Re: Automotive Circuit Protection - Part 1

[garwillis@msn.com (Garfield Willis)]

On Fri, 23 Jun 2000 14:39:23 -0400 Mike Rolica
<mrolica@meridian-mag.com>wrote:

>???? what is this for????  Get the newer gm alternator.....use a pwm
>regulator, upt to 400hz... :-)

You're not serious, I hope, with the "???s". Anyone wiring up circuits
needs to understand this topic better. Give ya just one example. When
you pick a +5V regulator chip to hang on the +BATT bus to run your DIY
circuits, you want to know what kinds of transient protection to look
for on the datasheet, that's built in or not. For example, there's a
world of difference between an LM7805 and an LM2931, and yet you still
see people using 7805s in DIY circuits. Not good. We're going to discuss
that in Part 2, sooooooo...

>I HEAR ANYMORE POWER QUAL STUFF, I'M GONNA PUKE!!

...don't puke, just nuke. You DO know how to use your delete key,
dontcha Mike? No way in hell this subject isn't "max on-topic".

>any way
> the EFI stuff.
>
>With new alt, truck runs great...charges at 15.5 v unlike 13.9 with old
>one...
>Also with scope on alt.. power is lots cleaner.. no more interference
>through stereo like old one :-)

Probly due to those newer ALT regulators chopping the field current at a
higher frequency; almost all automotive ALTs are still switching
regulators, hence the problems with noise. Interestingly enough, on
aircraft, the most popular for silent running use a LINEAR regulator
that continuously varies the field current, instead of just switching it
onNoff in bang-bang mode like most auto ALT regs. Harder to keep cool,
and more spendy, but valued in aircraft where radio noise is especially
problematic.

>But BLm down to 110 on way to work???? Were at 127-130 for last couple of
>months..
>Beginning to think ecm is quite picky on it's juice....
>Any thoughts?
>(remember, I was running a pre efi alt.....for carbed vehicle. Now running
>proper one..0)

I dunno, yous GMECM guys with lots of hysterical background (:) would
know bout that, tho I've never heard anyone suggest they were that
touchy. Sure would be pretty weak design if the ECU was a fussy eater of
ALT output/part no. I'd guess it were unlikely due to any change in
ALTs.

Gar


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