Quiz sheet for Three phase induction motor characteristics

A locked rotor test is used to determine

A) starting torque and starting current

B) starting torque and full load current

C) full load torque and starting current

D) full load torque and full load current

ANSWER: A

A motor that has external connections to the armature could be a;

A) Slip ring motor.

B) Squirrel cage induction motor.

C) Capacitor start motor.

D) Capacitor start/run motor.

ANSWER: A

A wound rotor motor is identified by 

A) Slip rings 

B) The rotor cage 

C) The way the stator is wound 

D) The terminal block

ANSWER: A

At near full load speed, torque is directly proportional to 

A) slip

B) voltage

C) current

D) power factor

ANSWER: A

Maximum torque is developed in a squirrel cage induction motor when 

A) rotor reactance is equal to rotor resistance

B) the rotor is at standstill 

C) the rotor is at full speed

D) the rotor is at synchronous speed

ANSWER: A

Of the options below, which starter will give the HIGHEST STARTING TORQUE when line current is limited to 80%

A) Secondary resistance starter

B) Star-delta starter

C) Primary resistance starter 

D) Auto transformer starter

ANSWER: A

The induction motor that can have resistance added to the rotor is 

A) a wound rotor motor

B) high resistance cage

C) low resistance cage

D) dual cage

ANSWER: A

The method of braking that involves reversing two phase called 

A) Plug braking 

B) Dynamic braking 

C) Regenerative braking 

D) Rapid braking 

ANSWER: A

The power factor of an induction motor 

A) increases as load increases

B) decreases as load increases

C) is constant

D) decreases when load increases

ANSWER: A

When compared to conventional single cage machines, dual cage machines 

A) have higher starting torque and slightly lower full load speed.

B) higher starting torque and higher full load speed.

C) lower starting torque and slightly lower full load speed.

D) lower starting torque and higher full load speed.

ANSWER: A


Last modified: Friday, 28 May 2021, 6:09 PM