How to determine how many BTU's are given off by an electric

Guest
Hello,

I have an electric pool pump and am trying to figure out how many
BTU's are given off during normal operation (let's say 1 hour). The
specs are as follows:

1hp
RPM 3450
230v @ 7.5 amps
0.75kw/hr

I was told that there should be some formula to find this out; however
I cannot seem to find it. Any help would be great.

Thanks,
Doug
 
dgreene@ddmtechs.com wrote:
Hello,

I have an electric pool pump and am trying to figure out how many
BTU's are given off during normal operation (let's say 1 hour). The
specs are as follows:

1hp
RPM 3450
230v @ 7.5 amps
0.75kw/hr

I was told that there should be some formula to find this out; however
I cannot seem to find it. Any help would be great.
Click to expand...
Based on normal motor efficiency around 75 to 80%, you can
probably estimate that the motor will produce a waste heat
of about 1/4 of its rated mechanical output. A horsepower
is 770 watts, so the waste heat is about 770/4 about 200
watts goes into the air cooling the motor. Of course all
the mechanical output also gets converted to heat in the
pool water as friction, so about 770 watts goes into the water.

--
Regards,

John Popelish
 
On Fri, 25 Jan 2008 09:00:13 -0800 (PST), dgreene@ddmtechs.com
wrote:

Hello,

I have an electric pool pump and am trying to figure out how many
BTU's are given off during normal operation (let's say 1 hour). The
specs are as follows:

1hp
RPM 3450
230v @ 7.5 amps
0.75kw/hr

I was told that there should be some formula to find this out; however
I cannot seem to find it. Any help would be great.
Click to expand...
---
1 kilowatt-hour = 3413 BTU


--
JF
 
"John Fields" <jfields@austininstruments.com> wrote in message
news:d27kp3d4787ojumd7con4mne029bnd8le6@4ax.com...
On Fri, 25 Jan 2008 09:00:13 -0800 (PST), dgreene@ddmtechs.com
wrote:
Hello,
I have an electric pool pump and am trying to figure out how many
BTU's are given off during normal operation (let's say 1 hour). The
specs are as follows:
1hp
RPM 3450
230v @ 7.5 amps
0.75kw/hr
I was told that there should be some formula to find this out; however
I cannot seem to find it. Any help would be great.

1 kilowatt-hour = 3413 BTU
Click to expand...
You need to be careful as to what you refer .........

BTU = Board Of Trade Unit = Kilowatt Hour

BThU = British Thermal Unit, which ISTR is energy needed to
raise 1 lb of water by 1 degree F.
 
"John Popelish" <jpopelish@rica.net> wrote in message
news:sN2dnZtSfcoVigfanZ2dnUVZ_oaonZ2d@comcast.com..

<snip>.
A horsepower is 770 watts,
Click to expand...
The usual conversion factor that I have seen is ! hp = 746 watts. I did a
check in wikipedia and they give 745.699 871 582 270 22 watts. They
also give different types of horsepower, (imperial, metric) with slightly
different conversion factors (746 vs 736 watts).

http://en.wikipedia.org/wiki/Conversion_of_units#Power
 
On Fri, 25 Jan 2008 17:57:38 -0000, "Anonymous." <me@privacy.net>
wrote:

"John Fields" <jfields@austininstruments.com> wrote in message
news:d27kp3d4787ojumd7con4mne029bnd8le6@4ax.com...
On Fri, 25 Jan 2008 09:00:13 -0800 (PST), dgreene@ddmtechs.com
wrote:
Hello,
I have an electric pool pump and am trying to figure out how many
BTU's are given off during normal operation (let's say 1 hour). The
specs are as follows:
1hp
RPM 3450
230v @ 7.5 amps
0.75kw/hr
I was told that there should be some formula to find this out; however
I cannot seem to find it. Any help would be great.

1 kilowatt-hour = 3413 BTU


You need to be careful as to what you refer .........

BTU = Board Of Trade Unit = Kilowatt Hour

BThU = British Thermal Unit, which ISTR is energy needed to
raise 1 lb of water by 1 degree F.
Click to expand...
---
Hmm...

BTU as an acronym for "British Thermal Unit" is hardly deprecated,
as indicated by Wikipedia at:

http://www.wisegeek.com/what-is-a-btu.htm

and Webster's at:

http://www.websters-online-dictionary.org/definition/BTU

Moreover, from the context of the article it should have been
abundantly clear that the OP was asking for a conversion from
watt-hours to British Thermal Units, so what's your point?


--
JF
 
On Jan 25, 8:00 pm, dgre...@ddmtechs.com wrote:
Hello,

I have an electric pool pump and am trying to figure out how many
BTU's are given off during normal operation (let's say 1 hour). The
specs are as follows:

1hp
RPM 3450
230v @ 7.5 amps
0.75kw/hr

I was told that there should be some formula to find this out; however
I cannot seem to find it. Any help would be great.

Thanks,
Doug
Click to expand...
Answering this question per the above info.
1) 230 x 7.5 = 1725 watts.
2) But one horespower is 746 watts.
3) So item one maybe the starting current?
Using that it IS a 'one' horsepower motor which at 230 volts will have
a 'running' current of 746/230 = 3.2 amps.
4) If the motor has typical efficiency of 75%; 25% of the (one
horsepower) wattage is dissipated as electrical heat.
5) 746 x 0.25 = 186.5 watts.
6) 1000 watts = 3413 BTU (British Thermal Units).
7) Therefore 186.5/1000 x 3413 = 636.5 BTU, dissipated as electrical
heat by the motor itself.
 
On Jan 25, 1:33 pm, "Dan Coby" <adc...@earthlink.net> wrote:
"John Popelish" <jpopel...@rica.net> wrote in message

snip>.
A horsepower is 770 watts,

The usual conversion factor that I have seen is ! hp = 746 watts. I did a
check in wikipedia and they give 745.699 871 582 270 22 watts. They
also give different types of horsepower, (imperial, metric) with slightly
different conversion factors (746 vs 736 watts).

http://en.wikipedia.org/wiki/Conversion_of_units#Power
Click to expand...
By the time i realized that I had remembered the factor wrong, others
had already given the correct value.

The point to make is that just entering BTU or HP into Google gives
the conversion factors at the top.

But thanks for the help.
 
On Jan 26, 10:29 pm, jpopel...@rica.net wrote:

The point to make is that just entering BTU or HP into Google gives
the conversion factors at the top.
Click to expand...
Correction: you have to enter [horsepower] to get the conversion
factor.
 
On Jan 25, 7:23 pm, terryS <tsanf...@nf.sympatico.ca> wrote:
On Jan 25, 8:00 pm, dgre...@ddmtechs.com wrote:



Hello,

I have an electric pool pump and am trying to figure out how many
BTU's are given off during normal operation (let's say 1 hour). The
specs are as follows:

1hp
RPM 3450
230v @ 7.5 amps
0.75kw/hr

I was told that there should be some formula to find this out; however
I cannot seem to find it. Any help would be great.

Thanks,
Doug

Answering this question per the above info.
1) 230 x 7.5 = 1725 watts.
2) But one horespower is 746 watts.
3) So item one maybe the starting current?
Using that it IS a 'one' horsepower motor which at 230 volts will have
a 'running' current of 746/230 = 3.2 amps.
4) If the motor has typical efficiency of 75%; 25% of the (one
horsepower) wattage is dissipated as electrical heat.
5) 746 x 0.25 = 186.5 watts.
6) 1000 watts = 3413 BTU (British Thermal Units).
Click to expand...
Just FYI, that should be 1000 Watt-hours = 3413 BTU

7) Therefore 186.5/1000 x 3413 = 636.5 BTU, dissipated as electrical
heat by the motor itself.
Click to expand...
.... per hour.

Mark
 
On Jan 27, 7:02 am, redbelly <redbell...@yahoo.com> wrote:
On Jan 25, 7:23 pm, terryS <tsanf...@nf.sympatico.ca> wrote:





On Jan 25, 8:00 pm, dgre...@ddmtechs.com wrote:

Hello,

I have an electric pool pump and am trying to figure out how many
BTU's are given off during normal operation (let's say 1 hour). The
specs are as follows:

1hp
RPM 3450
230v @ 7.5 amps
0.75kw/hr

I was told that there should be some formula to find this out; however
I cannot seem to find it. Any help would be great.

Thanks,
Doug

Answering this question per the above info.
1) 230 x 7.5 = 1725 watts.
2) But one horespower is 746 watts.
3) So item one maybe the starting current?
Using that it IS a 'one' horsepower motor which at 230 volts will have
a 'running' current of 746/230 = 3.2 amps.
4) If the motor has typical efficiency of 75%; 25% of the (one
horsepower) wattage is dissipated as electrical heat.
5) 746 x 0.25 = 186.5 watts.
6) 1000 watts = 3413 BTU (British Thermal Units).

Just FYI, that should be 1000 Watt-hours = 3413 BTU

7) Therefore 186.5/1000 x 3413 = 636.5 BTU, dissipated as electrical
heat by the motor itself.

... per hour.

Mark- Hide quoted text -

- Show quoted text -
Click to expand...
Yup. Just revisited this thread. Your right man. 1000 watt hours it
is.
i.e. One kilowatt hour or one 'unit' in some jurisdictions.
 
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