Answer Posted / gans

kVA is the unit for apparent power. Apparent power consists
of active and reactive power. Active power is the share of
the apparent power which transmits energy from the source
(generator) to the user. Reactive power is the share of the
apparent power which represents a useless oscillation of
energy from the source to the user and back again. It occurs
when on account of some »inertia« in the system there is a
phase shift between voltage and current. This means that the
current does not change polarity synchronous with the
voltage. But the heat generated in a winding as well as the
eddy current losses generated in a transformer core depend
on the current only, regardless of whether it aligns with
the voltage or not. Therefore the heat is always
proportional to the square of the current amplitude,
irrespective of the phase angle (the shift between voltage
and current). So a transformer has to be rated (and
selected) by apparent power.

why the earth is taken minimum in supplying? wather it the proportional factor to getting work any equipment or a power plant?

1828

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Whether IP65 enclosure box blocks ventilation if driver for LED have to enclosed inside IP65 box

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Is it possible to implement Restricted Earth Fault protection for a transformer without neutral CT?

4241

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1857

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what will be the min and max voltage flow from neutral to earth?

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Please brief working principle & construction of permanent magnet AC Servo motor

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Thermal withstand capability under full short circuit conditions, in terms of number of times of occurrence of short circuit and corresponding anticipated percentage reduction in transformer life.

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5188

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Give idea about General Engineering. From which book i can study this topic. Pl. reply me via email. My email is ravi@bhelhwr.co.in, also give the name of book/website, from where i can prepare it.

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explain which quantities change in the starting and the and the running condition in induction motor

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