III. Find English equivalents.

разнообразие, асинхронный электродвигатель, управлять,

вентилируемый, якорь, катушки, обмотка, груз, щетка, токарный станок.

IV. Add necessary letter.

Var-ety, sh-nt, Ind-ction, Arm-ture, req-ire, par-ake, encl-sed, Se-ies.

 

V. Make sentences using the next word combinations.

То drive various machines; a few turns of thick wire; to provide the huge torque required; suitable for driving machine tools; boot shunt and field windings.

 

VI. Put questions to all members of the given sentence.

A synchronous motor can be started up without load.

 

VII. Use the offer in all possible forms of time and a kind, adding circumstances where it is necessary

Considerable scientific and technical progress has been achieved in the development of power plants.

VIII. Translate into English

1. Имеется много видов электрических моторов.

2. Они используются для приведения в движение различных машин.

3. Моторы постоянного тока бывают 3-х типов.

4. Обмотка состоит из нескольких витков толстой проволоки.

5. Типы моторов постоянного тока различаются по способу подсоединения катушек к якорю.

IX. Answer the questions.

1. What is the variety of D.C.?

2. Kinds of direct – current?

3. What is called the shunt motor?

4. What has a compound motor?

 

 

ПРАКТИЧЕСКАЯ РАБОТА № 21

A. C. ELECTRIC MOTORS.

Цель: Введение и активизация лексики по теме «Электрические моторы цепи переменного тока».

Оборудование: комплект тестов, раздаточный материал, иллюстрации по теме.

 

Vocabulary

I. Learn these words.

Alternating-current circuit

Single-phase

Polyphase

To be divided

Main

Stator

To set up

A rotating magnetic field

Rotor

 

цепь переменного тока

однофазный

многофазный

делиться на

главный

статор

создавать

переменное магнитное поле

ротор

Cooper bar                                                медные штанги

A slot                                                          прорез, паз

A circumference                                       окружность

A ring                                                         кольцо

To induce                                                   индуктировать, побуждать

A construction                                          конструкция

An inverted alternator                             перевернутый альтернатор

To run                                                           работать

To supply                                                  снабжать, поставлять

A network                                                  система

II. Read the text. Translate and retell in Russian.

A.C.Electric Motors.

Motors for alternating-current circuits may be either single phase or polyphase (two-orthree-phase). They may again be divided into two kinds, named respectively: I. Synchronous; II. Non-or asynchronous, ordinarily called induction motors.

The most widely used a.c.motor is the induction motor. It has two main parts: a) the stationary winding or stator, which sets up a rotating magnetic field, and b) the rotating part of the motor, i.e. the rotor. The rotor of a commercial a.c.motor consists of an iron core with large copper bars placed in slots around the circumferences and connected at both ends to co pper rings. This is called a squirrel-cage rotor. When a rotor is placed in a rotating magnetic field, a large current is induced in it.

A.c. motors are exactly similar in construction to a.c. generators and may be called inverted alternators, since the same machine may be used as either a generator or a motor.

Synchronous motor are very suitable for large powers, where the machine can be started up without load, and once started run for long periods.

For supplying direct-current power networks, the supply comes first from an alternating-current source and is converted to direct current by synchronous convectors or motor generator sets.

 

   III. Add necessary letter.

Pol-phase, sta-or, mag-etic, fi-ld, circum-erence, supp-y, ind-ce, net-ork.

 

IV. Finish the sentences.

1. Motors for alternating-current circuits may be…………..

2. The most widely used a.c. Motor is…………

3. The rotor of a commercial a.c.motor consists…………..

4. A.c. motors are…………

5. Synchronous motor are very……………..

 

V Learn the scheme of A.C. Electric Motors

A.C. Electric Motors

 

             Single-phase                                           Polyphase

Synchronous                                   Asynchronous or Induction

Induction Motors Main Parts