Synchronous Motors The operating speed of a synchronous motor can be changed to new fixed value by changing frequency changing the load using brakes changing the supply voltage changing frequency changing the load using brakes changing the supply voltage ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors The efficiency of a properly designed synchronous motor will usually fall in range 85 to 95% 99 to 99.5% 75 to 80% 60 to 70% 85 to 95% 99 to 99.5% 75 to 80% 60 to 70% ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors The minimum armature current of the synchronous motor corresponds to operation at zero power factor leading 0.707 power factor lagging 0.707 power factor leading unity power factor zero power factor leading 0.707 power factor lagging 0.707 power factor leading unity power factor ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors Damper winding in a synchronous motor________ Reduces windage losses Improve pf of the motor Increases hunting of the motor Serves to start the motor Reduces windage losses Improve pf of the motor Increases hunting of the motor Serves to start the motor ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors If the field circuit of an unloaded salientpole synchronous motor gets suddenly open-circuited, then it runs at a very high speed it runs at a slower speed the motor stops it continues to run at the same speed it runs at a very high speed it runs at a slower speed the motor stops it continues to run at the same speed ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors In case one phase of a three-phase synchronous motor is short-circuited the motor will run at 2/3 of synchronous speed take less than the rated load not start run with excessive vibrations run at 2/3 of synchronous speed take less than the rated load not start run with excessive vibrations ANSWER DOWNLOAD EXAMIANS APP
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