Faults of Motors and Ways of Their Repair

Energy Resources of Today

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1. a) Cover the right column and read the English words. Translate them into Russian and check your translation.

b) Cover the left column and translate the Russian words back into English.

2. Read the words and put down their Russian equivalents:

['komju:teit3] commutator ________________________

t'steitaj

['routaj ['kontaekt] [kan'taekt] ['prouses]

3. Put down the verbs corresponding to the given nouns and translate them:

проверять

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repair slow (adj)

4. Put down the Russian equivalents of these word combinations. Trans­
late them back into English (orally).

air gap __________________________________________________

brush sparks zzziizzzzzzzzzzzzzizzzi^zmm

slow speed___________________________________

excessive speed_________________________________

safety devices __________________________________

5. Answer these questions:

1. What do motors' faults result from?

2. Are there any faults that can be ignored?

3. What makes motors' service life shorter?

4. What does voltage supply stop result in?

5. What processes show the (dis)advantages of devices?

6. Are the words: spark, short, slow, brush, fault, load, test nouns? Are
they verbs? Translate the sentences into Russian:

1. New motors are given a no-load and under a load tests.

2. When the motor is tested it should produce no abnormal noise.

3. In case this noise appears the motor must be disconnected.

4. This generator must be checked; one should give it a test.

5. The motor's brushes seem to be sparking. Can you see the sparks?

6. The windings of the coil are shorted. I have detected a short in the windings.

7. The armature rotates slowly; let's check it up!

8. The speed of rotation is too excessive; it must be slowed down.

9. In case the rotor brushes against the stator, the motor operates slowly. The faulty brushes should be replaced.

Motors may have different faults. A faulty motor does not start, or, when it is started, it operates at an excessive speed.

Its brushes may spark and its windings and the commutator may be overheated and burnt. Besides, a motor may produce an abnormal noise, etc. All these and other faults should be detected and repaired.

In case the motor does not start it may have different faults (see the ta­ble):

Table

7. Complete the sentences using the correct variant:

1. A motor with a fault a) operates normally.

b) operates poorly.

2. Motor brushes spark in case a) they are in normal conditions.

b) they are in poor conditions.

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a) replaced.

b) repaired.

a) pressure is low.

b) pressure is excessive.

a) the rotor brushes against the stator.

b) the stator brushes against the rotor.

8. Answer these questions:

1. When does a motor operate poorly?

2. What should be done in case the motor is overloaded?

3. What should be done in case the fuses are faulty?

4. What should be done in case the rheostat is shorted?

5. What should be done in case the brushes spark?

6. What should be done in case the pressure is low?

7. What should be done in case the ventilation does not operate?

8. What should be done in case the rotor brushes against stator?

9. Say a few words about your electrical engineering laboratory. Are there any faulty devices in it? Have a talk with your groupmate about the faults and the ways to repair them.

10. You know that all electrical devices and installations are constructed of a certain number of components. To these components belong elec­tric power sources, wires, cables, buses, switches, fuses, resistors, rheo- j stats, capacitors, transformers, motors and others.

Let us have a talk about these components. Speak with your group-] mates about their types, their use, operation, possible faults and ways of their repair. Use the table below:

Circuit components

Electric energy source

D.c. generator

D.c. motor

Chemical power source (primary or storage cell)