25-09-2024, 11:38 AM
Hi Ian
The 100 Watt rating for this type of metalclad resistor applies when it's bolted to a heatsink. If you choose to leave it sitting in free air the rating is more like 20 Watts. That should still be fine though, the reduced field current through it when it's in use will be roughly 1 amp and the dissipation will only be about 2 watts. This means the surface temperature won't be too high and you can mount it wherever it's convenient.
The 100 Watt rating for this type of metalclad resistor applies when it's bolted to a heatsink. If you choose to leave it sitting in free air the rating is more like 20 Watts. That should still be fine though, the reduced field current through it when it's in use will be roughly 1 amp and the dissipation will only be about 2 watts. This means the surface temperature won't be too high and you can mount it wherever it's convenient.