heat sinks and alt repair question

Wen Yen Chan chanwe at ecf.utoronto.ca
Tue Sep 22 12:12:53 GMT 1998


Hello,

At work we use Locktite Output compound or Wakefield Delta Bond. Both
brands are a little expensive but you get what you pay for. Keep in mind
that both of these compounds are really permanent. You will need to use a
heat gun or blow torch to remove the stuff if you make a mistake.

Wen

On Mon, 21 Sep 1998, T Hergen wrote:

> Any recommendation on a heat sink compound (brand name if possible) that
> won't run or dry out over time?  I wasn't happy with some stuff I got
> at the Shack (no surprise).
> 
> Thanks,
> Tom
> 
> On Mon, 21 Sep 1998 Terry_Sare at dell.com wrote:
> 
> > You will fry the diodes if you do NOT use heat sink compound, period. The HS
> > grease lowers the thermal resistance of the metal to metal contact. There is
> > plenty of metal to metal to conduct the current. If you think there is a
> > contact problem, measure it with a good DVM between the diode and the case.
> > Should be almost 0.
> > 
> > Again -- do not skip the heat sink compound.
> > 
> > ts
> > > -----Original Message-----
> > > From:	JRECPA at aol.com [SMTP:JRECPA at aol.com]
> > > Sent:	Monday, September 21, 1998 11:28 AM
> > > To:	diy_efi at efi332.eng.ohio-state.edu
> > > Subject:	Re: heat sinks and alt repair qiuestion
> > > 
> > > In a message dated 9/21/98 9:12:19 AM US Mountain Standard Time,
> > > rbraun at mail.enter.net writes:
> > > 
> > > << The alt on my '91 GTA just puked, it's a CS-130 105 amp, I got it all 
> > >  apart and the way I see it the diode package grounds to the case 
> > >  through the heat sink compound.  I'm thinking the poor ground thus 
> > >  created is adding to the heat of the diode pack and helping to 
> > >  cause them to fail.   Should I leave heat sink compound off 
> > >  entirely?, or at the end where the output term connects? or add a 
> > >  ground wire?
> > >  
> > >  The base of the d-pack is 3/32" thick copper plate which mounts to 
> > >  the alum case of the alt.  Would a copper to alum. mount 
> > >  transfer electric and heat better with or without the heat sink goo?
> > >  
> > >  Any EE's want to give opinions?
> > >  
> > >  TIA,
> > >  Randy Braun     rbraun at enter.net
> > >  91  GTA
> > >  82 Firebird
> > >   >>
> > > Be sure to put plenty of heat sink compound back on the diode pack.
> > > 
> > > I'll bet that your alternator's back is blocked buy engine components
> > > that is why the diode pack is overheating, no air flow!
> > > 
> > > James
> > 
> 
> 




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