On Sat, 12 Nov 2005 03:49:19 GMT, "Edwin Pawlowski"
wrote:


"Beachcomber" wrote in message

If you are paying a lot for a
significantly low power factor (well below 0.8), you can take steps to
correct it at your own expense. Mostly these involve adding shunt
capacitors to the line possible with a timer control.

This was done a few years ago. I'll have to dig out some bills ot see how
well it worked. There were three or four capacitors at different locations
in the plant.. This is allegedly better than one big one at the 800A main
panel.


You have to match the applied reactive power correction to the
different times of day when your motor loads are creating a low power
factor. Otherwise, an overcorrection (too much capacitive reactance)
is just as bad, if not worse and may make your line voltage levels
fluctuate all over the place.

It matters not if it is done at different locations or the main panel
(assuming the main panel feeds the entire plant). A good main panel
installation will have matched banks of capacitors that can be added
in stages to correct the power factor. This can be automatic,
timer-driven, or manually controlled.

It all depends on the load and mostly the motor load for that part.
Is your plant idle at night, weekends, holidays? Are all motors
running continously or do you have a lot of start-stop operations?
You may have a base load (say of pumps and air blowers) that are on 24
hours a day, hence there might be the need for a certain base value of
power factor correction.

Beachcomber