Electrical Machines In case of induction motors the ratio of length to pole pitch for minimum cost, is taken as 1.0. 1.5 to 2. 3 to 5. 2 to 3. 1.0. 1.5 to 2. 3 to 5. 2 to 3. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If the applied voltage of a certain transformer is increased by 50% and the frequency is reduced by 50%, the maximum flux density will (assuming that the magnetic circuit remains unsaturated) remain the same as the original changes to 1.5 times the original value changes to three times the original value changes to 0.5 times the original value remain the same as the original changes to 1.5 times the original value changes to three times the original value changes to 0.5 times the original value ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The ventilating ducts in most of DC machine are longitudinal. radial. none of these. radial as well as longitudinal. longitudinal. radial. none of these. radial as well as longitudinal. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines How can the synchronous speed of a 3 - Φ IM be varied? By varying the supply frequency. By varying number of poles. Both (A) and (B). By varying supply voltage. By varying the supply frequency. By varying number of poles. Both (A) and (B). By varying supply voltage. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The brush-axis of a bipolar dc motor is rotated by 90°. The effect of this rotation on the back emf Eband the torque developed Tdwould be such that Eb is zero, but Td is unchanged both Eb and Td are unchanged Eb is unchanged, but Td is zero both Eb and Td are zero Eb is zero, but Td is unchanged both Eb and Td are unchanged Eb is unchanged, but Td is zero both Eb and Td are zero ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The oscillation in a synchronous motor can be damped out by providing damper bars in the rotor pole faces. oscillation cannot be damped. maintaining constant excitation. running the motor on leading power factors. providing damper bars in the rotor pole faces. oscillation cannot be damped. maintaining constant excitation. running the motor on leading power factors. ANSWER DOWNLOAD EXAMIANS APP
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