20 practice sets · Page 1 of 1
In a core type transformer
any of the LV or HV can be placed nearer to the core limb
HV and LV windings are placed in different core limbs
HV winding is placed nearer to the core limb
LV winding is placed nearer to the core limb
If the supply frequency of a transformer increases then output voltage of the transformer will
remain same
increases very rapidly
decrease
increase proportionately
What will be the eddy current loss if the supply frequency of a transformer becomes double?
Doubled
Remains same
Eight times
Four times
Which of the following losses varies with load in transformer?
Eddy current loss
All losses in transformer vary with load
Copper loss
Hysteresis loss
Which of the following losses remain constant during normal operation of transformer?
Core loss
All losses in transformer vary with load
Copper loss
Stray loss
No load losses in a transformer can be minimized by using steel of
only high silicon content
only very thin lamination
low silicon content and very thin lamination
high silicon content and very thin lamination
Iron loss in transformer can be determined by
open circuit test
both short circuit and open circuit tests
none of the above
short circuit test
In a transformer the coils of primary and secondary are placed concentrically to achieve
reduced copper losses in the winding
reduced insulation cost of the windings
reduced voltage per turn in the winding
reduced leakage flux between primary and secondary winding
The input power under no load condition of transformer consists of
core losses and very small amount of copper loss in primary
copper loss in transformers
significant copper loss along with negligible core losses
core losses in transformer
In an ideal transformers primary and secondary induced emfs are
mutually induced emfs
self and mutually induced emfs respectively
mutually and self induced emfs respectively
self induced emfs
In an ideal transformer the magnetizing current lags behind applied primary voltage by an angle
75 degree
-90 degree
45 degree
90 degree
An ideal transformer is one which has
no leakage reactance
no losses
all of above
no winding resistance
The working principle of transformer depends upon
Lenz Law
Flemings left hand rule
Faradays law of electromagnetic induction
Ohms Law
The core of transformer must have
high resistance
high reluctance
low resistance
low reluctance
Secondary current of a step down transformer is
higher than primary current
equal to primary current
double than primary current
lower than primary current
Which parameter does not change during transformation action in transformer?
Frequency
Current
None of these
Voltage
The primary and secondary winding of transformer are linked each other by
mutual induction
not linked at all
self induction
conduction
As compared the transformer with AC machines it is more efficient because
it does not have copper losses
core losses negligible
none of above
it does not have mechanical losses
In transformer, humming sound occurs due to
load
magnetostriction
none of above
oil
When AC supply is given to the transformer, the flux will depend on
voltage
frequency
both voltage and frequency
current
