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RE: Alternator Conversion TR3

To: "Pete Thatcher" <pthatch@pacbell.net>,
Subject: RE: Alternator Conversion TR3
From: "Randall" <tr3driver@comcast.net>
Date: Tue, 16 Aug 2005 15:54:45 -0700
>  The batt. connector on the alt. is easy enough.
>  I was going to replace with a heavier gauge and terminate on lug
> D of the VR.

That won't be right, unless you've gutted and rewired the insides of the
original control box.  One of the functions the control box provides is to
disconnect the generator (D terminal) from the battery when the engine is
not running.  However the alternator does not need this function, and the
contacts inside the control box won't handle the current.

I would suggest going to the 'A' terminal instead.   I ran that way for many
years, but the link between A and A1 inside the control box eventually
opened up, so I removed it and wired them together directly.

Note that you'll also be overpowering the ammeter to some extent, so I would
suggest adding a shunt across the back of the ammeter to reduce it's
indication.

> The "R" or 1 connector of the alt. is for the idiot
> light and I don't know what to do with it.

Why not hook it up to the idiot light ?  The IGN lamp on the dash is already
wired to the D terminal on the control box.  If you remove the ground lead
(E terminal), you can simply connect the wire from terminal 1 on the
alternator to the D terminal.

You may also find that you have to rev the engine way up to get the warning
light to go out (and the alternator to start working).  If this is the case,
you may want to add a resistor across the dash lamp.  ISTR my Chevy had a 10
ohm resistor here, but I don't have the reference handy to check.  Most
likely it's not needed.

It's the current through the warning light (and the resistor if present)
that initially excites the alternator when you first start the engine.  Once
the alternator generates enough voltage to overcome the diode drop, it
becomes self-exciting.  Then the current through the light drops to zero and
the light goes out.

>  The "F" or 2
> connector of the alt. is used to excite the alternator and looks
> like I can hook that up to any 12v source or even just jumper it
> to the batt. connection on the alternator.

You'll get better charging performance if it is connected closer to the
battery, like to the hot terminal (brown wire) on the starter solenoid.
It's not to excite the alternator, but rather allows the regulator inside
the alternator to sense the battery voltage without 'seeing' the voltage
drop in the wires caused by the charging current.  Not a big deal, it will
still work fine with it just jumpered to the output, but that's why GM put
the terminal there.

Randall




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