21. A pump induction motor is switched on to a supply 30% lower than its rated voltage. The pump runs. What will eventually happen? It will . . . . . . . . .? A. Stall after sometime B. Stall immediately C. Continue to run at lower speed without damage D. Get heated and subsequently get damaged Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option D No explanation is given for this question Let's Discuss on Board
22. The circle diagram for an induction motor cannot be used to determine A. Efficiency B. Power factor C. Frequency D. Output Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option A No explanation is given for this question Let's Discuss on Board
23. Short-circuit test on an induction motor cannot be used to determine A. Windage losses B. Copper losses C. Transformation ratio D. Power scale of circle diagram Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option A No explanation is given for this question Let's Discuss on Board
24. The torque of a rotor in an induction motor under running condition is maximum A. At the unit value of slip B. At the zero value of slip C. At the value of the slip which makes rotor reactance per phase equal to the resistance per phase D. At the value of the slip which makes the rotor reactance half of the rotor Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option C No explanation is given for this question Let's Discuss on Board
25. What will happen if the relative speed between the rotating flux of stator and rotor of the induction motor is zero? A. The slip of the motor will be 5% B. The rotor will not run C. The rotor will run at very high speed D. The torque produced will be very large Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option B No explanation is given for this question Let's Discuss on Board
26. In three-phase induction motors sometimes copper bars are placed deep in the rotor to A. Improve starting torque B. Reduce copper losses C. Improve efficiency D. Improve power factor Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option A No explanation is given for this question Let's Discuss on Board
27. The speed characteristics of an induction motor closely resemble the speed-load characteristics of which of the following machines A. D.C. series motor B. D.C. shunt motor C. Universal motor D. None of the above Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option B No explanation is given for this question Let's Discuss on Board
28. Step-less speed control of induction motor is possible by which of the following methods? A. e.m.f. injection in rotor eueuit B. Changing the number of poles C. Cascade operation D. None of the above Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option B No explanation is given for this question Let's Discuss on Board
29. The starting torque of a 3 phase squirrel cage induction motor is A. Twice the full load torque B. 1.5 times the full load torque C. Equal to full load torque D. Any of the above Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option B No explanation is given for this question Let's Discuss on Board
30. When the equivalent circuit diagram of double squirrel-cage induction motor is constructed the two cages can be considered A. In series B. In parallel C. In series-parallel D. In parallel with stator Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option B No explanation is given for this question Let's Discuss on Board
