Search
.Management Sciences
Category: Synchronous Motors
In which of the following motors the stator and rotor magnetic field rotate at the same speed?
A. Universal motor
B. Synchronous motor
C. Induction motor
D. Reluctance motor
An over excited synchronous motor is used for____________?
A. fluctuating loads
B. variable speed loads
C. low torque loads
D. power factor corrections
A three-phase synchronous motor will have_____________?
A. no slip-rings
B. one slip-ring
C. two slip-rings
D. three slip-rings
The armature current of the synchronous motor
A. has large values for low excitation i niy
B. has large values for high excitation only
C. has large values for low and high excitation
D. any of the above
When the rotor speed, in a synchronous machine, becomes more than the synchronous speed during hunting, the damper bars develop_________________?
A. inductor motor torque
B. induction generator torque
C. synchronous motor torque
D. d.c. motor toque
E. none of the above
The magnitude of field flux in a 3-phase synchronous motor?
A. varies with power factor
B. varies with speed
C. varies with the load
D. remains constant at all loads
A synchronous motor will always stop when:______________?
A. supply voltage fluctuates
B. load in motor varies
C. excitation winding gets disconnected
D. supply voltage frequency changes
The shaft of synchronous motor is made of____________?
A. mild steel
B. chrome steel
C. alnico
D. stainless steel
A synchronous motor connected to infinite bus-bars has at constant full load, 100% excitation and unity power factor. On changing the excitation only, the armature current will have_____________?
A. no change of power factor
B. lagging power factor with over-excitation
C. leading power factor with under-excitation
D. leading power factor with over-excitation
When V is the applied voltage, then the breakdown torque of a synchronous motor varies as_________?
A. V
B. V312
C. V2
D. 1/V
Recent Comments