"terry" wrote in message
oups.com...
On Apr 17, 2:35 pm, Highland Ham
wrote:
Uncle Peter wrote:
Does reducing the resistance affect the wattage rating
of a power rheostat? I'd imagine it does, but I'm not
sure how it would be derated..

That's logical.
But just to nit-pick! :-)
Got one of those ceramic tubular adjustable slide resistors. Rated at
300 watts IIRC.
If I put the slider half way along I will have half the resistance
wire in the circuit and dissipating heat at full current rating;
correct?
But still the same thermal mass of ceramic and metal. So could one
perhaps argue that it might be 'slightly' (very slightly perhaps) a
little more than half the power rating. Probably nothing to have any
effect whatsoever in practice because one would not run a component at
maximum rating at any setting anyway?


Hi Terry

That's what I was wondering, the mass of the heatsink
the windings are on should have a bearing on
the wattage... Lacking manufacturer data I guess it
is a moot point and I'll take a conservative tack..

Pete