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 lagging power factor with over-excitation no change of power factor leading power factor with over-excitation leading power factor with under-excitation lagging power factor with over-excitation no change of power factor leading power factor with over-excitation leading power factor with under-excitation ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors An over excited synchronous motor is used for Power factor corrections Low torque loads Variable speed loads Fluctuating loads Power factor corrections Low torque loads Variable speed loads Fluctuating loads ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors In a 3-phase synchronous motor, the negative phase sequence exists when the motor is None of these under-loaded supplied with unbalanced voltage over-loaded None of these under-loaded supplied with unbalanced voltage over-loaded ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors When pull-out torque occurs in a synchronous motor, the poles of the rotor are _______ Mid way between N and S poles of stator None of the listed here 45° (electrical) behind stator poles Coincident with statorbpoles Mid way between N and S poles of stator None of the listed here 45° (electrical) behind stator poles Coincident with statorbpoles ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors If one phase of a 3 phase synchronous motor is short circuited, motor Will fail to pull into step Will overheat in spots Will refused ro start Will not come upto speed Will fail to pull into step Will overheat in spots Will refused ro start Will not come upto speed ANSWER DOWNLOAD EXAMIANS APP
Synchronous Motors By which of the following methods the constant speed of a synchronous motor can be changed to new fixed value ? By interchanging any two phases By changing the applied voltage By changing the supply frequency By changing the load By interchanging any two phases By changing the applied voltage By changing the supply frequency By changing the load ANSWER DOWNLOAD EXAMIANS APP
EXAMIANS