ELECTRICIAN

ELECTRICIAN

The variation of power factor with respect to the field
current is called ...............
(a) V curve
(b) Inverted curve
(c) Hysteresis curve
(d) Circle diagram
Answer: (b) Inverted curve

When asynchronous motor is running at
synchronous speed, the damper winding
produces.................
(a) Damping torque
(b) Eddy current torque
(c) Torque aiding the developed torque
(d) No torque
Answer: (d) No torque
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A motor which can conveniently be operated
at lagging as well as leading power factor is
the...................
(a) Squirrel cage induction motor
(b) Wound rotor induction motor
(c) Synchronous motor
(d) DC shunt motor
Answer: (c) Synchronous motor

A synchronous motor is operating on no load
at unity power factor. If the field current is
increased, power factor will become............
(a) Leading and current will decrease
(b) Leading and current will increase
(c) Lagging and current will decrease
(d) Lagging and current will increase
Answer: (a) Leading and current will decrease

The frequency of ripple in the output voltage of a
three phase Half controlled bridge rectifier
depends on the................
(a) Firing angle
(b) Load inductance
(c) Load resistance
(d) Supply frequency
Answer: (d) Supply frequency

A PWM switching scheme is used in a three phase inverter to........
(a) Reduce total harmonic distortion with modest filtering
(b) Reduce low order harmonics and increase high order harmonics
(c) Minimize the load on DC side
(d) Increase the life of the batteries
Answer: (b) Reduce low order harmonics and increase
                 high order harmonics

Which of the following is a Shell type of transformer lamination?
(a) T & I type
(b) E & T type
(c) U & I type
(d) T & U type
Answer: (d) T & U type
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For a given number of poles(2) and armature conductors,
a hp winding will carry.............a wave winding.
(a) More current than
(b) Same current as
(c) Less current than
(d) Half the current than
Answer:  (a) More current than

An Eight pole duplex lap winding will have ......... parallel paths.
(a)  8
(b) 12
(c)  32
(d)  16
Answer:  (d)  16

In a simplex wave winding the number of
parallel paths is equal to
(a) Number of poles in the machine
(b) Two
(c) Number of pair poles
(d) One
Answer: (b) Two