Electrical Machines DC motors are stopped by opening line switches and not by forcing the handle of the motor starter back to OFF position. This is due to occurance of Heavy sparking at the first stud of starting resistance steps. None of these. Both of above. Heavy sparking at brushes. Heavy sparking at the first stud of starting resistance steps. None of these. Both of above. Heavy sparking at brushes. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Series generators are used in which of the following applications? Air crafts. All of these Arc welding. Used as boosters in dc distribution or transmission. Air crafts. All of these Arc welding. Used as boosters in dc distribution or transmission. 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 2, 3 and 4 are correct 1, 2 and 4 are correct 1, 2 and 3 are correct 1 and 4 are correct 2, 3 and 4 are correct 1, 2 and 4 are correct 1, 2 and 3 are correct ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a 3 - φ induction motor running at full load which of these parameters is stationary with respect to the stator mmf wave? Both rotor and stator winding. Rotor winding. Rotor mmf wave. Stator winding. Both rotor and stator winding. Rotor winding. Rotor mmf wave. Stator winding. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a 3 - Φ wound rotor induction motor the short circuit gear is used to short circuit the starting resistance in the starter. stator phases of the motor. None of these rotor at slip rings. starting resistance in the starter. stator phases of the motor. None of these rotor at slip rings. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines To avoid formation of grooves in the commutator the brushes of opposite polarity should track each other. the brushes of same polarity should track each other. None of these brush position has no effect on the commutator grooving. the brushes of opposite polarity should track each other. the brushes of same polarity should track each other. None of these brush position has no effect on the commutator grooving. ANSWER DOWNLOAD EXAMIANS APP
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