Electrical Machines A 4 pole DC generator runs at 750 rpm and generate an emf of 240 V. The armature is wave wound and has 792 conductors. If the total flux from each pole is 0.0145 Wb. What is the leakage co-efficient? 1.8. 1.5. 1.4. 1.2. 1.8. 1.5. 1.4. 1.2. 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
Electrical Machines In 3 - Φ induction motor some times copper bars are placed deep in the rotor to reduce copper loss. improve starting torque. improve efficiency. improve power factor. reduce copper loss. improve starting torque. improve efficiency. improve power factor. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Hunting in a synchronous cannot be due to windage friction. variable frequency. variable load. variable supply voltage. windage friction. variable frequency. variable load. variable supply voltage. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Ward-Leonard system for controlling the speed of a DC motor is used where All of above. The accuracy in speed control is required. Very fine speed control over the whole range from zero to normal speed is required. The speed in both the direction is required. All of above. The accuracy in speed control is required. 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 If the load current and the flux of a DC motor are held constant and voltage applied across its armature is increased by 5%, the speed of the motor will reduce by 5 %. depend on other factors. remain unchanged. increase by 5 %. reduce by 5 %. depend on other factors. remain unchanged. increase by 5 %. ANSWER DOWNLOAD EXAMIANS APP
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