Synchronous Motors 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 no change of power factor leading power factor with under-excitation leading power factor with over-excitation lagging power factor with over-excitation no change of power factor leading power factor with under-excitation leading power factor with over-excitation lagging power factor with over-excitation ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors In a synchronous motor, the maximum power developed depends on all of the following except direction of rotation maximum value of coupling angle rotor excitation supply voltage direction of rotation maximum value of coupling angle rotor excitation supply voltage ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors The pull out torque of a practical synchronous motor will occur when the torque angle is about _____ 0° 30° 45° 75° 0° 30° 45° 75° ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors A synchronous motor will always stop when Excitation winding gets disconnected Load in motor varies Supply voltage frequency changes Supply voltage fluctuates Excitation winding gets disconnected Load in motor varies Supply voltage frequency changes Supply voltage fluctuates ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors Damper winding in a synchronous motor________ Increases hunting of the motor Reduces windage losses Improve pf of the motor Serves to start the motor Increases hunting of the motor Reduces windage losses Improve pf of the motor Serves to start the motor ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors The efficiency of a properly designed synchronous motor will usually fall in range 99 to 99.5% 60 to 70% 75 to 80% 85 to 95% 99 to 99.5% 60 to 70% 75 to 80% 85 to 95% ANSWER DOWNLOAD EXAMIANS APP
EXAMIANS