Phil sez:
>Cory C. writes >
>> There's also an alternator *rely* that appears in the schematics, and
^^^^(Oops, did I actually say rely?)
>> which I *believe* I've located, next to the regulator, but the manual
>> doesn't give any troubleshooting information on it, or even describe its
>> function.
>
>Woodruff@caen.engin.umich.edu writes \
>
>\ Could this be used to prime the alternator on start-up?
>\(alternators don't have permanent magnets, so they need a priming
>\current to establish the magnetic field)
>
>I was stapling the padding on the cart holding up my Europa S2 body yesterday,
>when I noticed the little black plastic box above and slightly forward of the
>regulator mounted on the right inside fender. It looks just like the relays
>you get in air-horn kits.
Oh my God! Mine's below and behind the regulator... this could be
serious. (Not!!) `^)
>I figured it was another ridiculous add-on by the last owner but one (the
>Bonzai Electrical Engineer), but hearing that Cory's Europa S2 has one makes
>me think twice. No, I have not yet analyzed the map or tried to trace the
>mess he left me. The chassis work has dominated efforts so far, and all the
>wiring is attached to the body.
>
>Since these relays usually have a map of their internal parts molded into the
>case, and Cory has the map for the car, he should at least be able to
>determine that the thing is wired right. You can also check the voltage drop
>over the contacts to insure that the relay works, whatever the heck it is for.
It sounds like Phil's may not be the original relay (mine has "Made in
England" embossed on the bottom, so I'm pretty certain it's original.
(The other hint was all the rust and gunk on the inside... .)
This relay is old enough that the cover is held on by two little screws
and can be removed. Having done this, I noticed that the gap between
the contacts was about 1/8 of an inch. Also, when I energized the field
the contacts buzzed and bounced, aparently because the movable piece was
actually making contact with the field core (some AC noise might also be
making it through my battery charger -- it didn't occur to me to check
it at the time). After cleaning and adjustment, I got the relay to work
correctly on the bench, but when I put it back in the circuit, nothing
happened... still no charging. Whack on the regulator with a
screwdriver handle, and bingo! The Ammeter swung over to charge and the
engine RPMs dropped as the alternator kicked in.
What I've been able to figure out about this hare-brained arrangement is
this: The "alternator relay" is energized whenever the ignition is
turned on. All it does is complete the circuit between the regulator
and the positive side of the battery (although the relay is located
about two inches from the battery, the wiring routes clear around the
engine to connect to the hot lead on the starter -- why? Got me!). The
only reason I've been able to come up with to justify this system is
that perhaps it's designed to prevent discharge of the battery, except I
don't understand how the battery would be discharged if the relay wasn't
there... . It may also be there to cut the alternator off during
cranking in order to reduce the load on the starter -- I haven't checked
this out yet.
With an understanding of what's going on in the system, I can "hindsight
diagnose" my electrical troubles. I think the regulator is flaky, and
conspires with the relay to give me trouble. If the regulator decides
to switch off, I've sometimes been able to get it going again by either
turning off as many electrical loads as possible, or by whacking on the
regulator. However, this doesn't always work, especially when the
battery's low. Therefore, I think that the regulator would click off,
the battery would discharge, and the available juice wasn't enough to
keep the relay's contacts closed -- and bingo, there's no way to get it
working again, because even if the regulator decided to start working,
there wouldn't be a path through the relay to the battery. This would
also explain why the charging system would suddenly start working again
after the car had been sitting for an hour or so -- the charge in the
battery would rebound enough to keep the relay closed.
I'm now considering trying a solid-state system, in the form of a very
common Ford regulator that a parts-counter guy showed me: it has
terminals for Alt, Bat, Ign, and Gnd, if I'm remembering correctly, and
may replace both the relay and the mechanical regulator. My only
concerns about it are that the Ign connection does the same thing as the
relay (keeps the circuit between the regulator and the battery closed
while the ignition is on), and that the regulator section itself is
sized correctly for a 30-Amp alternator. Any hints from those who've
managed to wade this far through my ramblings would be deeply appreciated!
-coryc
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