Electrical Machines What is the necessity of copper brushes in a dc motors? To absorb the mechanical shocks produced during running condition. To increase the flux cutting by the rotor. None of these. To convert alternating supply current to direct current. To absorb the mechanical shocks produced during running condition. To increase the flux cutting by the rotor. None of these. To convert alternating supply current to direct current. 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, 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 1, 2, 3, 4 and 5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a DC Shunt Motor if the load current increases then field flux decreases increases. decreases. remains constant. decreases increases. decreases. remains constant. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In the 3-phase induction motor, the resultant flux is of a constant nature and is 3/2 times maximum value of flux due to any phase equal to φm, where φm is the maximum flux due to any phase 1/2 times maximum value of flux due to any phase 3 times maximum value of flux due to any phase 3/2 times maximum value of flux due to any phase equal to φm, where φm is the maximum flux due to any phase 1/2 times maximum value of flux due to any phase 3 times maximum value of flux due to any phase ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a DC motor under constant terminal voltage what is the relation between torque (Te) and power (P) T∝ P² T∝ P³ T is independent of P T∝ P T∝ P² T∝ P³ T is independent of P T∝ P ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines As compared to DOL starting, a cage induction motor with star-delta starting shall have reduced starting current. more starting time. more starting torque. smoother acceleration. reduced starting current. more starting time. more starting torque. smoother acceleration. ANSWER DOWNLOAD EXAMIANS APP
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