Volts times Amps isn't necessarily watts in AC circuits. It has to do with the phase relationship of the voltage and current. If they are exactly in phase then volts times amps is watts. But if they are out of phase the watts are less than volts times amps. How much less depends on how far the current and voltage are out of phase. Airconditioners are nearly always inductive loads which makes the current and voltage out of phase. The wire size and circuit breaker have to be rated for the volt amps not the watts. The horse power of a motor is related to the watts.
Regards. Max. K 4 O D S. Email: [EMAIL PROTECTED] Transistor site http://www.funwithtransistors.net Vacuum tube site: http://www.funwithtubes.net Music site: http://www.maxsmusicplace.com To subscribe to the fun with tubes group send an email to, [EMAIL PROTECTED] ----- Original Message ----- From: <[EMAIL PROTECTED]> To: <[email protected]> Sent: Monday, July 30, 2007 11:16 PM Subject: [BlindHandyMan] watts vs VA > Hi, > My electrical math is shallow. > But I thought, that volt times amp will give you a number equalling the > amount of watts that one can pull from a circuit. > A standard 117v at 15A is 1750 (1755 to be exact) > I thought this came up while we were discussing how a (rounded off) 120v > device can't give the HP that some units claim. So you guys figured that > it must be momentary, to start, or burst HP, or hype in some of those > claims. > > So wattage vs VA: > In heavy duty power back up for heavy amplifiers one unit quoted > 900w/1500VA for 7.5 mins total. > But shouldn't the wattage and the VA be the same? > If not, wy? > We are going overboard, but have been known to lose up to 3 mins in the > start up needed by the AC units. > It's not our building, the need a new bigger service. > So we are just getting back up o\power supply. > What's the real math, is this right? > > Thanks > > > > To listen to the show archives go to link > http://acbradio.org/handyman.html > or > ftp://ftp.acbradio.org/acbradio-archives/handyman/ > > The Pod Cast address for the Blind Handy Man Show is. > http://www.acbradio.org/news/xml/podcast.php?pgm=saturday > > Visit The Blind Handy Man Files Page To Review Contributions From Various > List Members At The Following address: > http://www.jaws-users.com/handyman/ > > Visit the archives page at the following address > http://www.mail-archive.com/[email protected]/ > > If you would like to join the Blind Computing list, then visit the > following address for more information: > http://jaws-users.com/mailman/listinfo/blind-computing_jaws-users.com > > For a complete list of email commands pertaining to the Blind Handy Man > list just send a blank message to: > [EMAIL PROTECTED] > Yahoo! Groups Links > > > > > > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.5.476 / Virus Database: 269.11.0/929 - Release Date: 7/31/2007 > 5:26 PM >
