Efficient Low-Cost Homopolar EV Traction Motors

Homopolar motors are an attractive alternative to conventional dc and induction machines for hybrid and all-electric vehicles, both civilian and military. Known for their high current capability, this inherent characteristic allows high power levels to be achieved from a low voltage power supply for improved safety and reliability over higher voltage systems. Low voltage controllers lend themselves to the use of high efficiency MOSFET switching devices and the unique design simplicity of homopolars provides great potential for reducing the cost of EV drive trains. Work on this project began in May 1995. Full power efficiency is currently at 87% with the majority of losses (about 10%) coming from the brushes. Brush testing is in progress to address efficiency improvements, document wear rates, and confirm operation of several new low-cost and compact actuator designs. Test data obtained so far shows excellent operation of a constant force spring-actuated brush and brush holder design. Brush wear rates at normal driving conditions appear to be far less than those obtained from worst case speed and current loading conditions cited in previous studies. This is very encouraging considering the typical duty cycle of the bus.

To regulate power flow to the motor, UT-CEM is developing a high-current pulse width modulator (PWM) controller based on a highly parallel array of MOSFET switching devices. The final tasks for this program requires setting up a manufacturing line to produce homopolar traction motors, controllers, and gearboxes. Private funds support this portion of the program.

homopolar motor – однополюсныйдвигатель          dc (direct current) – постоянныйток

actuator - силовой привод                                        pulsewidth - длительность импульса

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THE DAY OF INDEPENDENCE

The 4th of July is the American nation's birthday. On this day in 1776 the Continental Congress adopted the Declaration of Independence. On that memorable day the Liberty Bell called the people of Philadelphia (then the capital) to the State House to hear the Declaration of Independence read out. Each city now sponsors its own ceremony - a parade, speeches by public officials. Families and organizations hold daylong picnics. There are baseball games, three legged races, water-melon eating contests, folk dancing and lots of lovely music.

The celebration begins with a day-time Baby Parade. Small children dressed in patriotic costumes ride on diminutive floats draped in red-white-and-blue bunting. The park is filled with flickering lights as the boys who light the candles carry some above their heads and float others in the water. Cattlemen from ranches add to the holiday scene as they ride in to a town on fine horses with glittering silver, trappings. Then a great event comes - a real pie-eating contest. After lunch the crowd moves to the baseball field to cheer the amateur team.

All American people are proud of this holiday and like to celebrate it.

1.    When is the Day of Independence celebrated?

2.    What do people do in this day?

3.    What are traditional games and contests in this day?

3. Topic: “In the Service Center”

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Electromechanical Active Vehicle Suspensions

The UT-CEM EM suspension is a different approach to active suspension systems, referred to as a Near Constant Force Suspension, that allows simplified control strategies and enables smooth rides over rough terrain without the requirement to look-ahead. The concepts were developed in phase one of the program, with TACOM funding, in the context of an active suspension system that utilizes an electromagnetic actuator to replace or supplement torsion spring and rotary damper suspension components for a heavy off-the-road vehicle (an M1 tank). A single road wheel developmental apparatus has been developed and is being tested.

In phase two, the concept was adapted from a trailing arm suspension system, as is found in the M1 MBT, to a dual A-arm suspension, as is found in a HMMWV. Control strategies were expanded from the single wheel station approach developed under the current TACOM project, to a four wheel vehicle. To reduce cost and to reduce the project duration, the four wheel "vehicle," designed to simulate the important characteristics of a HMMWV. This allowed (1) development and refinement of control algorithms on an adaptable test platform, (2) maximum use of "off-the-shelf" components at a stage in the program when it is difficult to totally specify required component performance, and (3) development of necessary specifications and information needed to design a system optimized for a HMMWV.

Phase three of the EM Suspension program has developed customized actuators and control systems to allow installation of a complete system on a HMMWV and a transit bus.

suspension – временная остановка                         roughterrain - местность пересеченная

torsion – кручение, скручивание                 refinement – усовершенствование (процесса)

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NEW YORK

New York is the largest city in the world and the biggest seal port. It is the economic capital of the USA with a population over 11 million.

New York City is situated in the north-east of the USA in the State of New York or the Empire State. It was founded in 1613 by Dutch settlers. Here is the heart of America's business and culture. It is the city of skyscrapers, of Broadway, of Wall Street, which is the centre of American money business.

One of the most interesting sights is New York is the Statue of Liberty, officially named Liberty Enlightening the world. It was sent to the USA by France on July 4, 1886. The Statue of Liberty commemorates the alliance between two countries during the American Revolution. It stands on Liberty is-and in New York Harbor. It is a huge copper-clad statue, one of the largest ever made, of I a woman wearing a crown and holding a torch in her upraised hand. The left arm holds a tablet bearing the date of the Declaration of Independence. During the great period of European immigration to America, the Statue became a powerful symbol of people's hopes for freedom. The Statue of liberty was completely renovated in the middle of 1980s, and a huge flotilia of ships and millions of people celebrated its centennial in 1986.

1.    Where is New York situated?

2.    Who did found New York?

3.    What does the Statue of Liberty symbolize?

3. Topic: “Karl Benz”

Зав. кафедрой_____________ Г.И.МелковЭкзаменатор____________Е.Н.Хайдарова

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