In a synchronous motor the armature current has large values for
both high and low excitation
none of the above
low excitation only
high excitation only
both high and low excitation
When the stator windings are connected in such a fashion that the number of poles are made half the speed of the rotor of a synchronous motor
increases to two times the original value
decreases to half the original value
remains same as the original value
tends to becomes zero
increases to two times the original value
Synchronsizingpower of a synchronous machine is
none of the above
inversely proportional to the synchronous reactance
direcly proportional to the synchronous reactance
equal to the synchronous reactance
inversely proportional to the synchronous reactance
The standard full-load power factor ratings for synchronous motors are
unity or 0.8 leading
zero or 0.8 leading
unity or 0.8 lagging
unity or zero
unity or 0.8 leading
Slip rings are usually made of
copper or aluminium
silver or gold
carbon or graphite
brass or steel
brass or steel
An over excited synchronous motor is used for
fluctuating loads
variable speed loads
power factor corrections
low torque loads
power factor corrections
When the voltage applied to a synchronous motor is increased which of the following will reduce ?
None of the above
Both and
Pull in torque
Stator flux
None of the above
To limit the operating temperature an electrical machine should have proper
current rating
power factor
voltage rating
speed
current rating
A synchronous machine with large air gap has
a higher synchronizing power which makes the machine less sensitive to load variations
all of the above
a higher value of stability limit
a small value of inherent regulation
all of the above
In a synchronous motor running with fixed excitation when the load is increased three times its torque angle becomes approximately
thrice
one-third
twice
six times
thrice
पोस्ट अच्छी लगी हो तो प्लीज नीचे दिए गए लिंक पर क्लिक कर शेयर जरुर करें
0 Comments