watt

[engrav]

Hi
How can I determine watts of my pump? Is WhisperFlo WFE4.
I read some TFP postings but still confused.
Called Pentair. Said they do not know. I should measure volts and amps and multiply.

 

[Bama Rambler]

The best way to do it is to actually measure the volts and amps and use that to figure it out. If you use the nameplate numbers you're not getting the actual operating numbers.

 

[toolkit]

As an electrical engineer, I have to jump in here. If you are wondering how much it costs to run the pump, then simply multiplying voltage and current will give you a misleading answer. A typical electric motor has a relatively poor power factor (maybe somewhere between 0.6 and 0.8), and therefore the apparent power (V*I) will be rather larger than the real power (V*I*PF). The electric company only charges you for the real power you use. There are some losses in the wires between the electric meter and the load (in this case the pump motor), and having extra current there can add to the real power consumed (because those loses are resistive) - but that would be really small for a typical pool pump.

To really find out the power consumption, you need a watt meter. If you don't have that, then if you have an oscilloscope, you can calculate the power factor using the phase difference between the voltage and current curves. But I'm guessing you may not have an oscilloscope available either. So without a watt meter or an oscilloscope, perhaps your best bet is to just estimate the power factor (I would guess 0.75, realizing that it might be lower) and then calculated the power as Voltage (Volts RMS) * Current (Amps RMS) * PF.

 

[engrav]

interesting
electrician is coming to discuss generator
will ask that he bring watt meter as well
thanks

 

[JamesW]

Toolkit makes a good point about the power factor.

Many new pumps use a run capacitor, which corrects the phase shift caused by an induction motor. Therefore, the pump might have a power factor very close to 1.0. I think that all Whisperflo pumps use a run capacitor.

Either way, as toolkit said, the best way to tell is to use a wattmeter, or a power quality meter, which can measure volts, amps and real watts, and tell you your actual power factor.

 

[mas985]

A couple of other options to determine energy use:

1) Use the house power meter. Take a reading with the pump on and off and the energy use is the difference. This can be done with analog meter as well but it requires counting the turns.

2) A rough estimate for the WFE 4 is about 1800 watts for 2" plumbing and 1700 watts for 1.5" plumbing.

3) I get can get a closer estimate with a detailed description of your suction side plumbing (pipe sizes, lengths, number runs), filter pressure and pump height relative to the water level.

 

[engrav]

A couple of other options to determine energy use:

1) Use the house power meter. Take a reading with the pump on and off and the energy use is the difference. This can be done with analog meter as well but it requires counting the turns.

2) A rough estimate for the WFE 4 is about 1800 watts for 2" plumbing and 1700 watts for 1.5" plumbing.

3) I get can get a closer estimate with a detailed description of your suction side plumbing (pipe sizes, lengths, number runs), filter pressure and pump height relative to the water level.

thank you

1) person from the energy company did that yesterday with the meter; reported 3.5 kWh / hr so if 6hrs / day and 30 days then 3.5 * 6 * 30 or 630 kWh / mo and at say 10cents per then $63 per month

2) now say 1800 watts then 1800 / 1000 * 6 * 30 we have 324 kWh which does not match; wonder what is wrong?

3) cannot do this as was built in 1979 and all design long gone and I am a newbie

 

[JamesW]

person from the energy company did that yesterday with the meter; reported 3.5 kWh / hr

3.5 kW is not a realistic value for a 1 H.P pump. Can you get voltage and amperage measurements?

Note that voltage measurements need to be taken under load to account for voltage drop due to load.

Is the pump wired 120 or 240?

 

[engrav]

person from the energy company did that yesterday with the meter; reported 3.5 kWh / hr

3.5 kW is not a realistic value for a 1 H.P pump. Can you get voltage and amperage measurements?

Note that voltage measurements need to be taken under load to account for voltage drop due to load.

Is the pump wired 120 or 240?

wired 240
he used the meter, is digital with little ticks passing by
if I knew how to count ticks, I could go repeat the test
will scan the web to see if web says how to count ticks

 

[JamesW]

If you're using the house meter, you have to measure with the pump off and then on. You also have to make sure that all other power use stays the same. If any thing else changes, such as an electric water heater, or AC unit turning off or on, then the test won't be valid.

 

[engrav]

If you're using the house meter, you have to measure with the pump off and then on. You also have to make sure that all other power use stays the same. If any thing else changes, such as an electric water heater, or AC unit turning off or on, then the test won't be valid.

went to the house (house is unoccupied, dark, fridge on)
has digital meter
kh says to be 0.6
indicates meter runs in 80kw units / not 1kw units

turned on the pump
the indicator jumped rightward in 5 steps in 1min14sec; then returned to the left;
then waited for another cycle
the indicator jumped rightward in 5 steps again in 1min14sec; then returned to the left

turned off the pump
indicator jumped rightward in 5 steps in 8min42sec and returned left

what does all this mean? dunno, beyond my old brain, electrician coming Wed, hopefully can sort out

 

[engrav]

and
Jan Feb use 1600 kwh
Mar Apr used 1280 kwh
May Jun used 1440 kwh in the house

 

[mas985]

wired 240
he used the meter, is digital with little ticks passing by
if I knew how to count ticks, I could go repeat the test
will scan the web to see if web says how to count ticks

That sounds like an analog meter and not a digital. I think he just used the wrong conversion factor because half of 3500 watts or 1750 watts is about right.

If you can get the meter model#, you can look up the conversion factor.

 

[engrav]

[attachment=0:3hp7ttmw]DSC_9217.jpg[/attachment:3hp7ttmw]

wired 240
he used the meter, is digital with little ticks passing by
if I knew how to count ticks, I could go repeat the test
will scan the web to see if web says how to count ticks

That sounds like an analog meter and not a digital. I think he just used the wrong conversion factor because half of 3500 watts or 1750 watts is about right.

If you can get the meter model#, you can look up the conversion factor.[/quote]

is digital, see pic attached

little black lines under #'s tick by in 5 steps then return and start over; maybe this is one revolution of the analog disk
NOTE: multiply by 80 as per written in #, kh is 0.6

 

[mas985]

So my meter (similar to yours) shows the actual wattage. Why do you need to count the ticks?

 

[engrav]

So my meter (similar to yours) shows the actual wattage. Why do you need to count the ticks?

It reads in 80 kW jumps so the digital may not change for a day

 

[JamesW]

I think that your meter alternates between displays. All 8888s is to show that the display is working. Then it shows total kWh, then current power usage.

 

[engrav]

I think that your meter alternates between displays. All 8888s is to show that the display is working. Then it shows total kWh, then current power usage.

only two displays
1) 888's
2) total kwh used

but #2 is in 80kwh units so does not change often

the little black lines tick along throughout
am still confused about kWh consumption

electrician coming Wed

 

[JamesW]

Your power company or the meter manufacturer (Landis Gyr) should be able to tell you how to read the meter to get current power use.

 

[engrav]

[attachment=0:13i1mu3z]photo2.JPG[/attachment:13i1mu3z]

Your power company or the meter manufacturer (Landis Gyr) should be able to tell you how to read the meter to get current power use.

Can you post a picture of the meter with the other display?

sure, first is 8888 etc
second is attached, counts in 80kwh units so does not advance very often

I am thinking 6 jumps of the little bar is one beat (or one old analog rotation)
then on the web site <http://michaelbluejay.com/electricity/measure.html#beats>
enter 0.6 kh 2 beats in 148 seconds and multiply by 80 and get 2.3 kWh/hr
which suggests the pump is 2300 watts
2.3 kwh/hr for 6hrs for 30 days is 420 kWh / month, at about 10cents per, that is $42 per month
but still a little uncertain

electrician coming Wed