Electrical Machines A shunt generator has a critical field resistance of 300 Ω at a speed of 800 rpm if the speed is raised to 1000 rpm the critical field resistance is 150 Ω. 145 Ω. 225 Ω. 375 Ω. 150 Ω. 145 Ω. 225 Ω. 375 Ω. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The crawling in the induction motor is caused by harmonics developed in the motor low voltage supply high loads improper design of stator laminations harmonics developed in the motor low voltage supply high loads improper design of stator laminations ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines For the purpose of starting an induction motor, star/delta switch is an equivalent to auto transformer of ratio 50% 57.7% 66.3% 33.3% 50% 57.7% 66.3% 33.3% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A delta/star transformer is connected in parallel to a star/delta transformer. The turn ratio former is x times latter, the x is 1/√3 √3 3 1/3 1/√3 √3 3 1/3 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider the following statements regarding the magnetization characteristics of a dc generator : 1. It represents the variation of field flux with field current. 2. Variation of open-circuit terminal voltage with field current is independent of speed 3. It is non-linear from zero to rated field current 4. It helps to determine the critical field resistance at a given speed 5. It always starts from the origin Which of these statements are correct ? 3 and 5 1, 2 and 5 2, 3 and 4 1 and 4 3 and 5 1, 2 and 5 2, 3 and 4 1 and 4 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Torque angle of a synchorous machine operating from a constant voltage bus is usually defined as the space angle between Stator mmf wave and resultant flux density. Stator mmf wave and resultant mmf wave. Rotor mmf wave and resultant flux density wave. Rotor mmf wave and stator mmf wave. Stator mmf wave and resultant flux density. Stator mmf wave and resultant mmf wave. Rotor mmf wave and resultant flux density wave. Rotor mmf wave and stator mmf wave. ANSWER DOWNLOAD EXAMIANS APP
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