Answer / surya

the 4kvar capacitor improve the pf but you must keep in
mind that installed the capacitor permanentely only at load
time.switched off the capacitor on unload time since i
think at unload time the 4kvar capacitor become a self-load
& increase your electricity bill.

Answer / hareesh

The purpose of capcitor is to improve pf according to
load.the worst pf at no load.at no load capacitor draws
more current than full load and improve pf.power consuming
by the capacitor is reactive power which will not count by
EM.

required capa.(kvar)=p*(tan(inv cos(pf1))- tan(inv cos(pf2))

p= total power in kw
pf1=actual pf
pf2=required pf

Answer / raj

You have to calculate and put partially some capacitor
permanentely ON which will neutralized or improve the PF
when Transformer charged with NO load condition and other
capacitor should be connect through contactor so that as
welding machine will on capacitor will on ( interlocking
between both ).If PF increase or reached to Leading side
means it will work as a load and you have to pay extra
amount in your bill.
PF Calculation Formula

required capa.(kvar)=p*(tan(inv cos(pf1))- tan(inv cos(pf2))

p= total power in kw
pf1=actual pf
pf2=required pf

Answer / ranadev datta

The transformer at no load has a pf depending on relative
values of its no-load kW loss and the apparent no-load kVA.
A capacitor permanently connected to the LV side should be
of a kVAR value to just correct the inductive kVAR at no-
load and no more.

Separate sets of capacitors should be judiciously applied
to correct the pf on load. The best thing to do is to
switch the pf-improvement capacitors on and off along with
the switching of the individual offending loads (e.g., by
connecting the capacitors of appropriate ratings to the
motor terminals) thereby bringing about
inherently 'automatic' control of capacitor switching.

Answer / rameez ajmeri

when the capacitor is switched on at load it will improve
the power factor, but you have to take care that the
capacitor is switched on when there is no load on the
transformer...we have to take care about that...

Answer / arsenal

capacitors connected on the lv side at no load will take
charging current...........as a result it will act as a
self load...........

Answer / k.prakashchandra

Most of the Elec boards consider only the average pf which
is =Kwh/Kvah for the billing month.Fix individual capacitors
on load side or APFC

Answer / m s venkateswara rao

It is not possible to maintain constant power factor at variable load. A little bit expensive but you have to go for procure auto pf panel, installed and connected immediately after EB meter.In APF panel controller you should set the pf range so that at different loads APF panel will automatically will switch on different rating of capacitors to maintain set pf.

Answer / amrinder

how capacitors connected in parallel to each phase i.e
R,Y,B giving a resultant of 4 KVAR become a self load at
noload time of transformer and increase the electricity
bill.......... please explain in detail......waiting

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