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
1. The value of voltage across the diode in figure given below is (a) Zero volt (b) 4 V (c) 8 V (d) Depends upon the value of R 2. The temperature co-efficient of an intrinsic semiconductor is (a) Zero (b) Positive (c) Negative (d) Like that of metals 3. A 4-pole, 1200 rpm DC
1. The value of current I flowing in the 1 ohm resistor in the circuit shown in the figure below will be (a) 10A (b) 6A (c) 5A (d) zero 2. In the figure shown below, if we connect a source of 2V, with internal resistance of 1 ohm at AA’ with positive terminal at
1. The Forth Military World Games were held in October, 2007 in India at (a) Hydrabad (b) Chennai (c) Ahmedaba (d) Lucknow 2. Who of the following received the Sanskriti Award for 2007 in the field of literature? (a) Jyotshna Kalita (b) K.A. Shaji (c) K.P. Reji (d) Bijayini Satpathy 3. The legislative Council in