Heat load calculation - Motors

[Peter_1]

In many pre-filled heat load forms and in almost all school books where they explain how to calculate a heat load, you can read that you have to take the rated power as a heat load.
So a 600 W motor will dissipate 600 W.
This is not correct in my opinion.
Is it therefore more correct to state that a motor of 600 W with a power factor of 0.9 has an apparent power of 666 W of which 66 W is transfered as heat and can be considered as a heat load? If you should touch a motor of 600 W, you should burn your hand very heavily :-)
I instruct my students that it is 66 W instead of 600 W although it's otherwise stated in my technical books. Any comments?

[mikeref]

Power factor comes down to the loss of energy when transforming one type of energy into another.
The losses are transferred to the next device so the motor does not have the burden of extra load beyond it's rated capacity.
Good question Peter!! ;)

[al]

I only ever came across one instance of this, close control room, deviation allowed of 0.5c, evaporator fans mounted externally and ducted in, designer never allowed for the fan motor load (about 800w), heat from motors was enough to drive room out of spec.
i really don't see it as an issue, all loads are oversized, so would this compensate for any oversight?

al

[monkey spanners]

The energy has to go somewhere, some of the mechanical work done by the motor gets turned into heat, a pump will warm up the fluid it is moving for example.

[Peter_1]

The energy of a motor on i.e. a belt is- as I see it - transformed to kinetic energy, some potential energy if at different height, some in sound energy, some in light energy but to my opinion all the losses are finally converted to heat.
Al, this question is of big importance because I need to fit this theory into another theory of big importance for the moment.
But what about a printer , a screen/monitor, a PC, a battery charger, ... I think all this is transfered to heat but it is never at full load and full power.

[install monkey]

http://www.engineeringtoolbox.com/electrical-motor-heat-loss-d_898.html