Hi Duncan, Hehe it's not all about winning (well, unless you're Charlie Sheen) but anyway it's interesting you say it's about kWh and not kVA since you're one of those people that link I mentioned is referencing-since you have that new digital 'smart' meter, the power company is now going to probably try and charge you for VA use in the future to encourage energy efficiency-so if you have and old AC unit that only has a PF of .6, that will encourage you to get smart and upgrade to a newer one with a higher PF...
Only speculation on my part, but that is what I would expect since the power company has to generate the VA but only gets to charge you for the watts...here's that link again: http://www.generatorguide.net/watt-acpower.html Oh and my point about the VA rating of a device really applies to UPS sizing at this point! To use your example, it's exactly why a 1500VA UPS can only supply 875 watts of real power, based on how UPS manufacturers rated their UPS for PC computer loads... Do me a favor Duncan, read this link and tell me if it makes sense or not: http://www.power-solutions.com/watts-va.php I think it should and then you (just like me) will get the difference in VA vs watt ratings for most UPS in the consumer-grade category! HTH! BINO P.S. Really, the takeaway from that last link is that UPS manufacturers have been overestimating/lying about their VA ratings for UPS for PC use to make them sound bigger, when it reality they can only handle much less, i.e. their watt rating! Whereas with bigger UPS (but I don't know what constitutes "big" in this case), their VA rating=watt rating... > Date: Tue, 2 Aug 2011 12:28:09 -0400 > From: [email protected] > To: [email protected] > Subject: Re: [H] PFC (power factor corrected) PS for PCs? > > Bino, > OK. You win! Yes the AC voltage you measure at the wall plug is 0.707 > (rms) of the peak AC sinusoidal wave-form (169.731V) when viewed via an > o-scope. My comment was with regards to your concern about KWh and KVA > values. In your apartment you spend your dollars buying AC power > measured in Watts not KVA. > > Yes, have read about these new digital 'smart' residential watt-meters. > I have one on my home now. And I fully expect that in the future (as my > AC Service provider completes it's 'Smart Grid' technology) I may see my > bill change based on 'time of day' power usage during peak demand > (system wide) situations. > > Yes, it is confusing in the UPS calculation game. All of my UPS's are > rated at 1500KVA. Yet, they also will only supply a maximum output of > 875 watts continuous. > > I do not follow your points about 'VA' rating of a device. If it plugs > into your wall plug it is spec'd in watts. > My understanding about Power Factor and/or Power Factor Correction > technology is some form of quantifying electrical efficiency. IMHO. I > leave area to the those that understand. I do not. Yet I do agree that > our modern PSU's are very much more efficient AC to DC converters. > Sorry to interject skepticism into your search for truth. > Best, > Duncan >
