Electrical Machines A commutator with a diameter of 50 cm rotating at 1000 rpm. For a brush width of 1.5 cm, find the time of commutation in ms. 0.649. 0.573. 0.443. 0.512. 0.649. 0.573. 0.443. 0.512. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Armature reaction in a DC machine is in direct opposition to the main poles. makes an angle of 90° with the main pole axis. makes an angle with the main pole axis which is load dependent. is in the same direction as the main poles. is in direct opposition to the main poles. makes an angle of 90° with the main pole axis. makes an angle with the main pole axis which is load dependent. is in the same direction as the main poles. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following represents the commutator pitch? 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 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. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The brushes of a DC machine should be placed on the armature midway between poles. commutator in the polar axis. commutator in the inter polar axis. armature in the polar axis. armature midway between poles. commutator in the polar axis. commutator in the inter polar axis. armature in the polar axis. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines DC series motor is best suited for electric traction as It is cheaper in cost. It develops high starting torque. It consume less power. It runs at very high speed at light load. It is cheaper in cost. It develops high starting torque. It consume less power. It runs at very high speed at light load. 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 2, 3, 4, 5 1, 2, 3, 4 and 5 2, 3, 4 1, 3, 4, 5 2, 3, 4, 5 1, 2, 3, 4 and 5 2, 3, 4 ANSWER DOWNLOAD EXAMIANS APP
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