e., with unequal voltages or phase shifts), they are not used in practice because they lack the most important advantages of symmetric systems.

In a three-phase system feeding a balanced and linear load, the sum of the instantaneous currents of the three conductors is zero. In other words, the current in each conductor is equal in magnitude to the sum of the currents in the other two, but with the opposite sign. The return path for the current in any phase conductor is the other two phase conductors.

Constant power transfer is possible with any number of phases greater than one. However, two-phase systems do not have neutral-current cancellation and thus use conductors less efficiently, and more than three phases complicates infrastructure unnecessarily. Additionally, in some practical generators and motors, two phases can result in a less smooth (pulsating) torque.

Three-phase systems may have a fourth wire, common in low-voltage distribution. This is the neutral wire. The neutral allows three separate single-phase supplies to be provided at a constant voltage and is commonly used for supplying multiple single-phase loads. The connections are arranged so that, as far as possible in each group, equal power is drawn from each phase. Further up the distribution system, the currents are usually well balanced. Transformers may be wired to have a four-wire secondary and a three-wire primary, while allowing unbalanced loads and the associated secondary-side neutral currents.

Phase sequence
Wiring for three phases is typically identified by colors that vary by country and voltage. The phases must be connected in the correct order to achieve the intended direction of rotation of three-phase motors. For example, pumps and fans do not work as intended in reverse. Maintaining the identity of phases is required if two sources could be connected at the same time. A direct connection between two different phases is a short circuit and leads to flow of unbalanced current.

Advantages and disadvantages
As compared to a single-phase AC power supply that uses two current-carrying conductors (phase and neutral), a three-phase supply with no neutral and the same phase-to-ground voltage and current capacity per phase can transmit three times as much power by using just 1.5 times as many wires (i.e., three instead of two). Thus, the ratio of capacity to conductor material is doubled. The ratio of capacity to conductor material increases to 3:1 with an ungrounded three-phase and center-grounded single-phase system (or 2.25:1 if both use grounds with the same gauge as the conductors). That leads to higher efficiency, lower weight, and cleaner waveforms.

Three-phase supplies have properties that make them desirable in electric power distribution systems:
 * The phase currents tend to cancel out one another, summing to zero in the case of a linear balanced load, which allows a reduction of the size of the neutral conductor because it carries little or no current. With a balanced load, all the phase conductors carry the same current and so can have the same size.
 * Power transfer into a linear balanced load is constant, which, in motor/generator applications, helps to reduce vibrations.
 * Three-phase systems can produce a rotating magnetic field with a specified direction and constant magnitude, which simplifies the design of electric motors, as no starting circuit is required.

However, most loads are single-phase. In North America, single-family houses and individual apartments are supplied one phase from the power grid and use a split-phase system to the panelboard from which most branch circuits will carry 120 V. Circuits designed for higher powered devices such as stoves, dryers, or outlets for electric vehicles carry 240 V.

In Europe, three-phase power is normally delivered to the panelboard and further to higher powered devices.

Generation and distribution

At the power station, an electrical generator converts mechanical power into a set of three AC electric currents, one from each coil (or winding) of the generator. The windings are arranged such that the currents are at the same frequency but with the peaks and troughs of their wave forms offset to provide three complementary currents with a phase separation of one-third cycle (120° or $2π/3$ radians). The generator frequency is typically 50 or 60 Hz, depending on the country.

At the power station, transformers change the voltage from generators to a level suitable for transmission in order to minimize losses.

After further voltage conversions in the transmission network, the voltage is finally transformed to the standard utilization before power is supplied to customers.

Most automotive alternators generate three-phase AC and rectify it to DC with a diode bridge.

Transformer connections
A "delta" (Δ) connected transformer winding is connected between phases of a three-phase system. A "wye" (Y) transformer connects each winding from a phase wire to a common neutral point.

A single three-phase transformer can be used, or three single-phase transformers.

In an "open delta" or "V" system, only two transformers are used. A closed delta made of three single-phase transformers can operate as an open delta if one of the transformers has failed or needs to be removed. In open delta, each transformer must carry current for its respective phases as well as current for the third phase, therefore capacity is reduced to 87%. With one of three transformers missing and the remaining two at 87% efficiency, the capacity is 58% ($2/3$ of 87%).

Where a delta-fed system must be grounded for detection of stray current to ground or protection from surge voltages, a grounding transformer (usually a zigzag transformer) may be connected to allow ground fault currents to return from any phase to ground. Another variation is a "corner grounded" delta system, which is a closed delta that is grounded at one of the junctions of transformers.

Three-wire and four-wire circuits

There are two basic three-phase configurations: wye (Y) and delta (Δ). As shown in the diagram, a delta configuration requires only three wires for transmission, but a wye (star) configuration may have a fourth wire. The fourth wire, if present, is provided as a neutral and is normally grounded. The three-wire and four-wire designations do not count the ground wire present above many transmission lines, which is solely for fault protection and does not carry current under normal use.

A four-wire system with symmetrical voltages between phase and neutral is obtained when the neutral is connected to the "common star point" of all supply windings. In such a system, all three phases will have the same magnitude of voltage relative to the neutral. Other non-symmetrical systems have been used.

The four-wire wye system is used when a mixture of single-phase and three-phase loads are to be served, such as mixed lighting and motor loads. An example of application is local distribution in Europe (and elsewhere), where each customer may be only fed from one phase and the neutral (which is common to the three phases). When a group of customers sharing the neutral draw unequal phase currents, the common neutral wire carries the currents resulting from these imbalances. Electrical engineers try to design the three-phase power system for any one location so that the power drawn from each of three phases is the same, as far as possible at that site. Electrical engineers also try to arrange the distribution network so the loads are balanced as much as possible, since the same principles that apply to individual premises also apply to the wide-scale distribution system power. Hence, every effort is made by supply authorities to distribute the power drawn on each of the three phases over a large number of premises so that, on average, as nearly as possible a balanced load is seen at the point of supply. For domestic use, some countries such as the UK may supply one phase and neutral at a high current (up to 100 A) to one property, while others such as Germany may supply 3 phases and neutral to each customer, but at a lower fuse rating, typically 40–63 A per phase, and "rotated" to avoid the effect that more load tends to be put on the first phase.

Based on wye (Y) and delta (Δ) connection. Generally, there are four different types of three-phase transformer winding connections for transmission and distribution purposes:
 * wye (Y) – wye (Y) is used for small current and high voltage,
 * Delta (Δ) – Delta (Δ) is used for large currents and low voltages,
 * Delta (Δ) – wye (Y) is used for step-up transformers, i.e., at generating stations,
 * wye (Y) – Delta (Δ) is used for step-down transformers, i.e., at the end of the transmission.

In North America, a high-leg delta supply is sometimes used where one winding of a delta-connected transformer feeding the load is center-tapped and that center tap is grounded and connected as a neutral as shown in the second diagram. This setup produces three different voltages: If the voltage between the center tap (neutral) and each of the top and bottom taps (phase and anti-phase) is 120 V (100%), the voltage across the phase and anti-phase lines is 240 V (200%), and the neutral to "high leg" voltage is ≈ 208 V (173%).

The reason for providing the delta connected supply is usually to power large motors requiring a rotating field. However, the premises concerned will also require the "normal" North American 120 V supplies, two of which are derived (180 degrees "out of phase") between the "neutral" and either of the center-tapped phase points.

Balanced circuits
In the perfectly balanced case all three lines share equivalent loads. Examining the circuits, we can derive relationships between line voltage and current, and load voltage and current for wye- and delta-connected loads.

In a balanced system each line will produce equal voltage magnitudes at phase angles equally spaced from each other. With V1 as our reference and V3 lagging V2 lagging V1, using angle notation, and VLN the voltage between the line and the neutral we have:

 * $$\begin{align}

V_1 &= V_\text{LN}\angle 0^\circ, \\ V_2 &= V_\text{LN}\angle{-120}^\circ, \\ V_3 &= V_\text{LN}\angle{+120}^\circ. \end{align}$$

These voltages feed into either a wye- or delta-connected load.

Wye (or, star; Y)

The voltage seen by the load will depend on the load connection; for the wye case, connecting each load to a phase (line-to-neutral) voltages gives

 * $$\begin{align}

I_1 &= \frac{V_1}{|Z_\text{total}|}\angle (-\theta), \\ I_2 &= \frac{V_2}{|Z_\text{total}|}\angle (-120^\circ - \theta), \\ I_3 &= \frac{V_3}{|Z_\text{total}|}\angle ( 120^\circ - \theta), \end{align}$$

where Ztotal is the sum of line and load impedances (Ztotal = ZLN + ZY), and θ is the phase of the total impedance (Ztotal).

The phase angle difference between voltage and current of each phase is not necessarily 0 and depends on the type of load impedance, Zy. Inductive and capacitive loads will cause current to either lag or lead the voltage. However, the relative phase angle between each pair of lines (1 to 2, 2 to 3, and 3 to 1) will still be −120°.

By applying Kirchhoff's current law (KCL) to the neutral node, the three phase currents sum to the total current in the neutral line. In the balanced case:
 * $$I_1 + I_2 + I_3 = I_\text{N} = 0.$$

Delta (Δ)

In the delta circuit, loads are connected across the lines, and so loads see line-to-line voltages:
 * $$\begin{align}

V_{12} &= V_1 - V_2 = (V_\text{LN}\angle 0^\circ) - (V_\text{LN}\angle {-120}^\circ) \\ &= \sqrt{3}V_\text{LN}\angle 30^\circ = \sqrt{3}V_{1}\angle (\phi_{V_1} + 30^\circ), \\

V_{23} &= V_2 - V_3 = (V_\text{LN}\angle {-120}^\circ) - (V_\text{LN}\angle 120^\circ) \\ &= \sqrt{3}V_\text{LN}\angle {-90}^\circ = \sqrt{3}V_{2}\angle (\phi_{V_2} + 30^\circ), \\

V_{31} &= V_3 - V_1 = (V_\text{LN}\angle 120^\circ) - (V_\text{LN}\angle 0^\circ) \\ &= \sqrt{3}V_\text{LN}\angle 150^\circ = \sqrt{3}V_{3}\angle (\phi_{V_3} + 30^\circ). \end{align}$$

(Φv1 is the phase shift for the first voltage, commonly taken to be 0°; in this case, Φv2 = −120° and Φv3 = −240° or 120°.)

Further:
 * $$\begin{align}

I_{12} &= \frac{V_{12}}{|Z_\Delta|} \angle ( 30^\circ - \theta), \\ I_{23} &= \frac{V_{23}}{|Z_\Delta|} \angle (-90^\circ - \theta), \\ I_{31} &= \frac{V_{31}}{|Z_\Delta|} \angle ( 150^\circ - \theta), \end{align}$$

where θ is the phase of delta impedance (ZΔ).

Relative angles are preserved, so I31 lags I23 lags I12 by 120°. Calculating line currents by using KCL at each delta node gives

 * $$\begin{align}

I_1 &= I_{12} - I_{31} = I_{12} - I_{12}\angle 120^\circ \\ &= \sqrt{3}I_{12} \angle (\phi_{I_{12}} - 30^\circ) = \sqrt{3}I_{12} \angle (-\theta) \end{align}$$

and similarly for each other line:

 * $$\begin{align}

I_2 &= \sqrt{3}I_{23} \angle (\phi_{I_{23}} - 30^\circ) = \sqrt{3}I_{23} \angle (-120^\circ - \theta), \\ I_3 &= \sqrt{3}I_{31} \angle (\phi_{I_{31}} - 30^\circ) = \sqrt{3}I_{31} \angle (120^\circ - \theta), \end{align}$$

where, again, θ is the phase of delta impedance (ZΔ).

[[File:Delta connection currents.png|thumb|A delta configuration and a corresponding phasor diagram of its currents. Phase voltages are equal to line voltages, and currents are calculated as The overall power transferred is

]] Inspection of a phasor diagram, or conversion from phasor notation to complex notation, illuminates how the difference between two line-to-neutral voltages yields a line-to-line voltage that is greater by a factor of √3. As a delta configuration connects a load across phases of a transformer, it delivers the line-to-line voltage difference, which is √3 times greater than the line-to-neutral voltage delivered to a load in the wye configuration. As the power transferred is V2/Z, the impedance in the delta configuration must be 3 times what it would be in a wye configuration for the same power to be transferred.

Single-phase loads
Except in a high-leg delta system and a corner-grounded delta system, single-phase loads may be connected across any two phases, or a load can be connected from phase to neutral. Distributing single-phase loads among the phases of a three-phase system balances the load and makes most economical use of conductors and transformers.

In a symmetrical three-phase four-wire wye system, the three phase conductors have the same voltage to the system neutral. The voltage between line conductors is √3 times the phase conductor to neutral voltage:
 * $$V_\text{LL} = \sqrt{3} V_\text{LN}.$$

The currents returning from the customers' premises to the supply transformer all share the neutral wire. If the loads are evenly distributed on all three phases, the sum of the returning currents in the neutral wire is approximately zero. Any unbalanced phase loading on the secondary side of the transformer will use the transformer capacity inefficiently.

If the supply neutral is broken, phase-to-neutral voltage is no longer maintained. Phases with higher relative loading will experience reduced voltage, and phases with lower relative loading will experience elevated voltage, up to the phase-to-phase voltage.

A high-leg delta provides phase-to-neutral relationship of $V_{LL} = 2 V_{LN}$, however, LN load is imposed on one phase. A transformer manufacturer's page suggests that LN loading not exceed 5% of transformer capacity.

Since √3 ≈ 1.73, defining $V_{LN}$ as 100% gives $V_{LL}$ $≈ 100% × 1.73 = 173%$. If $V_{LL}$ was set as 100%, then $V_{LN} ≈ 57.7%$.

Unbalanced loads
When the currents on the three live wires of a three-phase system are not equal or are not at an exact 120° phase angle, the power loss is greater than for a perfectly balanced system. The method of symmetrical components is used to analyze unbalanced systems.

Non-linear loads
With linear loads, the neutral only carries the current due to imbalance between the phases. Gas-discharge lamps and devices that utilize rectifier-capacitor front-end such as switch-mode power supplies, computers, office equipment and such produce third-order harmonics that are in-phase on all the supply phases. Consequently, such harmonic currents add in the neutral in a wye system (or in the grounded (zigzag) transformer in a delta system), which can cause the neutral current to exceed the phase current.

Three-phase loads
An important class of three-phase load is the electric motor. A three-phase induction motor has a simple design, inherently high starting torque and high efficiency. Such motors are applied in industry for many applications. A three-phase motor is more compact and less costly than a single-phase motor of the same voltage class and rating, and single-phase AC motors above 10 hp are uncommon. Three-phase motors also vibrate less and hence last longer than single-phase motors of the same power used under the same conditions.

Resistive heating loads such as electric boilers or space heating may be connected to three-phase systems. Electric lighting may also be similarly connected.

Line frequency flicker in light is detrimental to high-speed cameras used in sports event broadcasting for slow-motion replays. It can be reduced by evenly spreading line frequency operated light sources across the three phases so that the illuminated area is lit from all three phases. This technique was applied successfully at the 2008 Beijing Olympics.

Rectifiers may use a three-phase source to produce a six-pulse DC output. The output of such rectifiers is much smoother than rectified single phase and, unlike single-phase, does not drop to zero between pulses. Such rectifiers may be used for battery charging, electrolysis processes such as aluminium production and the electric arc furnace used in steelmaking, and for operation of DC motors. Zigzag transformers may make the equivalent of six-phase full-wave rectification, twelve pulses per cycle, and this method is occasionally employed to reduce the cost of the filtering components, while improving the quality of the resulting DC.

In many European countries electric stoves are usually designed for a three-phase feed with permanent connection. Individual heating units are often connected between phase and neutral to allow for connection to a single-phase circuit if three-phase is not available. Other usual three-phase loads in the domestic field are tankless water heating systems and storage heaters. Homes in Europe have standardized on a nominal 230 V ±10% between any phase and ground. Most groups of houses are fed from a three-phase street transformer so that individual premises with above-average demand can be fed with a second or third phase connection.

Phase converters
Phase converters are used when three-phase equipment needs to be operated on a single-phase power source. They are used when three-phase power is not available or cost is not justifiable. Such converters may also allow the frequency to be varied, allowing speed control. Some railway locomotives use a single-phase source to drive three-phase motors fed through an electronic drive.

A rotary phase converter is a three-phase motor with special starting arrangements and power factor correction that produces balanced three-phase voltages. When properly designed, these rotary converters can allow satisfactory operation of a three-phase motor on a single-phase source. In such a device, the energy storage is performed by the inertia (flywheel effect) of the rotating components. An external flywheel is sometimes found on one or both ends of the shaft.

A three-phase generator can be driven by a single-phase motor. This motor-generator combination can provide a frequency changer function as well as phase conversion, but requires two machines with all their expenses and losses. The motor-generator method can also form an uninterruptible power supply when used in conjunction with a large flywheel and a battery-powered DC motor; such a combination will deliver nearly constant power compared to the temporary frequency drop experienced with a standby generator set gives until the standby generator kicks in.

Capacitors and autotransformers can be used to approximate a three-phase system in a static phase converter, but the voltage and phase angle of the additional phase may only be useful for certain loads.

Variable-frequency drives and digital phase converters use power electronic devices to synthesize a balanced three-phase supply from single-phase input power.

Testing
Verification of the phase sequence in a circuit is of considerable practical importance. Two sources of three-phase power must not be connected in parallel unless they have the same phase sequence, for example, when connecting a generator to an energized distribution network or when connecting two transformers in parallel. Otherwise, the interconnection will behave like a short circuit, and excess current will flow. The direction of rotation of three-phase motors can be reversed by interchanging any two phases; it may be impractical or harmful to test a machine by momentarily energizing the motor to observe its rotation. Phase sequence of two sources can be verified by measuring voltage between pairs of terminals and observing that terminals with very low voltage between them will have the same phase, whereas pairs that show a higher voltage are on different phases.

Where the absolute phase identity is not required, phase rotation test instruments can be used to identify the rotation sequence with one observation. The phase rotation test instrument may contain a miniature three-phase motor, whose direction of rotation can be directly observed through the instrument case. Another pattern uses a pair of lamps and an internal phase-shifting network to display the phase rotation. Another type of instrument can be connected to a de-energized three-phase motor and can detect the small voltages induced by residual magnetism, when the motor shaft is rotated by hand. A lamp or other indicator lights to show the sequence of voltages at the terminals for the given direction of shaft rotation.

Alternatives to three-phase

 * Split-phase electric power: Used when three-phase power is not available and allows double the normal utilization voltage to be supplied for high-power loads.
 * Two-phase electric power: Uses two AC voltages, with a 90-electrical-degree phase shift between them. Two-phase circuits may be wired with two pairs of conductors, or two wires may be combined, requiring only three wires for the circuit. Currents in the common conductor add to 1.4 times ($$\sqrt{2}$$ ) the current in the individual phases, so the common conductor must be larger. Two-phase and three-phase systems can be interconnected by a Scott-T transformer, invented by Charles F. Scott. Very early AC machines, notably the first generators at Niagara Falls, used a two-phase system, and some remnant two-phase distribution systems still exist, but three-phase systems have displaced the two-phase system for modern installations.
 * Monocyclic power: An asymmetrical modified two-phase power system used by General Electric around 1897, championed by Charles Proteus Steinmetz and Elihu Thomson. This system was devised to avoid patent infringement. In this system, a generator was wound with a full-voltage single-phase winding intended for lighting loads and with a small fraction (usually 1/4 of the line voltage) winding that produced a voltage in quadrature with the main windings. The intention was to use this "power wire" additional winding to provide starting torque for induction motors, with the main winding providing power for lighting loads. After the expiration of the Westinghouse patents on symmetrical two-phase and three-phase power distribution systems, the monocyclic system fell out of use; it was difficult to analyze and did not last long enough for satisfactory energy metering to be developed.
 * High-phase-order systems: Have been built and tested for power transmission. Such transmission lines typically would use six or twelve phases. High-phase-order transmission lines allow transfer of slightly less than proportionately higher power through a given volume without the expense of a high-voltage direct current (HVDC) converter at each end of the line. However, they require correspondingly more pieces of equipment.
 * DC: AC was historically used because it could be easily transformed to higher voltages for long distance transmission. However modern electronics can raise the voltage of DC with high efficiency, and DC lacks skin effect which permits transmission wires to be lighter and cheaper and so high-voltage direct current gives lower losses over long distances.

Color codes
Conductors of a three-phase system are usually identified by a color code, to facilitate balanced loading and to assure the correct phase rotation for motors. Colors used may adhere to International Standard IEC 60446 (later IEC 60445), older standards or to no standard at all and may vary even within a single installation. For example, in the U.S. and Canada, different color codes are used for grounded (earthed) and ungrounded systems.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Three-phase electric power


text:
Rupert, King of the Romans

Rupert of the Palatinate (Ruprecht von der Pfalz; 5 May 1352 – 18 May 1410), sometimes known as Robert of the Palatinate, a member of the House of Wittelsbach, was Elector Palatine from 1398 (as Rupert III) and King of Germany from 1400 until his death.

Early life
Rupert was born at Amberg in the Upper Palatinate, the son of Elector Palatine Rupert II and Beatrice of Aragon, daughter of King Peter II of Sicily. Rupert's great-granduncle was the Wittelsbach emperor Louis IV. He was raised at the Dominican Liebenau monastery near Worms, where his widowed grandmother Irmengard of Oettingen lived as a nun.

Reign
From his early years Rupert took part in the government of the Electoral Palatinate to which he succeeded on his father's death in 1398. He and the three ecclesiastical prince-electors (of Mainz, Cologne and Trier) met at Lahneck Castle in Oberlahnstein on 20 August 1400 and declared their king, Wenceslaus, deposed. On the next day the same four electors met at Rhens to ballot for Rupert as next German king, thus the majority of the college including the Elector Palatine's own vote. As the Imperial City of Aachen refused to let him enter through its gates, Rupert was crowned by Archbishop Frederick III in Cologne on 6 January 1401.

Lacking a solid power base in the Empire, his rule remained contested by Wenceslaus' family, the mighty House of Luxembourg, though Wenceslaus himself did not take any action to regain his royal title. In the Western Schism, Rupert backed Pope Boniface IX who, however, was reluctant to acknowledge his rule in view of the Luxembourg claims. After the king had won some recognition in Southern Germany, he started a campaign to Italy, where he hoped to crush the rule of Gian Galeazzo Visconti over the thriving Duchy of Milan and to be crowned Holy Roman Emperor by the Pope. In the autumn of 1401 he crossed the Alps, but was defeated at Brescia and in April 1402 Rupert returned to Germany.

The news of this failure increased the disorder in Germany, but the king met with some success in his efforts to restore peace. The Luxembourg resistance waned after Wenceslaus was arrested at Prague Castle by his brother Sigismund in March 1402 and the next year his lordship was finally recognized by the Pope. Rupert also gained the support of England by the marriage of his son Louis with Blanche of Lancaster, daughter of King Henry IV on 6 July 1402. In his Palatinate hereditary lands, Rupert turned out to be a capable ruler.

It was nevertheless only the indolence of Wenceslaus that prevented his overthrow. After attempts to enlarge the king's allodium caused conflicts with his former ally, the Archbishop of Mainz forging an alliance with Count Eberhard III of Württemberg, the Zähringen margrave Bernard I of Baden and several Swabian cities in 1405, Rupert was compelled to make certain concessions. The quarrel was complicated by the Papal Schism, but the king was just beginning to make some headway when he died at his castle of Landskrone near Oppenheim on 18 May 1410 and was buried at the Church of the Holy Spirit in Heidelberg.

On his deathbed Rupert had decreed the division of his heritage among his four surviving sons. He was succeeded as elector by the eldest surviving son, Louis III. The second surviving son, John, received the County Palatine of Neumarkt, the third surviving son, Stephen, Count Palatine of Simmern-Zweibrücken, and the youngest son, Otto, the County Palatine of Mosbach. In the following imperial election on September 20, Louis III voted for Sigismund of Luxembourg, who however lost to his cousin Margrave Jobst of Moravia.

Family and children
He was married in Amberg on 27 June 1374 to Elisabeth, daughter of Burgrave Frederick V of Nuremberg and Elisabeth of Meissen.

They had the following children:
 * 1) Rupert Pipan (20 February 1375, Amberg – 25 January 1397, Amberg)
 * 2) Margaret (1376 – 27 August 1434, Nancy), married on 6 February 1393 to Duke Charles II of Lorraine
 * 3) Frederick (c. 1377, Amberg – 7 March 1401, Amberg)
 * 4) Louis III, Elector Palatine (23 January 1378 – 30 December 1436, Heidelberg)
 * 5) Agnes (1379 – 1401, Heidelberg), married in Heidelberg shortly before  March 1400 to Duke Adolph I of Cleves
 * 6) Elisabeth (27 October 1381 – 31 December 1408, Innsbruck), married in Innsbruck 24 December 1407 to Duke Frederick IV of Austria
 * 7) Count Palatine John of Neumarkt (1383, Neunburg vorm Wald – 13–14 March 1443)
 * 8) Count Palatine Stephen of Simmern-Zweibrücken (23 June 1385 – 14 February 1459, Simmern)
 * 9) Count Palatine Otto I of Mosbach (24 August 1390, Mosbach – 5 July 1461)

Legacy
Rupert's strenuous efforts earned him the surname Clemens ("the Gentle"). He also commissioned the Ruprecht building in Heidelberg Castle.

title: Rupert, King of the Romans


text:
CRC

CRC may refer to:

Science and technology

 * Carboniferous Rainforest Collapse, an event at the end of the Carboniferous period
 * Class-responsibility-collaboration card, used as a brainstorming tool in the design of object-oriented software
 * Clinical research coordinator, responsible for conducting clinical trials
 * Colorectal cancer, the development of cancer in the colon or rectum
 * CRC Energy Efficiency Scheme, formerly the Carbon Reduction Commitment, a UK wide scheme designed to increase energy efficiency in large energy users
 * CRC Handbook of Chemistry and Physics, a reference manual published by CRC Press
 * Cyclic redundancy check, a type of hash function used to produce a checksum in order to detect errors in data storage or transmission

Organizations

 * California Rehabilitation Center, a state prison in the United States Of America
 * Canadian Red Cross
 * Capital Research Center, an American conservative non-profit organization
 * Central Revolutionary Committee (French: Comité révolutionnaire central), an extinct French political party
 * Civilian Response Corps, deployable American federal civilian employees who provide reconstruction and stabilization assistance
 * Commission for Rural Communities, a United Kingdom public body
 * Committee on the Rights of the Child, which reports on implementation of the UN Convention on the Rights of the Child
 * Convention on the Rights of the Child, of the United Nations
 * Communications Research Centre Canada, an agency of Industry Canada
 * Communist, Republican, and Citizen Group, a French parliamentary group
 * Community Rehabilitation Company, a private-sector suppliers of offender rehabilitation services in England and Wales
 * Constitutional Research Council, a Unionist, pro-Brexit funding organisation in Scotland and Northern Ireland
 * Control and Reporting Centre, part of the Air Force control and reporting system in most NATO countries
 * Civil Rights Congress, a United States civil rights organization from 1946 until 1956

Religion

 * CRC Churches International, a Pentecostal Protestant Christian denomination located primarily in Australasia
 * Central Rabbinical Congress, a Haredi group
 * Chicago Rabbinical Council
 * Christian Reformed Church (disambiguation)
 * Christian Revival Church, a Charismatic, Pentecostal and holistic Evangelical movement group
 * Ligue de la contre-réforme catholique

Education and research

 * Cambridge Regional College, a further education college
 * Center for Research and Communication, a Philippine think-tank that later became the University of Asia and the Pacific
 * Cooperative Research Centre, a type of hybrid academic/industry research body existing in Australia
 * Cosumnes River College, a two-year community college in Sacramento, California
 * Crowley's Ridge College, a Christian college in Paragould, Arkansas
 * Cyclotron Research Center and Cyclotron Resource Center, particle accelerator complex at the University of Louvain, Belgium
 * Georgia Tech Campus Recreation Center, the Rec center at Georgia Tech

Companies

 * California Resources Corporation, a petroleum and natural gas company
 * Chicago Recording Company, a recording studio in Chicago
 * China Record Corporation, a large record company, based in Beijing
 * China Resources (operated CRC Supermarkets)
 * China Resources Cement, a cement company parented by China Resources
 * Columbia Record Club, a mail-order music club offered by Columbia Records
 * Computer Research Corporation, an early minicomputer manufacturer
 * CRC-Evans, a pipeline-construction company owned by Stanley Black & Decker
 * CRC Health Group, provider of addiction treatment and educational programs for adults and youth
 * CRC Industries, a worldwide manufacturer of specialist industrial chemicals
 * CRC Press, publisher, originally the Chemical Rubber Company
 * Customer relation centre, a common company department

Places

 * Costa Rica (FIFA and IOC code)
 * Camp Red Cloud, a US Army Camp in Uijeongbu, South Korea

Sports

 * Canadian Rally Championship, a rally racing tournament
 * Canadian Ringette Championships, a national ringette tournament
 * Canadian Rugby Championship, a rugby union tournament
 * Capablanca Random Chess, a 10x8 chess variant
 * Collegiate Rugby Championship, a rugby sevens tournament

Other uses

 * Canada Research Chair, Canadian university research professorships
 * Costa Rican colón, the ISO 4217 currency of Costa Rica
 * Crc (protein), catabolite repression control protein
 * Criminal record check

title: CRC


text:
Sheepshank

A shank is a type of knot that is used to shorten a rope or take up slack, such as the sheepshank. The sheepshank knot is not stable. It will fall apart under too much load or too little load.

The knot has several features which allow a rope to be shortened:

 * It provides two loops, one at each end of the knot which can be used to pass another rope through
 * The knot remains somewhat secure under tension; the coarser the rope the more secure it is (see Disadvantages, below)
 * The knot falls apart easily when tension is removed

Construction methods
A sheepshank knot may be constructed as follows: ...
 * Pull a section of rope back and lay it alongside the rope, so that the rope forms a Z approximately 20 cm long.
 * Flatten the Z so that there are 3 sections of rope lying alongside each other, with two U-bends where the rope reverses direction.
 * At each U-bend, grasp the U-bend in one hand, thus holding two of the rope sections. With the other hand form a small loop in the remaining section and draw it over the U-bend so that the loop forms a half hitch and stays there if the free end of the rope is pulled taut.
 * Many people draw the small loop over facing the wrong way at least half of the time. Instead, make with the U a half-hitch around the other part, by tucking through, then pull the U straight.

 * Repeat at the other U-bend.

An alternative method for quickly constructing a sheepshank is as follows:

 * Create a simple loop in the rope, so that the (left) leading end is on top of the (right) trailing end of the loop.
 * Repeat this process further down the rope to create 3 total loops that overlap slightly (similar to a venn diagram with three circles).
 * Reach through the outer two loops and grab either side of the middle loop and pull outward while also keeping the rest of the rope slightly taut.
 * Once the middle loop is pulled through the outer loops, pull on the free ends of the rope to secure.

The result is a flattened loop which is held at each end by a half hitch. If the sides of the flattened loop are pulled away from each other, the flattened loop ends pull out of the half hitches and the knot falls apart, but if the free ends are pulled taut then the knot remains secure.

Modern usage
Sheepshank knots are typically used for securing loads to trucks or trailers, and in sailing applications.

Disadvantages
The sheepshank was developed before the use of modern "slippery" synthetic ropes. Constructed from such ropes, under load, it can fail. It is strongly advised that an alternative knot be used.

Man-o'war sheepshank
The man-o'war sheepshank is a sheepshank knot with a Handcuff knot in the middle. This configuration with the half-hitches formed close to the central knot is used in rope rescue and is called a Fireman's chair knot.

Sheepshank with Marlinespike hitches
This version of the sheepshank is tied by using slipknots instead of half-hitches. It is one of the safest sheepshank variations.

Kamikaze knot

The kamikaze knot is a slight variant of the sheepshank. To perform a kamikaze knot, a sheepshank is first constructed. While holding sufficient tension on the sheepshank so it will not slip out, the middle rope is sliced. This allows climbers rappelling down cliff faces to keep most of the rope used for the rappel, by tying the knot at the top, and shaking the rope when they reach the bottom. The shaking disconnects the knot at the top, allowing the longer section of rope to fall, meaning only a small amount of rope is retained by the anchor at the top of the cliff. Thin or slippery rope is unsuitable for such a knot, as it can easily slip, and the knot should not be performed unless desperately needed.

Use
This variant of the sheepshank knot appeared in an episode of the TV show Man vs. Wild. Although certainly not invented by him, Bear Grylls uses by cutting one of the lengths of rope in the knot, while rappelling down an edge during the Ireland episode of Man Vs Wild in order to retrieve his rope at the bottom by severing the middle leg of the sheepshank knot before his descent. He refers to it as a "Kamikaze" knot.

Bell-ringer's knot
A simpler variant of the sheepshank wherein a half-hitch is only tied around only one end produces a bell-ringer's knot (ABoK #1147). It will immediately spill under tension, and is used to keep a long rope from the belfry deck when not in use.

Catshank
The catshank is a variant of the sheepshank, clinched by two overhand knots with the bights passed through the twists (one end of the rope must be available to tie the overhands).

Dogshank
The dogshank, or sheepshank pouch knot, is a variant of the sheepshank where the eyes formed at each end have the ends of the rope passed through them to prevents the knot from spilling. At least one end of the rope must be available to tie or untie this knot. It is mostly useful for the hammock-like space it creates.

The dogshank can be thought of as two opposite bowlines where
 * the two ends provide the respective standing lines each with its pinching turn, and
 * the two elbows of the Z-folded middle part provide the bights that pass through the turns and come back from around the standing lines.

title: Sheepshank