Electrical Machines The heat transfer by convection in a transformer least depends on air velocity. temperature difference. surface area. color of the paint. air velocity. temperature difference. surface area. color of the paint. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a DC generator, if P be the number of poles and N be the rpm of the rotor, then frequency of magnetic reversals will be PN/120. PN/2. PN/3000. PN/60. PN/120. PN/2. PN/3000. PN/60. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines R1 is the resistance of the primary winding of the transformer. The turn ratio in terms of primary to secondary is K. Then the equivalent resistance of the primary referred to secondary is K²R1 K×R1 R1 /K² R1 /K K²R1 K×R1 R1 /K² R1 /K 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 The principal of starting of 3 - Φ IM is similar to synchronous motor. capacitor run IM. transformer with short-circuited secondary. repulsion motor type starting. synchronous motor. capacitor run IM. transformer with short-circuited secondary. repulsion motor type starting. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The torque angle, in a synchronous motor, is the angle between the rotating stator flux and rotor flux. the supply voltage and the back emf. None of these magnetizing electric current and back emf. the rotating stator flux and rotor flux. the supply voltage and the back emf. None of these magnetizing electric current and back emf. ANSWER DOWNLOAD EXAMIANS APP
EXAMIANS