Electrical Machines Ward-Leonard system for controlling the speed of a DC motor is used where The accuracy in speed control is required. All of above. Very fine speed control over the whole range from zero to normal speed is required. The speed in both the direction is required. The accuracy in speed control is required. All of above. Very fine speed control over the whole range from zero to normal speed is required. The speed in both the direction is required. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The brush-axis of a bipolar dc motor is rotated by 90°. The effect of this rotation on the back emf Eband the torque developed Tdwould be such that both Eb and Td are zero Eb is zero, but Td is unchanged both Eb and Td are unchanged Eb is unchanged, but Td is zero both Eb and Td are zero Eb is zero, but Td is unchanged both Eb and Td are unchanged Eb is unchanged, but Td is zero ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Neglecting all losses, the developed torque (T) of DC separately excited motor, operating under constant terminal voltage is reduced to its output power (P) as T ∝ √P. T2 ∝ P3. T ∝ P. T is independent of P. T ∝ √P. T2 ∝ P3. T ∝ P. T is independent of P. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines What is power factor of a 3 - φ induction motor at no load? Equal to 1. Same as full load. Low. High. Equal to 1. Same as full load. Low. High. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In 3 - Φ induction motor some times copper bars are placed deep in the rotor to reduce copper loss. improve power factor. improve efficiency. improve starting torque. reduce copper loss. improve power factor. improve efficiency. improve starting torque. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines An inverted V-curve of synchronous motor shows the variation of All of these supply voltage and field current at constant excitation power factor and dc excitation at constant load power factor and supply voltage during hunting All of these supply voltage and field current at constant excitation power factor and dc excitation at constant load power factor and supply voltage during hunting ANSWER DOWNLOAD EXAMIANS APP
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