Dynamator Innards
follows
DynamatorWiring
This information is based upon the preliminary disassembly, by Jim Northrup,
of a Dynamator alternator from Accuspark that was purchased by Mort
Resnicoff and found to be faulty. Accuspark graciously replaced the
faulty unit with a new one that Mort has put to use in his 1950 TD.
I expect that this discovery process will be ongoing for a while, so
I'd suggest refreshing this page whenever you open it.
Jim is already familiar with the alternator (not from Accuspark,
nor labeled as Dynamator) having installed one in his wife's
supercharged TD (negative ground) a few years ago and it has run
thousands of miles problem free. I'm going to start this with Jim's text
created as he was "examining the critter".
First things first- I used a battery charger with VOM to verify
the current drain to heavy terminal D. (The battery charger
could supply measureable amperage without the fear of a
catastrophic short circuit if a battery were used.)
Then the back came off. A short shaft dropped out which made
me very happy so now I can remove the one out of our car and
open up the hole for the tachometer drive without extracting the whole
rotor. I was not impressed with the thin bushing with no
provisions for lubrication supporting only one end of that stub
shaft. Maybe I'll make an annual ritual of
pulling the tachometer drive and pack a dab of grease in the
drive and give the gear reduction a squirt at the same time.
The stub shaft engages the rotor via a slot without any sleeve
to maintain concentricity.
The next discovery was finding brushes. I'd hoped they'd be
brushless, but what the heck.
Then I was in for a pleasant surprise to see what is very
similar to a Bosch brush holder/voltage regulator. I have
wished that every alternator could be so easy to swap
brushes & regulator. Nice to know a good quality solid state regulator
can replace it economically. There are wires soldered to Dynamator's regulator and it is mounted internally, but it
is a helluva lot better than the rumors the first generation
had a garden tractor regulator. This one has a silver
plated "can" package for the solid state regulator whereas
ours has a black painted one with different markings
visible. I happen to have four Mercedes 300SDs along with a
spare engine from the early eighties.
It only took about 5 minutes to reassemble all those
pieces. The funny thing is, after slapping it back
together, it doesn't have that parasitic drain! While
dissecting the electrics, I noticed a wire jammed
against frame parts or something. I bent it up and
checked to see if the insulation was compromised but it
didn't look bad. Probably had nothing to do with the
trickle but an accidental win is still a win.
Okay, that's what a knowledgeable sort had running
through his mind as he made a first acquaintance with a
Dynamator. I find it quite interesting to note
that Jim's initial 'r&r' caused the abortive drain to
disappear.
Now, let's see some images of further examination of what's inside the case
starting with
Innards1.