Capacitors getting hot

Discussion in 'General Electronics Chat' started by surfline, May 5, 2010.

  1. surfline

    Thread Starter Active Member

    Aug 12, 2009
    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?

  2. Bychon


    Mar 12, 2010
    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 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 :)
  3. rjenkins

    AAC Fanatic!

    Nov 6, 2005
    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.