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I plowed through this thread over the course of about a week. I'm now swimming through the AC Controller thread. I have seen guestimations where you should only stress a MOSFET to about 1/2 it's amp rating. In fact, when you look at the data sheet for a MOSFET or IGBT, it includes a Watts rating! Watts = Volts X Amps. What I found is that you can only achieve the rated amps if the voltage drop is about 2-3 volts. Working with 144 volts (or higher in some cases), the watts blow MOSFETs rated for far more than the amp current being drawn.
Example: 144 volts, 100 amps -- 144 X 100 = 14400; 14.4 kW yes? The MOSFET/IGBT only sees that high energy flow for microseconds until things settle, but it still sees it. I went through a bunch of my MOSFET inventory, not having a clue why I was blowing them up one after another, with far lower amp flow than they were rated for.
The answer is -- Look at the Watts rating for the MOSFET/IGBT!
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Recovering Gasaholic
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