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BrianG · 10:45 AM

Sky will have to use whole new FETs for any higher voltage ESC since the ones they are using are only rated for 30v. The datasheet for the 125B's FETs is attached.

I'm not sure the thermal problems are because of a poor heatsink. Look at the MM; it's almost the same current rating and the HS is much smaller. The resistance of the MM is claimed to be 0.0003 ohms, while the 125B is claimed to be 0.0036 ohms. That might be part of why the MM runs cooler.

Sky can do a few things to make it cooler without using a large HS: Run FETs with lower RDSon, use more FETs to lower the overall RDSon, and make the FETs switch better (reduced slope, not increase in speed).

I really don't think they will allow internal epoxy being used because it won't allow them to take it apart to fix it.

Edit: Forgot to attach the datasheet. :dft009:

	(#9)
BrianG RC-Monster Admin Offline Posts: 14,609 Join Date: Nov 2005 Location: Des Moines, IA	02.05.2007, 12:31 PM Sky will have to use whole new FETs for any higher voltage ESC since the ones they are using are only rated for 30v. The datasheet for the 125B's FETs is attached. I'm not sure the thermal problems are because of a poor heatsink. Look at the MM; it's almost the same current rating and the HS is much smaller. The resistance of the MM is claimed to be 0.0003 ohms, while the 125B is claimed to be 0.0036 ohms. That might be part of why the MM runs cooler. Sky can do a few things to make it cooler without using a large HS: Run FETs with lower RDSon, use more FETs to lower the overall RDSon, and make the FETs switch better (reduced slope, not increase in speed). I really don't think they will allow internal epoxy being used because it won't allow them to take it apart to fix it. Edit: Forgot to attach the datasheet. :dft009: Last edited by BrianG; 07.14.2008 at 10:45 AM.