Re: dumping a lot of heat

On 2024-12-04 22:29, john larkin wrote:

I'm thinking about building a biggish rackmount dummy load box. It
would simulate series resistance and inductance. Part of the problem
is that it will need to dump a lot of heat.
 We are using copper CPU coolers on PC boards, which are great up to a
couple of hundred watts, but I'd like to do a kilowatt or two.
 https://highlandtechnology.com/Product/P945
 It would take a heap of expensive extruded heat sinks and fans to get
rid of a kilowatt. At 1 K/W, a pretty good heat sink, that's 1000 degC
temp rise.
 A small hair dryer can dump a kilowatt. So some sort of red-hot
nichrome coils and a vicious fan might work.
 I'd prefer to not use water.
 I wonder if there is some sort of runs-red-hot power resistor.
 

I once used a 2kW grill element as a surge current limit resistor, mounted in top of the 19" cabinet.
A thermal cutout (clixon) above it interrupted mains power (and issued an alarm) in case the shorting relay failed to close after 5 seconds.
The idea was to charge up all PSU input caps for a 10kW power system before enabling the outputs. Worked fine.
Arie