Electrical Machines The synchronous motor can be started by coupling it with a DC compound motor. coupling it with a small AC induction motor called the pony motor. providing damper winding in its rotor circuit. any of the above methods. coupling it with a DC compound motor. coupling it with a small AC induction motor called the pony motor. providing damper winding in its rotor circuit. any of the above methods. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines It is advisable to start a DC series motor with some load to Limit the speed. Limit the flux. Limit the current. Avoid sparking. Limit the speed. Limit the flux. Limit the current. Avoid sparking. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a DC motor under constant terminal voltage what is the relation between torque (Te) and power (P) T is independent of P T∝ P³ T∝ P T∝ P² T is independent of P T∝ P³ T∝ P T∝ P² ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A DC shunt machine generates 250 V on open circuit at 1000 RPM. Armature resistance is 0.5 Ω, field resistance 250 Ω. When running as a motor takes 4 A at 250 V. Calculate the efficiency when running as a motor taking 40 A at 250 V. Armature reaction weakens the field by 4%. 72.5% 82.5% 67.5% 78.5% 72.5% 82.5% 67.5% 78.5% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 3 - Φ, 400 / 200 V, Y - Y connected wound rotor induction motor has 0.06 Ω rotor resistance and 0.3 Ω standstill reactance per phase. To make the starting torque equal to maximum torque of the motor the additional resistance required 0.66 Ω. 0.24 Ω. 0.78 Ω. 0.45 Ω. 0.66 Ω. 0.24 Ω. 0.78 Ω. 0.45 Ω. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider the following statements: To control the speed of a dc shunt motor above the base speed over a reasonably wide range, the motor must 1. have compensating winding 2. have interpole winding 3. be started using a 3-point starter 4. be started using a 4-point starter Of these statements 1, 2 and 3 are correct 1, 2 and 4 are correct 1 and 3 are correct 2 and 4 are correct 1, 2 and 3 are correct 1, 2 and 4 are correct 1 and 3 are correct 2 and 4 are correct ANSWER DOWNLOAD EXAMIANS APP
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