VEMS Community Forum

General Category => General Discussion => Topic started by: bcool on November 01, 2007, 12:53:23 AM

Title: IGBT/FET clamping to case?
Post by: bcool on November 01, 2007, 12:53:23 AM
What are you using to clamp your IGBTs/FETs to the case? I'm just curious to see if theres anyting creative out there thats home-made. I tried little strips of aluminum with nuts attached but there's just not enough room in the case for them. I was thinking of re-cutting new peices of aluminum, drilling small holes in it and trying a screw type fastener next time
Title: Re: IGBT/FET clamping to case?
Post by: [email protected] on November 01, 2007, 07:55:01 AM
The assembled ones come with strips of aluminim with threaded holes, the holes line up to the screw holes in the outside of the case, its a bit of a fiddle to get them in place but once its done its a good clamp.
Make sure you use insulation sheet though.

Rob
Title: Re: IGBT/FET clamping to case?
Post by: bcool on November 01, 2007, 08:48:30 AM
Yeah my case has the sheet in it and i plan to use thermal compound normally used for computer CPU's. I just realized that at the very bottom of the case page on the webshop that they have the little strips of metal. Oh well i'll finish up my home-made ones tomorrow.
Title: Re: IGBT/FET clamping to case?
Post by: [email protected] on November 01, 2007, 09:15:03 AM
No need to use that thermal compound, those sheets are perfect for the job without it.  Magic stuff, it conducts heat but insulates electricity.
Title: Re: IGBT/FET clamping to case?
Post by: GintsK on November 01, 2007, 06:12:55 PM
Quote from: [email protected] on November 01, 2007, 07:55:01 AM
The assembled ones come with strips of aluminim with threaded holes, the holes line up to the screw holes in the outside of the case, its a bit of a fiddle to get them in place but once its done its a good clamp.
Make sure you use insulation sheet though.

Rob
Disagree. It do job only if screws is not overtightened (it is very easy to do!). Otherwise middle switches in the row stays presureless.  I look for much foolproof solution.

On the other hand: did someone find some heating if dwell time is correct?

Gints
Title: Re: IGBT/FET clamping to case?
Post by: bcool on November 02, 2007, 09:42:27 AM
I noticed the bowing when i did mine tonight. I ended up making them out of strips of (what appears to be) 2mm aluminum and i used little screws that fit perfect in the cases beveled holes and drilled holes in the thin metal strips.  all my igbt's are nice and snug, those are the guys I'm most concerned about.

I really wish we just ended up with these cases instead:

(http://www.vems.hu/files/hackish/cncv2.jpg)
(http://www.vems.hu/files/hackish/CnC/ecucase2.jpg)