Electrical Machines A commutator with a diameter of 50 cm rotating at 1000 rpm. For a brush width of 1.5 cm, find the time of commutation in ms. 0.573. 0.443. 0.649. 0.512. 0.573. 0.443. 0.649. 0.512. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The armature mmf of a DC machine has trapezoidal space distribution and is stationary in space. triangular space distribution and rotates at the speed of armature. triangular space distribution and is stationary in space. stepped distribution and rotates at the speed of armature. trapezoidal space distribution and is stationary in space. triangular space distribution and rotates at the speed of armature. triangular space distribution and is stationary in space. stepped distribution and rotates at the speed of armature. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following is/are effects of armature reaction? increase the iron loss All of these increases the design cost increase the maintenance and repair increase the iron loss All of these increases the design cost increase the maintenance and repair ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following are variable losses? hysteresis loss eddy current loss armature copper loss shunt field copper loss hysteresis loss eddy current loss armature copper loss shunt field copper loss ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A lap wound DC machine has 400 conductors and 8 poles. The voltage induced per conductor is 2 volts. The machine generates a voltage of 800 V. 200 V. 400 V. 100 V. 800 V. 200 V. 400 V. 100 V. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 3-φ alternator has negligible stator resistance. A short circuit test is conducted on this alternator. At a particular speed, a field current of If1 is required to drive the rated armature current. If the speed of the alternator is reduced to half, the field current required to maintain rated armature current Would be equal to If1/2. Woud be equal to 2If1. Cannot be predicted due to insufficient data. Would be equal to If1. Would be equal to If1/2. Woud be equal to 2If1. Cannot be predicted due to insufficient data. Would be equal to If1. ANSWER DOWNLOAD EXAMIANS APP
EXAMIANS