A 480 V, 60 Hz, 400 hp synchronous motor with a power factor of 0.8 in lead, with eight poles, connected in D, has a synchronous reactance of 0.6 V and negligible resistance in the armature. Ignore friction losses, by friction with the air and in the core
A 480 V, 60 Hz, 400 hp synchronous motor with a power factor of 0.8 in
lead, with eight poles, connected in D, has a synchronous reactance of 0.6 V and
negligible resistance in the armature. Ignore friction losses,
by friction with the air and in the core
a) What is the speed of this motor?
b) Draw the phasor diagram of the motor with an initial load of 200 HP and find
the values of Ia, lL and EA:
c) Assume the shaft load is increased to 400 horsepower rating.
Find lA, IL, and EA after the change in charge. What is the new factor of
engine power? Draw the phasor diagram reaction in response to this
change.
d) What is the torque developed by the synchronous motor at 200 HP and 400 HP
e) What is the maximum torque developed by the synchronous motor?
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