Electrical Machines A cumulatively compounded dc motor delivers rated load power at rated speed. If the series field is short-circuited, then Ia remains constant but ωm increase Ia increases and ωm decreses both decrese both armature current Ia and speed ωm increase Ia remains constant but ωm increase Ia increases and ωm decreses both decrese both armature current Ia and speed ωm increase ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A DC series motor is running at rated speed without any additional resistance in series. If an additional resistance is placedin series, the speed of motor Remains unchanged. Decreases. Oscillates around the rated speed. Increases. Remains unchanged. Decreases. Oscillates around the rated speed. Increases. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The armature reaction mmf in a DC machines has a form of rectangular. trapezoidal. triangular. sinusoidal. rectangular. trapezoidal. triangular. sinusoidal. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a loaded DC motor, if the brushes are given a shift from the interpolar axis in the direction of rotation, then the commutation will improve and the speed rises. improve and the speed falls. deteriorate and the speed rises. deteriorate and the speed falls. improve and the speed rises. improve and the speed falls. deteriorate and the speed rises. deteriorate and the speed falls. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Transformer action requires a increasing magnetic flux. constant magnetic flux. alternating electric flux. alternating magnetic lux. increasing magnetic flux. constant magnetic flux. alternating electric flux. alternating magnetic lux. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The introduction of interpoles in between the main poles improves the performance of a dc machine, because the interpoles produce additional flux to augment the developed torque the flux waveform is improved with reduction in harmonics the inequality of air-gap flux on the top and bottom halves of the armature is removed a counter-emf is induced in the coil undergoing commutation the interpoles produce additional flux to augment the developed torque the flux waveform is improved with reduction in harmonics the inequality of air-gap flux on the top and bottom halves of the armature is removed a counter-emf is induced in the coil undergoing commutation ANSWER DOWNLOAD EXAMIANS APP
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