Electrical Machines What is the phase difference between two windings of A.C servomotor ? 90°. 120°. 60°. 30°. 90°. 120°. 60°. 30°. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider a separately excited DC motor. If the field current is increased while the armature terminal voltage is held constant, then speed of the motor will remains same. none of these. Decrease.d increase. remains same. none of these. Decrease.d increase. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A synchronous motor is supplying a load at unity power factor. If the load on the motor is increased keeping its excitation and terminal voltage constant, the power factor will become leading will become lagging None of these will remain the same will become leading will become lagging None of these will remain the same ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider the following statements about commutating poles which are fitted on most large dc Shunt motors: 1. The commutating poles are placed in the geometric neutral plane and their number is usually Equal to the number of main poles 2. The winding on the commutating poles is connected in series with the shunt-field winding on the main poles 3. The polarity of the commutating pole must be that of the next pole further ahead 4. The commutating poles neutralize the reactance voltage produced in the coil undergoing Commutation. Of these statements, 1 and 4 are correct 1, 2 and 4 are correct 1, 2 and 3 are correct 2, 3 and 4 are correct 1 and 4 are correct 1, 2 and 4 are correct 1, 2 and 3 are correct 2, 3 and 4 are correct ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The change in speed of a DC generator due to increased load is corrected by increasing armature resistance. increasing armature cooling. increasing input power of the prime mover. increasing terminal voltage. increasing armature resistance. increasing armature cooling. increasing input power of the prime mover. increasing terminal voltage. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Unbalance 3 - Φ stator currents cause All of these vibrations. heating of rotor. double frequency currents in the rotor. All of these vibrations. heating of rotor. double frequency currents in the rotor. ANSWER DOWNLOAD EXAMIANS APP
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