Electrical Machines What is the mechanical power developed by a DC series motor is maximum? Back emf is equal to applied voltage. None of above. Back emf is equal to half the applied voltage. Back emf is equal to zero. Back emf is equal to applied voltage. None of above. Back emf is equal to half the applied voltage. Back emf is equal to zero. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The following statements relate to compensating winding (CW) and interpole winding (IW) of a dc machine : 1. CW neutralizes the armature reaction under a pole pitch 2. IW is connected in series with armature circuit 3. IW produces mmf in the commutating zone only 4. CWmmf is directed along the brush axis 5. Mmf produced by IW is equal to armature mmf From these, the correct statements are 1, 3, 4, 5 1, 2, 3, 4 and 5 2, 3, 4 2, 3, 4, 5 1, 3, 4, 5 1, 2, 3, 4 and 5 2, 3, 4 2, 3, 4, 5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following represents the commutator pitch? Number of conductors spanned by one coil at the front end of the armature. Number of commutator segments between two successive coils. Number of conductors spanned by one coil at the back end of the armature. The distance between the staring of first coil and its next successive coil Number of conductors spanned by one coil at the front end of the armature. Number of commutator segments between two successive coils. Number of conductors spanned by one coil at the back end of the armature. The distance between the staring of first coil and its next successive coil ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 4 pole, 3-phase induction motor is running at 4% slip at full load. If the speed of the motor is 720 rpm, the supply frequency is 60 Hz 25 Hz 50 Hz 40 HZ 60 Hz 25 Hz 50 Hz 40 HZ ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Torque developed in the rotor is not dependent on the slip inversely proportional to slip directly proportional to slip either of these not dependent on the slip inversely proportional to slip directly proportional to slip either of these ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines To achieve spark less commutation brushes of DC generator are rocked ahead so as to bring them None of these just behind the magnetic neutral axis. in magnetic neutral axis. just ahead of magnetic neutral axis. None of these just behind the magnetic neutral axis. in magnetic neutral axis. just ahead of magnetic neutral axis. ANSWER DOWNLOAD EXAMIANS APP
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