Electrical Machines What is the mechanical power developed by a DC series motor is maximum? Back emf is equal to zero. Back emf is equal to half the applied voltage. Back emf is equal to applied voltage. None of above. Back emf is equal to zero. Back emf is equal to half the applied voltage. Back emf is equal to applied voltage. None of above. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines It is an advisable to use auto transformer if the transformation ratio is near to 1. Greater than 1. 0.25. 0.5. near to 1. Greater than 1. 0.25. 0.5. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines φA 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 speed when running as a motor taking 40 A at 250 V. Armature reaction weakens the field by 4%. 940 RPM 920 RPM 970 RPM 960 RPM 940 RPM 920 RPM 970 RPM 960 RPM ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Induction motors provided with open slots have less breakdown torque. more breakdown torque. leading power factor. higher efficiency. less breakdown torque. more breakdown torque. leading power factor. higher efficiency. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Saving of copper in auto transformer is increased as compared to two winding transformer, when transformation ratio K approaches to infinity. zero. two. unity. infinity. zero. two. unity. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A DC series motor has which of the following characteristics? Has its field winding consinting of thick wire and less no of turns. Has a almost constant speed. Can be started easily without load. Has a poor torque. Has its field winding consinting of thick wire and less no of turns. Has a almost constant speed. Can be started easily without load. Has a poor torque. ANSWER DOWNLOAD EXAMIANS APP
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