Electrical Machines If the full load speed of 3-phase, 50Hz induction motor is 950 rpm, what is its half load speed nearly equals to? 975 rpm 940 rpm 1000 rpm 950 rpm 975 rpm 940 rpm 1000 rpm 950 rpm ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Ward-Leonard system for controlling the speed of a DC motor is used where The accuracy in speed control is required. All of above. Very fine speed control over the whole range from zero to normal speed is required. The speed in both the direction is required. The accuracy in speed control is required. All of above. Very fine speed control over the whole range from zero to normal speed is required. The speed in both the direction is required. 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, 2, 3, 4 and 5 2, 3, 4, 5 1, 3, 4, 5 2, 3, 4 1, 2, 3, 4 and 5 2, 3, 4, 5 1, 3, 4, 5 2, 3, 4 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The armature of DC machine is made of silicon steel lamination to increase the permeability. reduce hysteresis loss only. reduce both eddy current and hysteresis loss. reduce eddy current loss only. increase the permeability. reduce hysteresis loss only. reduce both eddy current and hysteresis loss. reduce eddy current loss only. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In 3 - Φ induction motor some times copper bars are placed deep in the rotor to improve power factor. reduce copper loss. improve efficiency. improve starting torque. improve power factor. reduce copper loss. improve efficiency. improve starting torque. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Unbalanced supply voltage given to a 3 - φ, delta connected induction motor will cause less heating of the rotor. all of these. negative sequence current. less heating of the rotor. less heating of the rotor. all of these. negative sequence current. less heating of the rotor. ANSWER DOWNLOAD EXAMIANS APP
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