a) Tf/Tmax =2a/(a2 + s2) b) Tf/Tmax =2/(a2 + s2) c) Tf/Tmax =2as/(a2 + s2) d) Tf/Tmax =a/(a2 + s2) Ans: (c)
Where s is the slip and a = R2/X2 = (Resistance of the rotor)/(Resistance of the rotor)
a) Ts/Tmax = 2a/(1 + a2 ) b) Ts/Tmax = 2a/(S2 + a2 ) c) Ts/Tmax = 2/(1 + s2 ) d) Ts/Tmax = 2a/(S2 + 1) Ans: (a)
a) True b) False Ans: (a)
a) Star connected only b) Delta connected only c) (a) and (b) both d) None of the above Ans: (c)
a) K × torque with direct switching b) K/ torque with direct switching c) K2 × torque with direct switching d) K2/torque with direct switching Ans: (c)
Where tapping of transformation ratio K is used in case of auto-transformer.
a) 70% b) 71% c) 71.5% d) 72.2% Ans: (d)
When the short circuit current on normal voltage is 4 times the full load and full load slip is 30%.
a) 57% b) 56.5% c) 86.6% d) 58% approximately Ans: (d)
a) True b) False Ans: (b)
a) True b) False Ans: (a)
a) Improper design of the machine b) Low voltage supply c) High Loads d) Harmonics developed in the motor Ans: (d)
a) True b) False Ans: (b)
a) True b) False Ans: (b)
a) True b) False Ans: (a)
a) In parallel b) In series parallel c) In series d) In parallel with stator Ans: (a)
a) True b) False Ans: (b)