Question { SSC, 20560 }

Why birds seating in HT line does not get shock?
If person hangs in HT line (single hand or both hands) does
he get shock?

Answer

IF A MAN HANGS ON HT LINES HE DOESNT GET ANY SHOCK BECAUSE
FOR THE CURRENT TO FLOW THERE SHOULD BE A POTENTIAL
DIFFERENCE AND IF THE MAN HANGS WITH TWO HANDS THE
DIFFERENCE BETWEEEN THE POTENTIALS OF TWO POINTS HE HANGS
FROM IS NOT PREDOMINANT AND IS NOT HIGH ENOUGH TO GIVE
SHOCK.

Question { Heidelberge Cement, 7780 }

what is the avr

Answer

AVR is Automatic Voltage Regulator and is essentially an
autotransformer and has two windings in it namely exciting
winding and series winding.
Exciting windimg is connected in parallel with the circuit
and the series winding is in series with the circuit.
series winding has tappings on it variation of which leads
to variation in the voltage at the secondary side.
It can boost aswellas buck the voltage depending on the
connection of the reversing switch that connects the series
winding to the ckt.

Question { ISRO, 7347 }

How to calculate % Impedence?

Answer

IT IS THE RATIO OF THE VOLTAGE DROP IN AN IMPEDANCE WHEN
FULL LOAD CURRENT IS FLOWING IN IT TO THE BASE VOLTAGE OF
THE SYSTEM.

Question { 3402 }

is it possible to step down voltage of single phase from a
three phase sysem? explain

Answer

Yes, we can use autotransformer connection or tappings on
one phase to get the reduced voltage in one particular
phase while all the other phases give the same magnitude of
voltage as before to the load. As the tapping is varied we
can get the variable voltage.