Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!usc!apple!xanadu!michael From: michael@xanadu.com (Michael McClary) Newsgroups: sci.electronics Subject: Re: Watt Hour Meters Message-ID: <1990Feb2.143012.11352@xanadu.com> Date: 2 Feb 90 14:30:12 GMT References: <25675@cup.portal.com> <1262@island.uu.net> <1105@rsiatl.UUCP> <1452@umigw.MIAMI.EDU> Reply-To: michael@xanadu.UUCP (Michael McClary) Distribution: usa Organization: Xanadu Operating Company, Palo Alto, CA Lines: 20 In article <1452@umigw.MIAMI.EDU> wb8foz@mthvax.cs.miami.edu (David Lesher) writes: > >One question I never asked a utility when I should have... > >Virtually everything causes inductive power factor problems. You >correct for it (typically) with capacitors (some old-timers may call'em >condensers, but I think those belong to steam engines and HVAC units :-}). > >What does the utility think if you offer to correct other people's >leading PF by having too many farads? They don't like that, either. Their resistive losses go with I-squared-times-R, and generators and transformers are limited by heat, and thus handle a maximum current, not a maximum power. So utilities want as much of the current to be in-phase as can be managed. (By the way, idling synchronous motors can also "generate" VARs {be capacitive}. Factories would just switch to all synchronous motors if the utility paid for VAR generation.)