Electrical Machines A 4 pole, 3-phase induction motor is running at 4% slip at full load. If the speed of the motor is 720 rpm, the supply frequency is 40 HZ 50 Hz 25 Hz 60 Hz 40 HZ 50 Hz 25 Hz 60 Hz ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a three phase slip-ring induction motor, brushes are connected to external star-connected resistors. 3 - Φ AC supply. DC supply. equalizing coils. external star-connected resistors. 3 - Φ AC supply. DC supply. equalizing coils. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The rotor of a three phase induction motor has an impedance of 0.4 + j4 ohm per phase at standstill the maximum torque occurs at a slip of _____________. 50 %. 25 %. 10 %. 15 %. 50 %. 25 %. 10 %. 15 %. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The field system of an alternator is usually excited 250 / 250 V DC. 3 - Φ, 50 Hz and 400 V. 230 V AC. 110 / 220 V AC. 250 / 250 V DC. 3 - Φ, 50 Hz and 400 V. 230 V AC. 110 / 220 V AC. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A smaller air gap in a polyphase induction motor helps to reduce the magnetizing current. increase the starting torque. reduce the chance of crawling. reduce the chance of cogging. reduce the magnetizing current. increase the starting torque. reduce the chance of crawling. reduce the chance of cogging. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A DC series motor must started on no load because it would Not develop starting torque. Fail to start without load. Run at dangerously high speed. Draw more current without producing sufficient torque. Not develop starting torque. Fail to start without load. Run at dangerously high speed. Draw more current without producing sufficient torque. ANSWER DOWNLOAD EXAMIANS APP
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