Electrical Machines Which of the following transformer insulating oil generally used in India? Olefin based insulating oil. Aromatics based insulating oil. Naphtha based insulating oil. Paraffin based insulating oil. Olefin based insulating oil. Aromatics based insulating oil. Naphtha based insulating oil. Paraffin based insulating oil. 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%. 960 RPM 970 RPM 940 RPM 920 RPM 960 RPM 970 RPM 940 RPM 920 RPM ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Slip speed is the difference of actual rotor speed and synchronous speed. half of the sum of synchronous and rotor speeds. difference of synchronous speed and actual rotor speed. sum of synchronous and rotor speeds. difference of actual rotor speed and synchronous speed. half of the sum of synchronous and rotor speeds. difference of synchronous speed and actual rotor speed. sum of synchronous and rotor speeds. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Two transformers with identical rating, are designed with flux densities of 1.2 and 1.4 Wb / m2 respectively. The weight of first transformer per kVA is equal to that of second transformer. less than that of second transformer. none of these. more than that of second transformer. equal to that of second transformer. less than that of second transformer. none of these. more than that of second transformer. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If the back emf in DC motor vanishes suddenly the motor will run at very low speed. burn. start haunting. run at very high speed. run at very low speed. burn. start haunting. run at very high speed. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following is/are not a self starting motor? None of these 1-phase induction motor 3-phase induction motor both 1 and 2 None of these 1-phase induction motor 3-phase induction motor both 1 and 2 ANSWER DOWNLOAD EXAMIANS APP
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