alt.engineering.electrical

"Palindrome" wrote in message
news:3ZU_i.152062$Nb1.132967@fe01.news.easynews.com...
> TE Chea wrote:
>> I notice electrical & electronic devices ( if hot ) all
>> work better if cooled.
>> Thanks for any advice.
>>
>>
> All equipment is designed to work within a certain range of environmental
> conditions. Operating outside that range will generally result in
> immediate failure or a dramatic decrease in reliability. Even within the
> range there can be wide variations in expected life and efficiency.
>
> As for your motor, if cooling is required to keep its internal
> temperatures to within design limits, then indeed it is highly likely that
> it could spin faster and/or use fewer amps if cooled.
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Not so--- all that cooling will do is allow the motor to be run at above its
rated load torque-either continuously or for a longer time without
overheating.
The current is dependent on load torque which may or may not depend on speed
(voltage related).
All cooling will do is extract heat more effectively - it will not affect
the production of heat.

Cooling will not allow faster "spinning" nor will it reduce the current. It
will allow higher load torques resulting in higher currents without
excessive temperatures (and lower speeds depending on the motor
characteristics).
These are opposite to what you have said. In general at lower currents and
higher speeds, the need for cooling is reduced.

Motor considerations regarding performance and cooling are quite different
from those of solid state electronics. Tom Grayson has it right.

--

Don Kelly dhky@shawcross.ca
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