Bob Flumere wrote:
>
> On Mon, 19 Feb 2007 12:43:05 -0600, > wrote:
>
> >
> >"Mike Romain" > wrote in message
> ng.com...
> >> The points 'do' arc out and burn in those regulators or you wouldn't
> >> need new ones.... I was always under the impression you needed the
> >> condenser to slow this down.
> >
> >You're right, Mike. The condensor is there to stop RFI but it does it by
> >stopping the sparking, which is an interrupted DC. Just like the condensor
> >used to do on points, it provides a low impedance path for high frequency
> >AC or interrupted DC.
> >
> >While an electromechanical regulator might not be a critical to spark damage
> >as ignition points were, the principle is similar.
> >
> To the OP.. you do NOT need this cap.....
> It is NOT a functional part of the charging system in any way...
> It is only a high frequency bypass to ground for radio noise
> suppression.
>
> Its purpose and connection into the circuit in this application does
> not affect nor control the arcing at the voltage control contacts...
>
> Having this cap in the circuit (or not) will not damage the regulator
> or affect the charging system in any way.
>
> The capacitor on the GM Delco voltage regulator is ONLY for RFI
> suppression.. it is not in the "Field" circuit where the altenator
> field (rotor) contacts are located.
>
> In the days of generator (as opposed to "alternator" charging systems,
> mis-connecting the RFI capacitor to the field terminal of the
> generator (an easy mistake to make in the day) would CAUSE a failure
> of the voltage control contacts in the regulator!!

Yes, I seem vaguely remember on a generator if you hooked a capacitor to
the field circuit it would actually make the contacts buzz louder.


> The cap in this particular application was mounted on the generator
> case, and designed to be connected to the generator "Armature"
> terminal which was in fact the current output terminal.
>
> GM DELCO used to put a big round red cardboard warning tag on the
> "field" terminal of the generators telling you NOT to connect the
> capacitor wire to this (field) terminal!
> In this instance, the capacitor was being used to suppress the RFI
> from the arcing at the generator brushes which would be heard as a
> "whine" on an AM radio..
>
> Of course these two connection terminals were located side by side on
> the generator case, and only a few of us could read the big red tag.
> So when this mistake was made the voltage regulator failure would
> occur within a couple hundred miles. <BG>
>
> These uses are NOT related to the use of a capacitor in "Point +
> Condenser ignition system, where the cap serves an entirely
> different function in the creation of the High Voltage spark and
> in fact does absorb the arc at the contacts that is created
> by the collapse of the field in the primary of the ignition coil on
> the "break" of the contacts.
>
> Again, I repeat, this capacitor on the Delco Altenator regulator base
> is NOT involved in the charging circuit in any way, and only exists to
> suppress the RFI generated by the arcing at the vr contacts...
> If you look at the back of the regulator base, you will see that the
> capacitor terminal is merely an extension of the "B" or Battery
> terminal lug. The capacitor from there to ground suppresses any
> HF RFI that might be generated from reaching the rest of the car's
> electrical system and thence being heard as a "popping" type of
> static on an AM radio..
>
> Feel free to ask for more technical explanation an any time.
> School is out fo now .. there will be a quiz later <G>

Hey Bob, Thanks for the info. Somewhere way back when, I think I used to
know all that. But now I think i've reached the point where I've
forgotten way more than I know.

-jim

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