A transformer transforms
voltage
current
power
frequency
power
A transformer cannot raise or lower the voltage of a D.C. supply because
Faraday’s laws of electromagnetic induction are not valid since the rate of change of flux is zero
none of the above
a D.C. circuit has more losses
there is no need to change the D.C. voltage
Faraday’s laws of electromagnetic induction are not valid since the rate of change of flux is zero
Greater the secondary leakage flux
less will be the secondary induced e.m.f.
less will be the primary terminal voltage
less will be the primary induced e.m.f.
none of the above
less will be the secondary induced e.m.f.
The purpose of providing iron core in a step-up transformer is
to provide all above features
to decrease the magnitude of mag-netizing current
to provide coupling between primary and secondary
to increase the magnitude of mutual flux
to decrease the magnitude of mag-netizing current
The power transformer is a constant
main flux device
voltage device
current device
power device
main flux device
Two transformers operating in parallel will share the load depending upon their
ratings
efficiencies
leakage reactance
per unit impedance
per unit impedance
Which of the following does not change in a transformer ?
Current
Voltage
Frequency
All of the above
Frequency
In a transformer the energy is conveyed from primary to secondary
by the flux
none of the above
through air
through cooling coil
by the flux
A transformer core is laminated to
reduce eddy current losses
reduce copper losses
reduce hysteresis loss
reduce all above losses
reduce eddy current losses
The degree of mechanical vibrations produced by the laminations of a transformer depends on
size of laminations
all of the above
tightness of clamping
gauge of laminations
all of the above
पोस्ट अच्छी लगी हो तो प्लीज नीचे दिए गए लिंक पर क्लिक कर शेयर जरुर करें
0 Comments