Answer / k.l.subrahmanyam

Actually electrical machines can with stand fluctuations in
frequency in cirten limits according to the manufacturer
design.if decided to give more than the limits the rpm of
the machines increased normally.according to machine rating
the stator core and insulation of the winding designed due
to this high frequency the eddy currents induced in the
stator core more than the rating.due to this currents
abnormal heat (i2r)generated due to this the insulation of
the winding damaged and winding will be shorted.

Answer / aamod tripathi

Frequency has a role when the load is either inductive or
capacitive. The inductive reactance or the impedance
offered by inductor increases with increase in frequency
and In case of capacitive reactance the impedance offered
by capacitor decreases with frequency increase.

If the frequency applied to the instrument is more than the
specified frequency the losses increase and can give
devastating results in inductive loads.

for resistive loads frequency has no meaning.

for measuring instruments. the construction of the
measuring instrument needs to be checked if PMMC or MI or
induction type.... it will increase the oscillations or
will give incorrect reading. It shall be noted this is why
each and every electrical instrument/ Machine/ Grid has a
frequency range.

Answer / sankar

if its a motor its ok.. what about other instruments.
... if its an iron box or electric heater then what will happen..

PLZ sent the previous year question paper for GET in NHPC on my EMail id ppshanker@gmail.com

0 Answers   NHPC,

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