That would be the way to go. Lots of distributors sell mounting kits
for power transistors, which generally include the insulator. Check for
example DigiKey, Mouser, Jameco.

        If you can't use the existing metal, another way to go is an
aluminum channel underneath the board (assuming TO-220 or somesuch). Mount
the transistors on the bottom of the board, at a 90 degree angle so the
metal portion of the case makes contact with the aluminum. Crude ascii art
to illustrate concept:

          (board) ----------------
     (transistor)    *****
      (heatsink)  ================

In other words, you're sandwitching the transistor between the board and
heatsink. By mounting the transistors on the bottom, you don't have to worry
about interference with large caps and connectors. You can also buy finned
heatsink material and cut that to size; but I find plain aluminum channel
stock is cheaper, has a reasonably smooth surface finish, and works well in
most cases. You can probably get the channel stock through Grainger or
McMaster. You can make the heatsink as big/long as your board without adding
a lot of height.


> -----Original Message-----
> From: John Walshe [mailto:John.Walshe@INPACTMICRO.COM]
> Sent: Tuesday, August 28, 2001 9:28 AM
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: [OT]: How to heatsink a lot of power electronics?
>
>
> Why don't you make use of all of that metal in the drive
> path? Assuming the
> FETs/Transistors are isolated devices 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.
> John
>
> --
> http://www.piclist.com#nomail Going offline? Don't AutoReply us!
> email listserv@mitvma.mit.edu with SET PICList DIGEST in the body
>
>

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email listserv@mitvma.mit.edu with SET PICList DIGEST in the body