On Tue, Oct 18, 2011 at 11:37 AM, Stefan Jafs <stefan.j...@gmail.com> wrote: > I'm, trying to figure out how much it cost to run some of our Medical Gas > Alarm, current draw is 290 mA at 120 Volts, any ideas? > This are my guess after some searches: > > .290 * 120 = 34.8 VA * 60% (PF) = 20.9 Watts I think that's correct ...
Looks good to me, assuming your figure for the power factor is correct. >... but how do I get to kWh? Run it for an hour. ;-) 20.9 watts is 0.0021 kilowatts. Run it for an hour, and it's 0.0021 killowatt*hours. Run it for half an hour, and it's 0.0011 killowatt*hours. Run it for two hours, and it's 0.0042 killowatt*hours. Run it for about 476 hours, and it's 1 killowatt-hour. (1 / 0.0021 = 476.190) Water makes a good analogy for electricity: voltage = pressure (how hard is it pushing?) amps = pipe diameter (how much can the wire/pipe carry?) watts = gallons/hour (how much does it use to run?) killowatt*hours = gallons (total amount of water/power) High pressure (voltage) in a small pipe (wire, amps) still yields a high gallons/hour (watts). How long you run the hose (equipment), times the rate of flow (watts) determines the amount of water (power, killowatt*hours) you use. -- Ben ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~ --- To manage subscriptions click here: http://lyris.sunbelt-software.com/read/my_forums/ or send an email to listmana...@lyris.sunbeltsoftware.com with the body: unsubscribe ntsysadmin
