Electrical Machines In travelling cranes for hoisting and lowering which type of motor is preferred? DC series motor. AC slip ring motor. Single phase induction motor. Synchronous motor. DC series motor. AC slip ring motor. Single phase induction motor. Synchronous motor. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following factors improve commutation in a dc machine ? 1. High contact resistance of brushes 2. High inductance of the coils undergoing commutation 3. Shifting of brushes in the direction of rotation for a generator and in the opposite direction For a motor 4. Narrow width for the commutation bars Select the correct answer using the codes given below : Codes : 1, 2, and 3 1 and 3 1, 2 and 4 2, 3 and 4 1, 2, and 3 1 and 3 1, 2 and 4 2, 3 and 4 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider the following statements : 1. interpole windings are connected in series with armature windings 2. polarity of interpoles must be the same as that of the main poles in advance 3. distortion of the main field under the pole shoes is not affected by the use of interpoles From above, the correct answer is 1 and 2 2 and 3 1 and 3 1 alone 1 and 2 2 and 3 1 and 3 1 alone ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In shaded pole induction motors, the flux moves from ------------- region to ----------------- region respectively? shaded, unshaded unshaded, shaded shaded, shaded unshaded, unshaded shaded, unshaded unshaded, shaded shaded, shaded unshaded, unshaded ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Poles of DC machine are often laminated to dissipate more heat. reduce iron weight. reduce pulsation loss. reduce armature reaction. dissipate more heat. reduce iron weight. reduce pulsation loss. reduce armature reaction. 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 2, 3, 4 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 ANSWER DOWNLOAD EXAMIANS APP
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