Power Factor for AC Pumps

[sphelps]

According the producers of the energy monitor:

In AC power measurements, there actually three separate power components that can be measured:

Apparent Power: Measured in VA (volt - amperes). This is measured by taking the RMS voltage and RMS current readings and multiplying them together. This is what the eMonitor reports for power. All electrical circuits must be sized to handle apparent power because instantaneously, this is the maximum amount of power that can be flowing in a circuit.

Real Power: Measured in watts. This is the actual power that is being consumed by the load. This is what the utility company measures on the meter, as is what customers see on their electrical bill.

Reactive Power: This is kind of like imaginary power. It is really the difference between the Apparent Power and the Real Power. It is power that flows back and forth while the voltage and current are out of phase and is caused by the inductive load. Your utility company does not charge for reactive power, but it must handle reactive power, and reactive power does cause real current to run in your wires, and can generate heat. Reactive power is measured in VAR (volt - amperes reactive).

[mrhasan]

Originally Posted by sphelps

According the producers of the energy monitor:

Yap that's right. Like I said in the very beginning, the utility companies either consider pf=1 or maybe they just do some calculations to find a relative pf for the houses to multiply the RMS volt and current. The meter's simply can't find the individual PF of each appliances. Alongside, households doesn't generally have heavy PF lowering stuffs and hence its more or less above 0.9. Two or three pumps may have low PF in your house but in the end, it won't effect much to the pf of your whole house.

I have sent an email to enmax regarding this. The theory and the claims are just not going through and would love to clear it up too.

Another thing, if possible, if to measure the resistance of the motor (disconnect it and then measure) and then putting in the current (1.85) and resistance into the formula:
I^2/R.

[sphelps]

Well my understanding of AC power isn't great, not my specialty by a long shot. However it seems obvious to me that the term reactive power (the difference between apparent and real) when referred to "imaginary power" isn't something you're going to billed for. It's not being used despite the fact it goes through the circuit. While I might find it amusing to see a line on my power bill that said "Imaginary power usage = 958 kWh (this is the power you didn't use)" I just can't see it.

It's why everything online states a utility meter that measures in kW measures real power and not apparent power. It's clear power factors have virtually zero impact on your power bill which is why all those power factor compensation devices are a scam, also well documented.

I've also sent an inquiry to Enmax and GE (meter manufacturer) for conformation.

[mrhasan]

Originally Posted by sphelps

Well my understanding of AC power isn't great, not my specialty by a long shot. However it seems obvious to me that the term reactive power (the difference between apparent and real) when referred to "imaginary power" isn't something you're going to billed for. It's not being used despite the fact it goes through the circuit. While I might find it amusing to see a line on my power bill that said "Imaginary power usage = 958 kWh (this is the power you didn't use)" I just can't see it.

It's why everything online states a utility meter that measures in kW measures real power and not apparent power. It's clear power factors have virtually zero impact on your power bill which is why all those power factor compensation devices are a scam, also well documented.

I've also sent an inquiry to Enmax and GE (meter manufacturer) for conformation.

Please do post what they say. It will help me get my theories straight too.

World should revert back to DC grids like Edison's time. AC stuffs are just too complicated

[mrhasan]

Alright Steve you don't have to break the motor. I came across an energystar article and they say that in NA grid system, if you have a low pf equipment in domestic facility, you draw in more current but you are only charged for the amount of power that you are consuming and the extra power due to the charge is actually put into the penalty of the industries who have to pay for pf corrections.

So I guess you are actually getting charged for 82W :P

Sorry for the confusions; sometimes theory and practical stuffs doesn't match I will still post the response I get from enmax.

[sphelps]

Originally Posted by mrhasan

Alright Steve you don't have to break the motor. I came across an energystar article and they say that in NA grid system, if you have a low pf equipment in domestic facility, you draw in more current but you are only charged for the amount of power that you are consuming and the extra power due to the charge is actually put into the penalty of the industries who have to pay for pf corrections.

So I guess you are actually getting charged for 82W :P

Sorry for the confusions; sometimes theory and practical stuffs doesn't match I will still post the response I get from enmax.

Good news so far, I'll wait for conformation from Enmax before celebrating though

[mrhasan]

Originally Posted by sphelps

Good news so far, I'll wait for conformation from Enmax before celebrating though

I am feeling bad for someone out there who is paying more because of your motor having low pf

[sphelps]

Originally Posted by mrhasan

I am feeling bad for someone out there who is paying more because of your motor having low pf

I still don't think it works that way, the extra current isn't lost. The only losses are from heat resulting from the difference in current that feeds through the lines plus some very minor losses in the pump which you would experience with most devices. The extra current flows back to the source. Large industries are sometimes penalized for low power factors due to the provider having to supply higher currents and accept higher losses due to cable inefficiency. In residential the losses are minimal and probably absorbed in general as delivery charges.

The real advantage of high power factors is the ability to design lower powered circuits, it really has very little to do with efficiency.

And before you curse me, measure your own pumps many home appliances such as washing machines are known to have very low power factors. And while I'm still really surpirsed at the number for these expensive pumps at the end of the day at least they don't cost that much to run and I'd still rank then significantly higher in quality over the wavelines I have as well.

[sphelps]

Funny story, I just got a phone call from some direct energy provider wanting me to switch to them for electricity. I asked if they'll charge me for reactive power and she said she didn't know. I then asked how can you expect me to switch if you can't even tell me if I'll be billed for the imaginary power my pumps use. She hung up..

[sphelps]

Originally Posted by mrhasan

Yap that's right. Like I said in the very beginning, the utility companies either consider pf=1 or maybe they just do some calculations to find a relative pf for the houses to multiply the RMS volt and current. The meter's simply can't find the individual PF of each appliances. Alongside, households doesn't generally have heavy PF lowering stuffs and hence its more or less above 0.9. Two or three pumps may have low PF in your house but in the end, it won't effect much to the pf of your whole house.

I have sent an email to enmax regarding this. The theory and the claims are just not going through and would love to clear it up too.

Another thing, if possible, if to measure the resistance of the motor (disconnect it and then measure) and then putting in the current (1.85) and resistance into the formula:
I^2/R.

That's really not what my quote said by the way, but at this point we'll have to agree to disagree until we get conformation either way.