Electrical Machines In case of a dc motor the ratio Eb / E is indicative of ratio of starting to running current. efficiency. ratio of input to output voltage. ratio of starting to running torque. ratio of starting to running current. efficiency. ratio of input to output voltage. ratio of starting to running torque. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines For satisfactory parallel operation of two transformers which of the following conditions is most essential, polarities of all transformers must be same. voltage ratio of all transformers must be same. percentage impedance of all transformers must be same. MVA rating of all transformer inversely proportional to impedance. polarities of all transformers must be same. voltage ratio of all transformers must be same. percentage impedance of all transformers must be same. MVA rating of all transformer inversely proportional to impedance. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The crawling in the induction motor is caused by improper design of stator laminations low voltage supply harmonics developed in the motor high loads improper design of stator laminations low voltage supply harmonics developed in the motor high loads ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines When the mechanical power is developed by a DC motor maximum None of above. back emf is equal to applied voltage. Back emf is equal to half of applied voltage. Back emf is equal. None of above. back emf is equal to applied voltage. Back emf is equal to half of applied voltage. Back emf is equal. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider the following statements : Interpoles in dc machines 1. reducearmature reaction effects in the interpolar region 2. have the same dimension as main polls 3. have their windings connected in series with the armature 4. have same number of turns as the armature 5. have the polarity same as that of the main pole ahead in a motor From these, the correct statements are 1, 3 and 5 1, 2 and 3 1, 2, 3 and 5 1 and 3 1, 3 and 5 1, 2 and 3 1, 2, 3 and 5 1 and 3 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. two. unity. zero. infinity. two. unity. zero. ANSWER DOWNLOAD EXAMIANS APP
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