MULTIPLE CHOICE QUESTIONS
Q.1 A
3 stack stepper
motor with 12
numbers of rotor
teeth has a
step angle of ____________.
(A)
12°
(B) 8°
(C)
24°
(D) 10°
Q.2 In case of a universal motor, torque
pulsation is minimized by _________.
(A) load
inertia
(B) rotor inertia
(C) both rotor and load inertia
(D)
none of the above
Q.3 The
speed-torque characteristics of a DC
series motor are
approximately similar to
those of the
_________motor.
(A) universal
(B) synchronous
(C)
DC shunt
(D) two-phase
Q. 4 The
rotor frequency for a 3
phase 1000 RPM
6 pole induction motor
with a slip
of
0.04
is________Hz
(A) 8
(B) 4
(C) 6
(D)
2
Q.5 The
torque-speed characteristics of an a.c.
operated universal motor
has a______characteristic
and it______ be started under no-load condition.
(A) inverse, can
(B) nearly inverse, can
(C) inverse, cannot
(D) nearly inverse, cannot
Q.6 In order to reduce the harmful effects of
harmonics on the A.C. side of a high voltage D.C. transmission system ______are
provided.
(A)
synchronous condensers
(B) shunt capacitors
(C) shunt filters
(D)
static compensators
Q.7 An
a.c. tachometer is
just a ________with
one phase excited
from the carrier frequency.
(A) two-phase A.C. servomotor
(B) two-phase induction motor
(C) A.C. operated universal motor
(D) hybrid stepper motor.
Q.8 The torque, in a _____________is proportional
to the square of the armature current
(A) DC shunt motor
(B) stepper motor
(C) 2-phase servomotor
(D) DC series motor
Q.9 The
synchronous speed for a 3
phase 6-pole induction
motor is 1200
rpm. If the number of poles is now reduced to 4 with
the frequency remaining constant, the rotor speed with a slip of 5% will be
_________.
(A) 1690 rpm
(B) 1750 rpm
(C) 1500 rpm
(D) 1710 rpm
Q.10 The eddy current loss in an a-c electric
motor is 100 watts at 50 Hz. Its loss at 100 Hz will be
(A) 25 watts
(B) 59 watts
(C) 100 watts
(D) 400 watts
