MCQs of Synchronous & Auto Synchronous Motors (Electrical Machine - II - 3150910)

Showing 31 to 40 out of 68 Questions

31.

In synchronous motor out of the following losses, which one will have the highest proportion?

32.

In a synchronous motor if the saturation is neglected, then the short circuit ratio (SCR) will be related to the synchronous reactance (xd) as

33.

The synchronous machine is also called a doubly excited machine because

(a)	It can be over-excited
(b)	It needs twice the normal exciting current
(c)	It has two sets of rotor poles
(d)	Both its rotor and stator are excited

34.

If the field of a synchronous motor is over excited, the power factor will be

35.

A synchronous motor is a useful industrial machine due to its property of

(a)	Improving the power factor
(b)	Speed is constant
(c)	Can always be adjusted to operate at the unity power factor
(d)	All of these

36.

Synchronous capacitor (condenser) is

(a)	An ordinary static capacitor bank
(b)	An over-excited synchronous motor driving mechanical load
(c)	An over-excited synchronous motor without mechanical load
(d)	All of these

37.

In a synchronous motor which loss does not vary with the load?

38.

A synchronous motor is said to be ‘floating‘ when it operates at

(a)	Pulsating load
(b)	High load and variable supply voltage
(c)	Varying load
(d)	No load and without losses

39.

A 3 phase synchronous motor is running clockwise. In case the direction of its field current is reversed then

(a)	Winding of the motor will burn
(b)	Motor will run in the reverse direction
(c)	Motor will continue to run in the same direction
(d)	Motor will stop

40.

The rotor copper losses of the synchronous motor is met by

Showing 31 to 40 out of 68 Questions