On Tue, Aug 28, 2001 at 02:28:24PM +0100, John Walshe wrote:
> Why don't you make use of all of that metal in the drive path?

Because it's spinning. The motors are direct mounted to the wheels and
are outboard of the platform.

>Assuming the FETs/Transistors are isolated devices...

Any way to make that assumption? In almost every case that tab on a TO220
case is connected to something. I was thinking that each half of the HBridge
could share a sink because the tabs are connected to the collectors and the
collectors are shared.

> the metal framework should provide a
> reasonable heatsink, without too much trouble. If the above are not isolated
> devices then you will have to put a mica strip(or modern equivalent) between
> the device and the metal.

Now that's an idea. Would anyone care to explain how mica gives good heat
coupling while maintaining electrical isolation?

Thanks for the info.

BAJ

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