AC Electrics -AC Motors: DGCA Technical General questions

Question 1

Synchronous motors are usually supplied by:

Accepted Answer

Three phase AC

Answer

Single phase AC

Answer

DC to the stator

Answer

DC to the stator and AC to the rotor

Question 2

Reversing two phases to a three phase motor will:

Accepted Answer

Cause the motor to run in reverse

Answer

Blow the phase fuses

Answer

Overheat the stator windings

Answer

Stall the motor

Question 3

A synchronous motor runs at a speed that depends upon the supply:

Accepted Answer

Frequency

Answer

Voltage

Answer

Current

Answer

Reactance

Question 4

If one phase of the supply to a three phase motor fails, then:

Accepted Answer

Will run at about half speed but will not start on its next selection

Answer

The motor will continue to run at the same speed

Answer

Will slow down and stop

Answer

Will stop immediately

Question 5

The basic principle of operation of a 3 phase induction motor is:

Accepted Answer

A rotating field created in the stator

Answer

A rotating field created in the rotor

Answer

A stationary field created in the stator

Answer

A stationary field created in the rotor

5 more questions in this chapter, free with an account