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BrianG · 10.24.2010, 03:58 PM

Well, there are 36 FETs on the visible side which is pretty typical for a ~150A rated ESC. If there were the same number under the heatsink, that would be 72 FETs, and would probably be rated closer to 250A if not more. So, I would guess the heatsink is simply attached to the PCB and draws heat from the visible FETs via the circuit board. Might seem like a waste, but having the heatsink not attached directly to the FETs makes it more durable IMO (any shock on the sink doesn't affect the FETs as much), and would negate any chance of the heatsink not sitting flush on all the FETs (each one may not be soldered exactly flat).

From what I've seen of these HW ESCs, they seem pretty decent. It's just too bad their programming is limited and the software isn't the best IMO (poor slow speed performance). Programming-wise, they remind me of old-school Quark ESCs without the smooth low speed action.

I will say the FET arrangement/layout looks a bit odd. It's like they just plunked them down wherever there was room. Typically, they are arranged in specific banks/rows to make circuit paths as short and clean as possible to reduce copper losses. But whatever, I'm not an ESC designer...

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BrianG RC-Monster Admin Offline Posts: 14,609 Join Date: Nov 2005 Location: Des Moines, IA	10.24.2010, 03:58 PM Well, there are 36 FETs on the visible side which is pretty typical for a ~150A rated ESC. If there were the same number under the heatsink, that would be 72 FETs, and would probably be rated closer to 250A if not more. So, I would guess the heatsink is simply attached to the PCB and draws heat from the visible FETs via the circuit board. Might seem like a waste, but having the heatsink not attached directly to the FETs makes it more durable IMO (any shock on the sink doesn't affect the FETs as much), and would negate any chance of the heatsink not sitting flush on all the FETs (each one may not be soldered exactly flat). From what I've seen of these HW ESCs, they seem pretty decent. It's just too bad their programming is limited and the software isn't the best IMO (poor slow speed performance). Programming-wise, they remind me of old-school Quark ESCs without the smooth low speed action. I will say the FET arrangement/layout looks a bit odd. It's like they just plunked them down wherever there was room. Typically, they are arranged in specific banks/rows to make circuit paths as short and clean as possible to reduce copper losses. But whatever, I'm not an ESC designer...