Synchronous motor operation?
A) The supply frequency
B) The speed at which it would run if it operated at a frequency of 55Hz
Answer:
on ac motors in general the sync speed is equal to the 120 x frequency divided by # of poles
RPMsync = 120 x frequency / #poles
450 = 120 x frequency / 16
frequency = 60
@ 55 hz the speed would be 412.5
there is no factor for slip ratio in a synchronous motor, it runs at sync speed, the only thing will be the ammount of rotor lag behind the stator as a function of torque until reaching motor limits, beyond which it will break synchronization and cause possible damage to the motor.
http://www.aosmithmotors.com/html/motord...
A) The frequency times 60 = rpm times number of pole pairs.
therefore the frequency = (450 X 8)/60
= 60hz
Note pole pairs used not poles and frequency is times 60 to convert to revs per second
B) (55 X 60)/8 = rpm
412.5
both of the two people above are correct in their formula,
one uses 120f/no. of poles, the other uses (60)f/pole pairs
which are equal, besides poles are always pair in either motor or generator windings.
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