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

On Jan 25, 7:23 pm, terryS <tsanf...@xxxxxxxxxxxxxxx> wrote:
On Jan 25, 8:00 pm, dgre...@xxxxxxxxxxxx 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
.

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