Questions:

• Can you test 450V high ripple current caps with a any old desktop RCL meter?
• Has digikey shipped me faulty units?

Background:

I’ve gotten a couple of 660uF (not a typo, it’s some weird high ripple current caps for an outdoor AC unit) 450V caps to replace some that I decided were duds. Normally I only measure components when troubleshooting, but this being 20USD with vat devices I thought “what the heck, I better”.

The caps in question are chemi-con EKHJ451VSN661MA59M https://www.digikey.dk/en/products/detail/chemi-con/EKHJ451VSN661MA59M/17728502.

Method:

I’m using a Phillips PM6303A, which is a 1kHz RCL meter. Ambiant temp is approx 15°C. The caps have a 20% tolerance, so capacity should be >528uF, but when measuring both caps settle at approx 450uF after a little while. After 16hours it hasn’t deviated for the one cap I’ve left in over night. The dissipation factor, tan(δ), settled at 0.57, while the datasheet states that it shall be no greater than 0.2.

For comparison, the caps I thought was faulty, have been running for about 20years, with the same specs, but came out to 550uF and 0.3, and as the spec said 0.2 I decided to change them.