IIRC... VA for AC is peak volts times amps, not RMS volts. The whole point of dealing with RMS being that it makes AC and DC equiv for purposes of V * A = W.
Converting VA to W is same as converting peak V to RMS V. Though I am a little surprised about residential power being measured/billed in VA not KW/h in North America. Pretty sure the US is in North America, even Alaska in slightly more North America. Never seen a VA/h meter in the US. Was guessing it was a CA thing, even though I had never run across any mention of VA billing in CA, but am looking at Manitoba Hydro, NB power and SaskPower billing rates right now in KW/h. Ed, can you chime in here, where is power billed by VA (outside of some commercial/industrial and private generation agreements)? VA is used all over the place in electrical systems calculations and equipment specs but have never seen billing on it. On 8/19/12 11:19 AM, Tom Knox wrote: > > Hi Ed; > I may not have had enough coffee yet, but if Volt X Amps = Watts why would > there be a difference? > Best Wishes; > Thomas Knox > > > >> Date: Sun, 19 Aug 2012 12:35:51 -0600 >> From: ed_pal...@sasktel.net >> To: time-nuts@febo.com >> Subject: Re: [time-nuts] Modern motherboard with RS232 port >> >> It's important to remember that on a computer, the wattage shown has no >> relationship to the wattage pulled from the socket. The numbers shown >> are maximum values. You have to measure the power draw and you have to >> measure it in volt-amps, not watts because that's how residential power >> is measured (at least in North America). Buy an energy meter that shows >> volt-amps. They're relatively cheap - typically less than $50. >> >> Ed >> >> On 8/19/2012 11:06 AM, Chris Albertson wrote: >>> This sounds like a newer version of the board I use. The thing to check >>> is if the CPU heat sink has a fan or not. Having no fan indicates that the >>> CPU is not using much power. It also removes a common failure point. >>> >>> To reduce power even more. On an NTP server you can unplug the keyboard, >>> mouse and monitor and if you have other servers on the LAN configure one as >>> a "boot server" and have it run TFTP then your NTP server does not need a >>> disk drive. It can run off a "RAM disk". This makes it very fast, even >>> faster than a SSD and it saves some cash. Makes backup easy too as there >>> is nothing to backup if there is no local storage. If you don't have a >>> TFTP server use a small notebook size disk drive. Even a 80GB drive is >>> overkill. You can also boot from a USB thumb drive and run a RAM disk. >>> >>> It is worth it to look at your electric bill to find how much you pay for >>> power. Here I'm at $0.21 per KWH. A full size PC server can use 250W or >>> more. There are 8760 hours in a year so you get $460 per year to run that >>> 250W PC. The little Atom will pay for itself in just a few months. The >>> first time I did that calculation, my "power hogs" where given away. >>> >>> >>> >>> >>> On Sun, Aug 19, 2012 at 7:42 AM, Stan, W1LE <stanw...@verizon.net> wrote: >>> >>>> Hello The Net, >>>> >>>> For your consideration: >>>> >>>> The INTEL model DN2800mt ITX mother board uses a ATOM CPU and >>>> draws about 11 watts of AC power when configured as: >>>> (I have not measured DC power yet.) >>>> >>>> 30 GB OCZ Nocti mSATA solid state drive, >>>> WIN7 pro, 64 bit, USB keyboard and mouse >>>> APEX MI-0008 case. >>>> >>>> Also has: >>>> parallel port available on mother board, you extend to a connector >>>> RS232 serial port available on mother board, you extend to a connector >>>> a single DC power supply from 11 to 19 V DC. >>>> 1 each PCIe expansion port, I will use with a premium 4 channel sound card >>>> SATA ports available for HDD/SDD, >>>> USB ports are available, >>>> Motherboard sound, and Gigalan. >>>> >>>> I have not played with NTP, (yet), but it sounds like a decent time nut >>>> technical challenge. >>>> >>>> My application is for a remote site with only 13V DC power available from >>>> PV/batteries. >>>> Then use fiber ethernet to get off site. >>>> >>>> The INTEL website would have further details. >>>> >>>> Stan, W1LE Cape Cod FN41sr >>>> >>>> >>>> >>>> >>>> ZZZZz >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
