Another GM Alternator Conversion

bbrown said:
me the sense line on the Alternator. I've only seen 1 connection. :confuse2:
Click to expand...

Isn't the sense line the #2 connector, aka, exciter?

As for running 4ga from here, I only fully understand about 10% of what's happening in this entire thing. I don't know what the full potential of this wire should be. Plus I have plenty of 4ga wire laying around so I just used it.
 
Running 4Ga is great...

But what is this "exciter" contact you're referring to?
I always thought the X1/9 alternator is a 1 wire system.
But maybe this is for late models and not early models? I do remember an external regulator on very early models.
Rudy, can you take a photo of the wire(s) that come from your alternator?
 
OK, that model is a 3-wire alternator...

And I now see what you're talking about.

I think this site will help you with the hookup.
You can use a 14 gauge wire from the sense terminal (on the alternator) to the battery if you choose to go that way.
You can also tie it to the output lug if you wish, especially if you're using a 4GA wire to feed back to the battery from
the big terminal, (output lug) as you're not going to lose a whole lot using 4Ga to charge the battery.

Photo from Datton Tom:

alternator.jpg


Note the red wire... If this runs back to the battery, then the alternator will make up the wire loss difference.
The configuration shown above does not do that, and if you run 4Ga from the big lug to the battery, then this setup is fine.
The white wire should go to a bulb (indicator lamp) with the other side of the lamp hooked
to +12V to activate the charge field and indicate loss of charge.

Hope this helps! -Bob
 
Bob... My original Marelli...

as well as the Bosch I installed both connected via a stock "two-wire" plug.

One wire was a heavy brown wire going to the starter and the other a violet/black that leads to the dash lamp and is the exciter voltage.

In order to make the less expensive 3-wire GM alternator to work, it needs to be wired as shown with the "jumper" between the output lug and the #1 terminal. I'm pretty sure it has to do with REGULATION as the diodes internally would care for the RECTIFICATION.

As a side note... I have a 1-wire GM alternator on my T-Bucket and its neat and simple... with an Ammeter to remove the rest of the guess work. I'm sure it COULD be installed on an X1/9 but I see no advantage in doing so when the wiring and idiot light is already in place along with the voltmeter.
 
There are arguments for not doing the short wire

from the output post to the number 2 connection on a 3-wire GM alternator
http://bob_skelly.home.comcast.net/~bob_skelly/alternator_conversion/wiring_alternator1.html
But for the X 1/9 the argument is moot if you use the starter post battery connection point, since that point is already pretty far from the battery, especially on an old battery positive cable. It would be better to use a wire that had very little voltage drop according to this theory.
 
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