what do you mean by PF correction. A motor is rated at 15
kw,415 volts, 0.7 pf and eff of 0.92. The powerfactor is
improved to 0.98 by adding capacitors at the bus. calculate
the current drawn by motor under full load condition before
and after pf correction

Answer Posted / lakshmi

pf correction means power factor improvement. for higher
factor the cutrrnt is reduced there by decresing the losses
and incresed efficiency occurs.
input power = output power / efficiency
I/p = 15000/0.92
= 16304.34 watts
I = p/ (1.732 * v * cos(phi))
= 16304.34/(1.732 * 415 * .7)
= 32.404 Amps before pf correction

I = 16304.34/(1.732 * 415 * 0.98)
= 23.416 Amps After pf correction

from the above values we said that the factor is improved
from 0.7 to 0.98 the current will be reduced from 32.404 A
to 23.146 A respectively.

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