Electrical Machines With the increases in field excitation of a DC generator, its generated emf decreases. increases. remains constant. increases upto a limit and then remains almost constant. decreases. increases. remains constant. increases upto a limit and then remains almost constant. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The mechanical power is developed by a DC motor is maximum when back emf is equal to half of applied voltage. back emf is equal to twice of applied voltage. none of above. back emf is equal to applied voltage. back emf is equal to half of applied voltage. back emf is equal to twice of applied voltage. none of above. back emf is equal to applied voltage. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If an induction machine is run at above the synchronous speed it acts as an induction motor a synchronous motor None of these an induction generator an induction motor a synchronous motor None of these an induction generator 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 1, 3, 4, 5 2, 3, 4 2, 3, 4, 5 1, 2, 3, 4 and 5 1, 3, 4, 5 2, 3, 4 2, 3, 4, 5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The results of a slip test for determining direct axis (Xd) and quadrature axis (Xq) reactances of a star connected salient pole alternator are given below Phase values: Vmax = 108 V ; Vmin = 96 V Imax = 12 A ; Imin = 10 A Hence the two reactances will be Xd = 8Ω and Xq = 10.8Ω Xd = 9Ω and Xq = 9.6Ω Xd = 9.6Ω and Xq = 9Ω Xd = 10.8Ω and Xq = 8Ω Xd = 8Ω and Xq = 10.8Ω Xd = 9Ω and Xq = 9.6Ω Xd = 9.6Ω and Xq = 9Ω Xd = 10.8Ω and Xq = 8Ω ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines For which of the following loads, armature reaction is magnetizing in nature? pure inductive load None of these pure capacitive load pure resistive load pure inductive load None of these pure capacitive load pure resistive load ANSWER DOWNLOAD EXAMIANS APP
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