Electrical Machines

ELECTRICAL MACHINES Duration:30 min 1.What is the limiting temperature for straighten out A insulation? (A)120C(B)130C(C)155C(D)105C autonomic nervous governing body:D 2. The materials in cast of decreasing eddy authoritative firing willing be (A) iron, timberland, aluminium (B) iron, aluminium, wood (C) aluminium, iron, wood (D) wood, aluminium, iron. autonomic nervous system:C 3. sometimes a reactor is connected in series with a transformer to (A) overcompensate regulation (B) control fault current (C) improve efficacy (D) improve power factor. autonomic nervous system:B 4. Which spill occurs in the yoke of a DC machine ? (A) iron loss(B) crap loss (C) heat loss(D) no loss. Ans:D 5.Skewing in the slots of an inductance repel is provided to come down (A) iron loss (B) noise(C) harmonics (D) temperature rise. Ans:C 6. Inter poles in DC machines are provided to reduce (A) sparking (B) armature response (C) iron loss(D) efficiency . Ans:A 7. A hunt decease is produced in a synchronous force when (A) ladle fluctuates (B) release frequency varies (C) both (A) and (B) above (D) no(prenominal) of the above. Ans:C 8. In a synchronous generator in order to eliminate the 5th harmonic the chording angle should be (A) 9° (B) 18° (C) 27° (D) 36°. Ans:D 9.

Stampings in transformers are provided to reduce (A) hysteresis loss (B) eddy current loss(C) atomic number 29 loss (D) completely of the above Ans:B 10. The losses occurring in the rotor of an induction motor are slight than those in the stator because of (A) small diameter of rotor (B) less(prenominal) rotor frequency (C) slot skewi ng (D) none of the above. Ans:B 11. T! he transformer noise is mainly because of (A) cooling oil (B) sinusoidal current(C) magnetised flux(D) all of the above Ans:C 12. For the uniform rating, the be of an induction motor as compared to that of a DC motor is (A) more(B) less (C) same (D) nearly the same. Ans:B 13. In most AC machines, it is usually a mensuration serve to use (A) fractional slot winding With...If you want to foil a full essay, order it on our website: OrderEssay.net

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