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Old 04-01-2014, 02:35 PM   #6378 (permalink)
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Originally Posted by MPaulHolmes View Post
The nice thing is, we can choose any frequency from 0 to like 16kHz (without spread spectrum switching), but 16KHz would probably produce too much heat under high power situations. Damien could probably comment on how the 8KHz sounds when it's in the engine compartment. I think he uses 8KHz with his IGBTs. I just downloaded 10KHz, and that seemed significantly "quieter". It's all just a trade off. Higher switching frequency = more heat. There's really no downside to spread spectrum switching, other than the annoyance of a little extra time of writing code for software PWM. Maybe I should do that. Oh heck, let's try it all!
Okay looks like there are some options, I thought from your earlier post that 8K hz as high as the ights could go.

Speaking of heat. I was looking at mounting the controller in my truck. Easiest option is to mount on 3/4" spacers above a board with a fan recessed in the board. The fan would blow air through the 3/4" gap between the bottom of the controller and the board. Do you think that will work or is a heatsink going to be needed?
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