Hey, um, I seem to have a problem: I used an MKP type polypropylene cap for the snubber, which works nicely, except that... when I turn up the juice (namely 320VDC supply), it gets noticably warm and, after a while, swells! It's not a particularly beefy unit, but still, I count 30A peak and 9.4A RMS through the poor thing! It's probably good for 1, maybe 2A RMS tops.
So I turn to my handy Mouser Catalog 634, and flip around to, oh, Cornell Dubilier 935's. But the size I need (~0.1uF) starts at 1000VDC, and even then it's "only" rated for 8.something A RMS. And if I'm going to get one of those expensive suckers, it's got to be rated for full power, which is at least double the current, and they aren't!
Of course, I could go with one of those so-called "IGBT Snubber" capacitors, but they're made for modules, and I don't have any modules.
So what do you all use for snubbers when it's a measly 10kW or less? I'm leaning towards smaller MKPs, something like the Epcos high pulse rated
630V 0.033uF (see data at Digikey), and paralleling a bunch, like I did with every other damn cap in this project, but I can't help but feel like I'm missing something obvious here...Tim
-- Deep Fryer: A very philosophical monk. Website @
anyway,
stuff.