Power Factor for AC Pumps

[Jeff000]

Originally Posted by sphelps

I'm fairly confident at this point power factors really have nothing to do with a residential power bill, we're billed in kWh and our meters can't measure power factors, only real power in watts.

Some more talk about power factors and correction devices
http://michaelbluejay.com/electricity/powerfactor.html

If you live in Canada you are billed in kwh for a residential service, by law. Pf has no outcome on your bill.

[mrhasan]

Alright so I talked with my prof and he said you are billed for what you consume and its the amount of current that you are taking OUT from the power outlet, not the amount of power that the device is using. Because there is no way an utility meter can determine how much power each of the device is consuming separately. So in this case, since you motor is pulling out 1.8A through a 115V AC line, you meter is going to read 1.8A * 115V * number of operating hours. It cannot see the PF of the motor and the motor doesn't have any sort of feedback circuits that will tell the meter how much it is "actually" consuming. Meter will only note how much current you are sucking in the house for how long and at what voltage line.

So bottom line, your motor is "consuming" 207W from the grid but is using 82W for operation. Its how much you consume that gets billed on, not how much you actually use. Its like those phantom powers, you don't use it but you get billed for it.

I don't know about the calculation that someone did about less amp consumption but no impact on bill - its not theoretically viable. Less current = less consumption from the grid = less bill. Meter's don't look at the rating on the motors, it looks at how much "power" a.k.a V*I you are pulling in.

[sphelps]

That goes against everything I read online, I just don't buy it. My understanding is still that it's not actually using that much current, that just the apparent power and not the actual. That extra 60% of the current in the circuit can't just disappear. A power factor of 0.4 doesn't mean 40% efficient.