This doesn't mesh up with what I've learned about power factor -- the impression that I got was a perfect power factor was 1 (one) (current in phase with voltage, equipment using everything the the power company charges you for to do useful work). Anything other than PF=1 meant that the equipment was using the power less efficiently, and therefore you were paying more in KWH than the work actually performed. That description excludes the possibly that the equipment could use more power than the power company records as being delivered (heck, conservation of energy says that in any case). any load reactance (inductive or capacitive) and the very low PF numbers stated sound more like what I get off my linear power supplies with big capacitance and no power factor correction. In any case, anything other than PF=1 should mean that you are paying for more power than you are actually using.
Tell me where I goofed this up ?? Bob M. wrote: > > Thank you Eric. This was the explanation I was looking for. The UPS is > saving me money when drawing 181 Volt-Amps, yet the electric meter is > only recording and charging me for 31 Watts. I wonder if APC did this > on purpose. I don't know how much current is actually being fed to the > batteries; they've been in there for a couple of months and should be > fully charged by now, so it should just be trickling them (eight 12V > 7A SLA cells in series/parallel for 48V). > > Bob M. > ====== > --- On Tue, 9/16/08, Eric Lemmon <[EMAIL PROTECTED] > <mailto:wb6fly%40verizon.net>> wrote: > > > From: Eric Lemmon <[EMAIL PROTECTED] <mailto:wb6fly%40verizon.net>> > > Subject: RE: [Repeater-Builder] Volt-Amp (Re: APC UPS Charging Power) > > To: [email protected] > <mailto:Repeater-Builder%40yahoogroups.com> > > Date: Tuesday, September 16, 2008, 9:21 PM > > Albert, > > > > You are forgiven, because you pose an important question! > > > > The spinning aluminum disk in the kilowatthour meter found > > on most > > residential service-entrance panels measures true power in > > kilowatts versus > > time, which equals energy. Thus, your electric utility > > charges you for the > > true power you use, not for volts times amperes- known as > > reactive power. > > Although the utility must provide the capability to supply > > all of the > > amperes you need, some of those amperes are "given > > back" to the utility due > > to a lower than unity power factor. That is why many > > utility companies > > charge a "kVAR Penalty" to certain industrial > > power users whose volt-ampere > > demands far exceed their watt demands, meaning that the > > power factor is low. > > Industrial power users strive to keep their power factors > > at 0.95 or above, > > to avoid some really painful penalties! The power factor, > > or PF, is simply > > watts divided by volts time amperes. > > > > The issue of power factor is why large Diesel generator > > sets have ratings > > such as 1000 kW/1250 kVAR. In simple terms, any AC > > generator requires > > torque (engine horsepower) to meet true power demands, and > > excitation (field > > flux intensity) to meet reactive power demands. When the > > generator load is > > reactive, that is, it has a power factor less than unity, > > the generator must > > not only have the horsepower to supply the energy in watts, > > but it must have > > excess capacity to handle the additional current required > > by motors and > > other low-power-factor loads. In a nutshell, that is why a > > 1000 watt > > generator may be unable to keep running a refrigerator that > > uses only 900 > > watts; the fridge may require 1200 VA to operate because it > > has a low power > > factor, and the small generator has no ability to handle > > such loads. > > Because of its relatively small amount of spinning mass, > > such a small > > generator probably could not even handle the > > refrigerator's starting > > current- which is about 5 to 6 times its running current. > > > > 73, Eric Lemmon WB6FLY > > > > > > > > -----Original Message----- > > From: [email protected] > <mailto:Repeater-Builder%40yahoogroups.com> > > [mailto:[email protected] > <mailto:Repeater-Builder%40yahoogroups.com>] On Behalf Of > > Albert > > Sent: Tuesday, September 16, 2008 2:13 PM > > To: [email protected] > <mailto:Repeater-Builder%40yahoogroups.com> > > Subject: [Repeater-Builder] Volt-Amp (Re: APC UPS Charging > > Power) > > > > Hopefully, you will forgive me for hijacking the post, but > > this brings up a > > question I have had for a long time. What on earth is a > > "volt-amp"? > > My logic would state that is is the same as a watt, which > > is volts x amps, > > as you probably well know. So what on earth is it? > > > > Confused..... > > > > Albert > >
