Electrical Machines The sparking at the the brushes, in a DC machines is due to reactance voltage. presence of commutator. armature reaction. high resistance of carbon brushes. reactance voltage. presence of commutator. armature reaction. high resistance of carbon brushes. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A smaller air gap in a polyphase induction motor helps to increase the starting torque. reduce the chance of cogging. reduce the chance of crawling. reduce the magnetizing current. increase the starting torque. reduce the chance of cogging. reduce the chance of crawling. reduce the magnetizing current. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a synchronous machine, if φ is the flux per pole and f is the frequency of the emf induced E then E ∝ f/φ E ∝ φ/f E ∝ φf E ∝ 1/(φf) E ∝ f/φ E ∝ φ/f E ∝ φf E ∝ 1/(φf) ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Maximum power developed depends on load angle both 1and 2 voltage reactance load angle both 1and 2 voltage reactance ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Ward-Leonard system for controlling the speed of a DC motor is used where All of above. The speed in both the direction is required. Very fine speed control over the whole range from zero to normal speed is required. The accuracy in speed control is required. All of above. The speed in both the direction is required. Very fine speed control over the whole range from zero to normal speed is required. The accuracy in speed control is required. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 200 V DC machine supplies 20 A at 200 V as a generator. The armature resistance is 0.2 Ω. If the machine is now operated as a motor at same terminal voltage and current but with the flux increased by 10%, the ratio of motor speed to generator speed is 0.96 0.87 0.95 1.06 0.96 0.87 0.95 1.06 ANSWER DOWNLOAD EXAMIANS APP
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