MCQs of Scalar control or constant V/f control of induction motor (Electric Drives - 3160919)

Showing 31 to 40 out of 52 Questions

31.

In square wave operation mode of 3 phase VSI, the VSI

(a)	Can control the load voltage
(b)	Cannot control the load voltage
(c)	Cannot control the load voltage except by means of dc link voltage
(d)	Cannot control the load voltage except by means of dc link current

32.

In a 3 phase VSI SPWM to use a single carrier signal and preserve the features of PWM technique, the normalized carrier frequency should be

33.

In a 3 phase VSI out of eight valid states, the number of valid states that produce zero ac line voltages is/are

34.

In a three phase voltage source inverters

(a)	Only amplitude of voltage is controllable
(b)	Only phase is controllable
(c)	Both amplitude and phase is controllable
(d)	Amplitude, phase and frequency of voltages should always be controllable

35.

The carrier which are commonly used in constant - frequency PWM is

36.

Out of the following which harmonic is the major contributor of the torque pulsation?

37.

The presence of harmonics

(a)	increase the copper & core losses
(b)	reduces the motor life
(c)	produces pulsation torque
(d)	all of these

38.

Effect of higher order harmonics to 3-Φ I.M. is high than the lower order harmonic.

(a)	True
(b)	False

39.

Out of the following which harmonic does not produce any rotating field?

40.

Out of the following which harmonic is positive sequence hamonic?

Showing 31 to 40 out of 52 Questions