ELECTROMAGNETIC INDUCTION QUIZ

The rotor of synchronous motor is excited with direct current when the motor _____

Is at standstill

Approches synchronous speed

None of the listed here

Approches half synchronous speed

TRUE ANSWER : ?
YOUR ANSWER : ?

Synchronous capacitor is

None of the listed here

An over excited synchronous motor driving mechanical load

An ordinary static capacitor bank

An over excited synchronous motor running without mechanical load

TRUE ANSWER : ?
YOUR ANSWER : ?

When the synchronous motor runs at synchronous speed, the voltage induced in the damper winding is _____

Zero

None of the listed here

Maximum

minimum

TRUE ANSWER : ?
YOUR ANSWER : ?

The armature current of a synchronous motor will be minimum for ______ power factor.

0.8 leading

0.8 lagging

Unity

None of the listed here

TRUE ANSWER : ?
YOUR ANSWER : ?

In a synchronous motor, the rotor copper loss are met by ______

Armature input

Supply lines

Motor input

Dc source

TRUE ANSWER : ?
YOUR ANSWER : ?

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

lagging

unity

leading

zero

TRUE ANSWER : ?
YOUR ANSWER : ?

The speed of a synchronous motor can be changed by varying _______

Field excitation

Supply frequency

None of the listed here

Mechanical load

TRUE ANSWER : ?
YOUR ANSWER : ?

Hunting in a synchronous motor cannot be due to

variable supply voltage

windage friction

variable load

variable frequency

TRUE ANSWER : ?
YOUR ANSWER : ?

A synchronous motor can operate at

Lagging, leading and unity power factors

Leading power factor

Lagging power factor only

Unity power factor only

TRUE ANSWER : ?
YOUR ANSWER : ?

Leading power factor synchronous motors cost ______ the unity pf motors.

About the same as

Less than

None of the listed here

More than

TRUE ANSWER : ?
YOUR ANSWER : ?

↑