The field winding of an alternator
requires
In synchronous motor, minimum armature
current occurs at
The motor used in ceiling fans is
The slip of an induction motor under
full load condition is about
If copper loss of transformer at 7/8thof full load is 4900
W, then full load copper loss would be
The purpose of the conservator in a transformer
is
In case of a power transformer, the no
load current in terms of rated current is
Interpoles are meant for
The no load speed of DC series motor
is
For battery charging, which of the
following DC generators is used?
If supply frequency increases, the
skin depth is
The most common type of unsymmetrical
faults in three-phase system is
The value of demand factor is
The power factor of industrial loads
is generally
Megger is an instrument used to
measure
A dynamometer type wattmeter responds to the
Which of the following meters is an
integrating type instrument?
The scale of Moving Iron (MI) instrument is
HRC
fuse provides best protection against
A
relay performs the function of
Which
of the following AC bridge is preferred for the measurement of inductance
having high Q-factor?
Which
of the following instruments is an integrating type instrument?
A
dynamometer type wattmeter can be used on
If
the fault current is 2000 amp, the relay setting at 50% and CT ratio is 400/5,
then the plug setting multiplier will be
The
power factor of a spot welding machine is expected to be around
Which
of the following processes essentially needs direct current?
A
lighting arrestor is usually located nearer to
A
load power factor of 0.95 lagging implies reactive power demand of
Mho relay is normally used for the protection of
Which
of the following is not a standard transmission voltage in India?
Which motor has widest variety of methods for speed control?
For
traction work, which motor is preferred?
Induction
generator works between the slip of
A 100V/10V, 50VA transformer is converted to 100V/110V auto transformer, the rating of the autotransformer will be
The
unit of luminous flux is ________ .
Which
motor has the poorest speed control?
A
synchronous phase modifier as compared to a synchronous motor used for
mechanical loadhave :
Which
DC motor is generally preferred for cranes and hoists?
Two
DC series motors are connected in series to produce a torque T. Now if the
motors are connected in parallel, the torque produced will be
A
transformer has maximum efficiency at full load. When iron losses are 800
watts, copper losses at half load will be
A
universal motor can be operated on 220 V DC as well as 220 V single phase AC.
Which of the following will be same in the two cases?
How
many different speeds can be obtained in cascade control of two induction
motors?
Which
of the following is preferred rpm for 4 pole induction motor?
Torque
angle of synchronous motor is
The
percentage slip in case of synchronous motor is
Two
alternators A and B are sharing the inductive load equally. What will happen
when the excitation of A is increased?
Zero
power factor method for an alternator is generally used to determine
The voltage V and current i of a device are
The power P indicated by wattmeter
will be
The
effective value of voltage given by V = 100+ 25 sin 3
+ 10 sin 5 will be
For the circuit shown below, voltage V1 will be
