Induction Motor Quiz

What is the formula to calculate the slip speed(Nslip) of three phase induction motor?

• Nslip = Ns-Nr

• Nslip = Nr-Ns

• Nslip = Ns-Nr \ Nr

• Nslip= Ns-Nr \ Ns

The materials use for motor stampings

• Silicon steel

• Carbon steel

• High Carbon steel

• Cast iron

What is the formula to find synchronous Speed, of Ac three phase induction motor?

• synchronous Speed (Ns) = 120 x f /P

• synchronous Speed (Ns) = 120 * P /F

• Synchronous speed (Ns) = 120 /PF

• synchronous Speed (Ns) = PE/120

What is the fuse rate to run a10 H.P three phase induction motor at full load?

• 10A

• 15 A

• 25 A

• 30A

What is the rotor frequency of a there phase squirrel cage induction motor at the time of starting?

• Equal to supply frequency

• 3 times less then supply frequency

• 3 times more than supply frequency

• Root 3 times less then supply frequency

How the voltage is received in the rotor of induction motor?

• Direct connection from stator

• Due to back e.m.f produced in stator

• Direct connection to rotor from supply.

• By the transformer action of stator.

Which method is applied to control the speed of three phase squirrel cage induction motor from its rotor side?

• changing applied voltage

• changing applied frequency

• changing the number of poles

• Cascade operation

Which loss of three phase induction motor is determine by blocked rotor test?

• Hysteresis loss

• Eddy Current loss

• Friction loss

• Copper loss

Which type of test is conducted using internal growler in AC motor winding?

• Ground test

• short circuit test

• Continuity test

• Polarity test

What is the purpose of using thermal cut out in addition to fuse in A.C motor circuit?

• Protect from heavy load

• Protect against high voltage

• Allow for continuous over loading

• Protect against dead short circuit