Capacitors getting hot

Thread Starter

surfline

Joined Aug 12, 2009
39
In a high power motor control project I'm working on, certain capacitors are getting fairly hot, around 75 degrees Celcius and increasing.

Is heat-sinking capacitors a common procedure? Does parallelizing them evenly distribute the load? Any other suggestions?

Thanks.
 

Bychon

Joined Mar 12, 2010
469
Paralleling capacitors is commonly used to lower ESR (equivalent series resistance) and it very much helps radiate the waste heat. There is a limit to how much ripple current capacitors can carry without overheating, and I've actually had to deal with that...by paralleling caps.

As for heat sinking...couldn't hurt...unless their cans are at different voltages and get shorted together. Don't short the cases together, and go get a fan :)
 

rjenkins

Joined Nov 6, 2005
1,013
You can get different grades of capacitors with the same values.

Look for 'High Ripple Current' and 'Low ESR' types to minimise heat production, and also look at the temperature rating - it could be 70' or 105', the high temperature ones will have a longer life for any given conditions.

Definitely use several in parallel to distribute the losses.

If they are running noticably warm, the life will be drastically reduced. For some types the life at maximum temperature is only 5000 hours - less than a year.

The same cap may last decades if running cool.
 
Top