Tony wrote:
Art Todesco wrote:
On 6/26/2010 1:31 PM, Tony wrote:
I'm trying to figure the cost of running the central AC in my house.
Inside was fairly easy, a 1/2hp fan motor. Outside the numbers on the
plate from the factory are long gone. I found on the fan motor that it
is 1/8hp. Now the compressor.... On it is listed the voltage but not the
amps or watts but it does list the LRA (locked rotor amps) of 105.0 It
is a Copeland CR38K6-PFV-370.

I found this site but even this isn't very useful to me only giving me
the RLA of 19. I read the RLA is "rated load amps" and does not mean
"Running Load Amps". RLA being the most current it should draw under the
harshest conditions.

http://www.nordyne.com/literature/8569%20Compr.pdf
The best would be to compare the electric meter with the unit running
and not running. This way you will have actual watt-hours and you
don't have to think of things like power factor, etc. But, it will
change depending on temperature. And the run time will vary when the
temperatures are cooler than when it is just plain hot outside.

That is very difficult with the newer digital electronic meter I have
and the way it's set up. With it on a current transformer the meter
hardly moves at all. The readings have to be multiplied by 20 for the
actual usage.
Hmmm,
I have an Amprobe DMM with built in true RMS reading. IUt has a clamp.
Just set the switch to lo or hi response and clamp, it reads the current
at the moment.