Electrical Machines If peak value of phase mmf is F max , then peak value of the rotating field caused by three phase is (1/2)Fmax. Fmax. (3/2)Fmax. 3Fmax. (1/2)Fmax. Fmax. (3/2)Fmax. 3Fmax. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Direct-on-line (DOL) starters are not suitable for starting large DC motors, because the motor may not start. the starting current will be enormously high. the starting torque becomes low. the motor may run away. the motor may not start. the starting current will be enormously high. the starting torque becomes low. the motor may run away. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider a separately excited DC motor. If the field current is increased while the armature terminal voltage is held constant, then speed of the motor Remains same. Increase. None of these. Decrease. Remains same. Increase. None of these. Decrease. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 500 V, 120 KW, 50 Hz, star connected synchronous motor operating at 0.8 power factor leading has full load efficiency of 91%. The armature resistance is equal to 0.08Ω. The magnitude of armature current is nearly equal to 173 A. 190 A. 240 A. 127 A. 173 A. 190 A. 240 A. 127 A. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 3 - Φ, 4 pole, 50 Hz induction motor 4 % slip, calculate frequency of the rotor emf? 50 Hz. 3 Hz. 2 Hz. 10 Hz. 50 Hz. 3 Hz. 2 Hz. 10 Hz. ANSWER DOWNLOAD EXAMIANS APP
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. 0.443. 0.573. 0.512. 0.649. 0.443. 0.573. 0.512. 0.649. ANSWER DOWNLOAD EXAMIANS APP
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