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Old 04-20-2009, 10:38 PM   #1009 (permalink)
MPaulHolmes
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Join Date: Feb 2008
Location: Maricopa, AZ (sort of. Actually outside of town)
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Michael's Electric Beetle - '71 Volkswagen Superbeetle 500000
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The controller arrived! Ben sent it back really carefully! I bet that cost a lot. I'm going to save all the stuff when I send version 2 to him. OK, I've had the chance to do some analysis. Here's what I've done:

The free-wheel diodes are all good. The 3 mosfets closest to the B- post all had their legs which were connected to B- blown off. The worst damage was the mosfet closest to the B- post, and then 2nd worst was the 2nd, and then 3rd worst was 3rd. All other mosfets still had all their legs.


For those 3 mosfets, let's name the one closest to B- post MOSFET A, the next one, MOSFET B, and the last one MOSFET C.

For those 3 mosfets the resistors from gate to source had burned up on the source side of each one.

Mosfet A couldn't be checked if it had shorted from drain to source, since there was no source leg. It measured 170 Ohms from gate to drain.

Mosfet B is not failed shorted from drain to source, or gate to source, or gate to drain. It might still be good, but the source leg is mostly burned off.

Mosfet C IS failed shorted from drain to source, and gate to source measured 8 Ohms.

The 7 unharmed mosfets are not failed shorted. They are still good.

The control board seems completely unharmed. I removed the control board and powered it up on the oscilloscope, and it is behaving normally. I was able to control the pwm signal with a pot just fine.

MOSFET A

ANOTHER PICTURE OF MOSFET A

MOSFET B

MOSFET C
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Last edited by MPaulHolmes; 04-20-2009 at 11:23 PM..
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