193 : Which formula is used to find percentage slip in 3q induction?
A :
B :
C :
D :
194 : Which speed of 3-phase induction motor runs?
A : Above synchronous speed
B : Below synchronous speed
C : Equal to synchronous speed
D : At slip speed
195 : What is the value of slip at the time of starting of 3 phase induction motor?
A : Two
B : Three
C : One
D : Zero
196 : Which is directly proportional to torque in 3 phase induction motor?
A : Rotor power factor
B : Stator frequency
C : Number of poles
D : Supply voltage
197 : What is phase angle difference between three windings in three phase squirrel cage induction motor?
A : 360°
B : 90°
C : 120°
D : 30°
198 : Which material is used to wound outer cage rotor bars of a double squirrelcage induction motor?
A : Brass
B : Aluminium
C : Copper
D : Silicon steel
199 : Which type of rotor is used in squirrelcage induction motor?
A : Wound type
B : Squirrel cage
C : Slipring type
D : Projecting type
200 : Why rotor bars of squirrel cage induction motor is skewed?
A : Reduce magnetic humming
B : Reduce losses
C : Improve efficiency
D : Improve capacity
201 : How to change the direction of rotation of a 3f squirrel cage induction motor?
A : By interchanging three terminals
B : By interchanging any two terminals
C : By disconnecting one terminal
D : By reducing the applied voltage
202 : Which type of starter is recommended to start upto 3 HP squirrelcage induction motors?
A : DOL starter
B : Auto transfer starter
C : Star-delta starter
D : Rotor resistance starter
203 : Which starter is in simple expensive and easy to start?
A : Rotor resistance starter
B : DOL starter
C : Semi automatic star delta starter
D : Auto transformer starter
204 : Which device in DOL starter provides effective protection against over load?
A : Holding coil
B : Back up fuse
C : Thermal relay
D : Push button switch
205 : How many number of contactors are used in a semi automatic star delta starter?
A : 6
B : 4
C : 5
D : 3
206 : Which type of AC 3 phase motor starter this BIS symbol represents?
A : Star delta starter
B : Rheostatic starter
C : Direct online starter
D : Pole changing starter
207 : Name the part marked as X in manual star delta starter?
A : Plunger
B : Lever plate
C : Stop button
D : Over load relay setting
208 : Which is the additional device used in automatic star delta starter than semi automatic star delta starter?
A : Push button station
B : Timer
C : OLR
D : Number of contacts
209 : How many times of starting current in 3f induction motor is reduced, while starting by star delta starter?
A : 3 times
B : 1/3 times
C :
D : 1/2 times
210 : Which device is used in control of a star delta starter to stop the motor?
A : OLR
B : Star contactor
C : Delta contactor
D : Normally closed push button
211 : What is the name of the starter symbol?
A : D.O.L starter
B : Auto transformer starter
C : Automatic star/delta starter
D : Semi automatic star/delta starter
212 : What is the name of the A.C motor starter?
A : DOL starter
B : Auto transformer starter
C : Semi automatic star delta starter
D : Fully automatic star delta starter
213 : Which type of starter is used with reduced voltage tappings for 3 phase induction motor?
A : D.O.L starter
B : Star delta starter
C : Auto transformer starter
D : Rotor resistance starter
214 : How the voltage is reduced in auto transformer starter at the time of starting?
A : By reducing supply voltage
B : By adjusting the tappings by handle
C : By using step down transformer
D : By adding resistance with rotor
215 : Which induction motor, the external resistance is added to rotor circuit?
A : Squirrel cage induction motor
B : Double squirrel cage induction motor
C : Slip ring induction motor
D : Single phase induction motor
216 : Which motor is used to produce high starting torque at variable speed?
A : Repulsion motor
B : Permanent capacitor motor
C : 3 Phase slip ring induction motor
D : 3 Phase single squirrel cage induction motor
217 : Why slip ring induction motor is fitted with wound rotor?
A : To reduce the slip
B : To control the speed
C : To reduce the losses
D : To get high starting and running torque
218 : Which type of starter is used to start and run the 3 phase slip ring induction motor?
A : Direct on-line starter
B : Rotor rheostat starter
C : Auto transformer starter
D : Manual star-delta starter
219 : What is the purpose of using rotor resistance starter to start 3 phase slip ring induction motor?
A : Reduce rotor voltage
B : Increase rotor current
C : Increase the starting torque
D : Reduce the power loss
220 : Why external resistance is included in the rotor circuit at starting through 3 phase slipring induction motor starter?
A : To get high running torque
B : To reduce high starting current
C : To reduce the load current
D : To get increased speed at starting
221 : What is the effect of motor, if the rotor windings in slipring induction motor is open circuited at starting?
A : Will not run
B : Runs at slow speed
C : Runs at very high speed
D : Runs but not able to pull load
222 : Which method is used to control the speed of 3 phase induction motor from stator side?
A : By cascade operation
B : By rotor rheostat control
C : By injecting emf in rotor circuit
D : By changing the applied frequency
223 : Which speed control method of 3 f motor is used only induction motor supplied by generator?
A : Casecade operation method
B : By changing the number of stator poles
C : By injection Emf in rotor circuit
D : By changing the supplied voltage
224 : Which method of speed control is only applicable for 3 phase slipring induction motor?
A : Casecade operation method
B : Rotor rheostat speed control
C : Changing the applied frequency method
D : Changing the number of stator poles method
225 : Which method of speed control of 3 phase induction motor above and below normal speed can be obtained?
A : By rotor rheostat control
B : By changing applied voltage
C : By injecting EMF in rotor circuit
D : By changing the number of stator poles
226 : Which method of speed control of 3 phase induction motor only two speeds can be obtained?
A : By cascade operation
B : By changing the applied voltage
C : By changing the supply frequency
D : By changing the number of stator poles
227 : Which method of speed control can be obtained from rotor side of 3 phase induction motor?
A : Voltage control
B : Cascade operation
C : Pole changing control
D : Supply frequency control
228 : Which principle the current sensing single phasing preventor works?
A : Equal currents with balanced loads
B : Different currents with balanced loads
C : Equal currents with unbalanced loads
D : Different currents with unbalanced loads
229 : What is called, if the order of 3 phase supply voltages reach the maximum value?
A : Phase relation
B : Phase sequence
C : Single phasing
D : Phase distortion
230 : What is the purpose of single phasing preventor?
A : Protects the motor by stopping automatically under balanced load
B : Provides three phase supply in sequence order
C : Prevents the motor from short circuit fault
D : Prevent the motor from over load
231 : Which type of single phase preventer is used for the motor with constant load?
A : Mechanical single phasing preventor with bimetal relay
B : Mechanical single phasing preventer with coils
C : Voltage sewing single phasing preventer
D : Current sewing single phasing preventer
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