A. Windage loss
B. Copper losses
C. Any of the above
D. None of the above
Related Mcqs:
- A synchronous motor installed at the receiving end substation operates with such an excitation that it takes power at lagging power factor. Now if the applied voltage of the synchronous motor goes down, the power factor of the synchronous motor will___________?
A. remain same
B. go down
C. improve
D. none of the above - A synchronous motor is running on a load with normal excitation. Now if the load on the motor is increased
A. power factor as well as armature current will decrease
B. power factor as well as armature current will increase
C. power factor will increase but armature current will decrease
D. power factor will decrease and armature current will increase - As the load is applied to a synchronous motor, the motor takes more armature current because
A. the increased load has to take more current
B. the rotor by shifting its phase backward causes motor to take more current
C. the back e.m.f. decreases causing an increase in motor current
D. the rotor strengthens the rotating field casuing more motor current - In a 3-phase, 4-pole, 50 Hz synchronous motor, the frequency, pole number and load torque all are halved. The motor speed will be____________?
A. 3000 r.p.m.
B. 1500 r.p.m.
C. 750 r.p.m.
D. none of the above - Which of the following losses is not dissipated by the stator core surface in a synchronous motor?
A. Eddy current losses in the conductors
B. Iron losses in the stator
C. Copper losses in the slot portion of the conductors
D. Windage losses
E. None of the above - The rotor copper losses, in a synchronous motor, are met by____________?
A. d.c. source
B. armature input
C. motor input
D. supply lines - A synchronous motor which works on a leading power factor and does not drive a mechanical load is called as_________?
A. static condenser
B. condenser
C. synchronous condenser
D. none of the above - A synchronous motor can be used as a synchronous capacitor when it is____________?
A. under-loaded
B. over-loaded
C. under-excited
D. over-excited - A synchronous motor can develop synchronous torque:
A. when under loaded
B. while over-excited
C. only at synchronous speed
D. below or above synchronous speed - The maximum constant load torque under which a synchronous motor will pull into synchronism at rated rotor supply voltage and frequency is known as___________?
A. pull-up torque
B. pull-in torque
C. pull-out torque
D. none of the above
