1. The secondary sources of energy are (a) Solar, wind and water (b) Coal, oil and uranium (c) Either (a) or (b) (d) Neither (a) or (b) 2. The draught which a chimney produces is called (a) Induced draught (b) Natural draught (c) Forced draught (d) Balanced draught 3. The draught in locomotive boilers is […]
1. By low voltage application, we can start a: (a) Schrage motor (b) Synchronous motor (c) Slip ring induction motor (d) DC compound motor [UPPCL (JE) – 2016] 2. The universal motor speed can be controlled by: (a) Centrifugal mechanism only (b) Resistance method only (c) Any one of the given three methods (d) Tapped
1. The normal 3-phase slip-ring induction motor, the developed starting torque will (a) Increase with the increase in the value of the rotor resistance. (b) Decrease with the increase in the value of rotor resistance. (c) Not depend upon the value of the rotor resistance. (d) Increase with increase in the value of the rotor
1. A 3ɸ synchronous motors has been provided with damper winding. It can be started as a (a) Single phase synchronous motor. (b) 3ɸ squirrel cage induction motor. (c) 1ɸ induction motor. (d) 3ɸ alternator. [UPSSSC 2015] 2 Consider the following statements about a three-phase synchronous generator synchronized to an infinite bus when its mechanical
1. A DC cumulatively compounded motor delivers rated load torque at rated speed. If the series field is short-circuited, then the armature current and speed will (a) both decrease. (b) both increase. (c) increase and decrease respectively. (d) decrease and increase respectively. 2. A dc cumulatively compounded generator was operating satisfactorily and supplying power to
1. In a 3-phase power transformer, 5-limbed construction is adopted to (a) suppress the 5th and 7th harmonics. (b) suppress the 3rd and its multiple harmonics. (c) suppress all the orders of harmonics. (d) increase the capacity of the transformer. 2. Consider the following statements: The use of Delta-connected tertiary windings in star-star connected power
1. Corona is (a) partial breakdown of air. (b) complete breakdown of air. (c) sparking between lines. 2. Which of the following statements is true regarding corona ? (a) Corona takes place at a voltage lower than breakdown voltage. (b) Corona takes place at a voltage higher than breakdown voltage. (c) Corona is a current
1. Which one of the following is correct ? (a) The effect of field current on main flux of a synchronous machine is called armature reaction (b) The effect of air gap flux on armature current of a synchronous machine is called armature reaction (c) The effect of armature current on main flux of a
1. The voltage wave v = Vm sin (wt – 15°) volts is applied across an AC circuit. If the current leads the voltage by 10° and the maximum value of currents is Im, then the equation of current is (a) i = Im sin (wt + 5°) amps (b) i = Im sin (wt
1. If in an R-L-C series circuit the current lags the applied voltage by 60° then (a) XL – XC = R/√3 (b) XL – XC = √3R (c) XL = XC = R (d) XL – XC = R 2. A lossy capacitor with loss angle of 0.01 radian, draws a current of 0.5