Question { Wipro, 249915 }

What is min and max voltage between earth and neutral/phase
if it perfect earthing?

Answer

This will depend on the earthing arrangment
plz check IEC 60364-5-54 Electrical installations of
buildings - Selection and erection of electrical equipment -
Earthing arrangements

Question { 14432 }

for 12KW motor which cable size has to select for ex.10
meter.

Answer

The cable size will depend on the you rated voltage and
cable route you can reffered to
IEC 60364-5-52 Electrical installations of buildings -
Selection and erection of electrical equipment - Wiring
systems
or from electrical installation guid from schneider site.

Question { 8949 }

The neutral to earth connection in my industry is showing a zero reading
(shorted). I have a machine which has to be installed where neutral to earth is
not shorted and shows a leak voltage <3 Volts. Please suggest me how it is
possible.

Answer

Hi Ravi
Of course if you have your power supply neutral earthed
from supply side (transformer or generator neutral) you
will get zero potential at between the neutral and earth at
any point of the distribution circuit ; you should get more
information about the type of your earthing system (IT, TT,
TN-S or TNC)
You can find more details at Schneider site or ABB sites
or directly from IEC 60364-5-54 Electrical installations of
buildings - Selection and erection of electrical equipment -
Earthing arrangements

Question { 24092 }

What is the reactive power and how to control the reactive
power in power plant

Answer

We could define the reactive power if we how it generates
as follow.
All inductive (i.e. electromagnetic) machines and devices
that operate on AC systems convert electrical energy from
the power system generators into mechanical work and heat.
This energy is measured by kWh meters, and is referred to
as “active” or “wattful” energy. In order to perform this
conversion, magnetic fields have to be established in the
machines, and these fields are associated with another form
of energy to be supplied from the power system, known
as “reactive” or “wattless” energy.