Power Factor for AC Pumps

[mrhasan]

Originally Posted by Delphinus

And electrons. I'm pretty sure electricity has something to do with electrons.

Ummm...electrons? wat's that? can you post a picture? doesn't sound like reef safe to me

[reefermadness]

Residence are only charged for REAL power, not APPARENT power (power factor).

Real power is measured in watts and apparent power is measured in VA (volt-amps).

You will notice on your bill you are being charged a measurement of watts which is real power.

[wmcinnes]

Can we just make this thread die? I don't wanna debate over this anymore!

[beefORchicken]

if you are worried about PF, capacitors can be used to cancel out the inductive load and bring PF back to ~1, probably more trouble than its worth though...

[sphelps]

It's not a debate anymore, it's already been established and some people in the know have posted and confirmed. We don't pay for apparent power and power factors make virtually no difference when it comes to you power bill with the exception of some minor cable inefficiency losses. If you think otherwise you're wrong so consider yourself educated

[wmcinnes]

ive agreed with you the whole time Steve!

[Baldy]

Originally Posted by StirCrazy

nope this is not how it works
here is a simple explanation of PF I found

"Power factor is the percent of electrical power that does work. Resistive loads, such as lights and heater elements, always have unity (1.0) power factor; all power is used for work. Motors, because they are essentially large inductors, lag current and cause power factor issues. A motor with a .85 power factor uses 85 percent of the power for work. 15 percent is wasted.

For example, a 480VAC, 10HP motor with a 1.0 power factor uses 10.6 amps to run at 10HP. Lowering the power factor to .8 requires the motor to consume 13.2 amps to produce that same 10 HP."

I read up on this years and years ago and can talk about it all day (well maybe not all day) but it is hard to sit and type it out, hence the simple explanation I found. we used to be realy concerned with PF with lights to get the efficiency.


you if you have a pump that is rated at 120 watts but has a power factor of .6 in reality it will use 200 watts to do the work. the extra 80watts are lost through ineficient circuts, heat, ect... so when the power company bills you you are billed for the 200 watts. this is why the hydro companies have rebates for big business to upgrade to high PF equipment, it lowers the demand on the grid.

Steve

Ill chime in once more to clear up this misinformation. in your example, "200w" is actually 200VA. apparent power is measured in volt-amps. in a power triangle it is the hypotenuse. the 120w is correct, and is the horizontal side of the triangle. the one no ones talked about yet is the vertical side which is reactive power and its measured in VARs or volt-amp reactive. The power factor is a ratio between apparent power and true power. you are only charged for the true power used, which is the watts. that is the current that is in phase with the voltage. reactive power leads or lags the voltage, and isnt measured by residential meters. in this example, you will be charged for 120w NOT 200w.

[StirCrazy]

Originally Posted by Baldy

in this example, you will be charged for 120w NOT 200w.

Unless your with bc hydro on a smart meter which can and do measure aparent power. A lot of people are pointing to this as the reason there power bill has increases after smart meter instalation. Other places who have smart meters in the us had the same problem.

Understand the reason the hydro companies want to be able to measure it, as they need larger capacity systems to compensate for aparent power. They may or may not be charging for it yet, i wont know till i see my next bill as mine was just installed.

Steve

[sphelps]

Smart meters can measure apparent power and therefore a power factor for the whole house. Pretty sure any more modern digital meter probably can as well, smart or not. But they don't charge residential for apparent power, plain and simple. The meters are more accurate and measure all the brief high start up power generated by larger appliances which previous analog meters couldn't measure. This is one reason you'll see an increase. Other increases will result from peek time billing if applicable. Power companies will sometimes even list your house PF and apparent power in kVA on your bill but they won't charge you for it.

I'm sure a few people already using smart meters in BC can confirm this for you.