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Old 07-11-2010, 12:00 AM   #3540 (permalink)
Mark Weisheimer
Join Date: Aug 2009
Location: Columbus Ohio
Posts: 62
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Originally Posted by voltmatic automaton View Post
Hi there,
i will try desoldering a gate resistor and let you know the value,
Hi VA,

No need to do that now.
I read your DIYEC post and found that the gate drive
resistors are 200 ohms. Quasar showed tacking another
200 ohm resistor onto the bottom of the original resistors.
That would make them 100 ohm, so you might want to
tack on an even lower value, such as 50 or 75 ohm.
I only suggest the tacking on as I sometimes find that
boards can only handle so much soldering/de-soldering
and doing it several times can lead to lifted circuit
traces. Who needs that problem?

I'd also recommend that you use twisted pair wire
to connect the gate drive from the Revolt control board
to the LogiSystem power board. (from a CAT5/6 cable)

The LS design has quite a lot in common with the Curtis controllers.
So, the TIP41C might be part of a voltage regulator to power the logic board.

I'm wondering if the IRFI620G is being used as a gate driver.
Can you tell where the circuit traces go from it?
It might also be part of a switch or etc that is no longer used
when the control board is removed.

My belief is that the Revolt control board has enough gate drive
to work with your LS power board.

Another thought here too....The heat could be coming from the
diodes. You could use a non-contact laser thermometer
to aim it at the bodies of the IGBT's and diodes to see where the
actual heat is coming from. Do you have one or do you know anyone
who could lend you one to test with? Or even better, use
an infrared camera if you have a relative who is the Fire Chief!
You did say that it got too warm when driving above 45 mph
so it is most likely the IGBT's, but I'd check it out if it was not
too difficult.


Last edited by Weisheimer; 07-11-2010 at 12:44 AM.. Reason: Read the post on DIYEC, it had helpful info.
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