A. windage losses
B. copper losses
C. transformation ratio
D. power scale of circle diagram
Short-circuit test on an induction motor cannot be used to determine___________? Read More »
Polyphase Induction Motors A. twice the full load torque
B. 1.5 times the full load torque
C. equal to full load torque
The starting torque of a 3-phase squirrel cage induction motor is____________? Read More »
Polyphase Induction Motors A. double cage rotor
B. wound rotor
C. short-circuited rotor
D. any of the above
A 3-phase slip ring motor has____________? Read More »
Polyphase Induction Motors A. 730 r.p.m.
B. 960 r.p.m.
C. 1440 r.p.m.
D. 2880 r.p.m.
A. stall after sometime
B. stall immediately
C. continue to run at lower speed without damage
D. get heated and subsequently get damaged
A. Ball bearings
B. Cast iron bearings
C. Bush bearings
D. None of the above
Which type of bearing is provided in small induction motors to support the rotor shaft ? Read More »
Polyphase Induction Motors A. D.C. series motor
B. D.C. shunt motor
C. universal motor
D. none of the above
A. it will run in reverse direction
B. it will pick up very high speed and may go out of step
C. motor takes five to seven times its full load current
D. starting torque is very high
A. in the opposite direction as the direction of the rotating field
B. in the same direction as the direction of the field
C. in any direction depending upon phase squence of supply
A. its power factor goes on decreasing
B. its power factor remains constant
C. its power factor goes on increasing even after full load
D. its power factor goes on increasing up to full load and then it falls again
As load on an induction motor goes on increasing______________? Read More »
Polyphase Induction Motors