I don't have the 1N 4001specs, but automotive applications require more
careful attention to heat budgets. Because the ambient temperature is
higher within an engine compartment, you have to check whether the
semiconductor will remain within its operating temperature range while
handling the worst case current load. Extra heat sinking might be
necessary or the substitution of a diode with a higher temperature
breakdown limit. Heat will also shorten the life of a semiconductor, so
early failure is always a possibility if the wrong part is used. Don't
forget to use heat sink compound to make a good thermal coupling between
the component and any mountings or heat sinks. You can get is at Radio
Shack.
George
----------
> From: High Tech Coatings <htc@MNSi.Net>
> To: bricklin <Bricklin@autox.team.net>
> Subject: Re: Rick, more alternator stuff
> Date: Tuesday, October 31, 2000 6:23 AM
>
> Stephan:
> The diode I used was similar to a IN 4001 (only bigger) I can't remember
> what it was as too much time has passed but I'm sure it was nothing
special.
> AS for the cap I just Tapped it into the MSD power line near the box
(after
> the diode) to 'filter' out any wandering AC. layout was box
-diode-cap-car.
> As for cap design I used an automotive one any parts store will have a
> points style condenser for a Chev small block, just hook the wire to
power
> and ground the case. Any good sized electrolytic cap that can handle the
> heat and humidity under your hood in Miami should work just hook up the
pos
> end to the box and ground the neg. end.
> One more thing, make sure the wire going to the regulator that senses
> voltage has a good connection at both ends and goes directly to where it
is
> supposed to go without any 'taps' on it. If there is a draw form
somewhere
> on this line the regulator may be sensing the voltage drop and running
the
> alt to try to replace the charge. also make sure the reg. has a very good
> ground so it can sense voltage properly.
> What is the present voltage in the battery? where does it go while
running?
> hope this helps,
> Rick 2028/0539
> ----- Original Message -----
> From: alphachi <alphachi@writeme.com>
> To: <Bricklin@autox.team.net>
> Sent: Monday, October 30, 2000 11:17 PM
> Subject: Rick, more alternator stuff
>
>
> > Hi Rick,
> > The diode was a surplus one I had laying
> > around but one but one rated for about 120 volts and about five times
the
> > max amp draw of the MSD should work fine. for the capacitor I just used
an
> > old condenser from a points style distributor.
> >
> > What type, construction, and what rating do you recommend for the
MSD?
> > As for the condenser/cap, where did you put it in circuit?
> >
> > The alt installed is a custom wound one from AIS, and was built to put
out
> > over 100amps at 15v in a ford small case. This does compound any heat
> > problems. While the alt was over heating, the orginal power lead
which
> is
> > what, about #6- #8, was not even warm, which surprised me a little.
> >
> >
> > As for the adjustable regulator, it was recommended because of the
> distance
> > between the alt and batt and the HO alt, and the desire to run 14v.
I'd
> > like to run about 14v to insure a quick charge on the start/deep cycle
> > Optima batt which can take 15v, and to decrease the amp draw slightly
on
> > accessories. Some additional accessories like the Elec. cooling fans
and
> > TT's air compressor, amp, etc.. put a good demand on the batt. But
the
> > over-voltage should not present any problem on the B since there are
> really
> > no sensitive electronics onboard, except maybe the Hella headlights
which
> > are halogen and typically don't like anything above 13.5v. The MSD
should
> > not have any problems either. I have always been told that as a rule
of
> > thumb, a 10% increase of the rated voltage should provide a wide safety
> > margin. At 14v, we're running a bit more than that, but I do notice
the
> A/C
> > fan runs faster and therefore puts out a lot more air which is welcome
> here
> > in Miami. The OEM radio also plays cleaner which is a complete
mystery
> to
> > me. Time will tell if the slight increase in voltage is too much for
the
> > fan, but the extra boost in cooling is too much to not try and do it.
> >
> >
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