Hi there,

I am trying to use a 10 S1 series Delcotron alternator, that is one of
several spares for my 1970 Corvette, collected when I had access to a
breakers yard. I have made all the mounting plates, pulley wiring
etc. to connect one to a diesel engine for a home generator. I have a
manual and lots of spares, but I just cannot get the thing to energise
and produce a charge for the battery.

There are several things that spring to mind. The engine is only
running at about 1000 rpm which according to the size of the belt
pullies, should be producing at least 2000 at the alternator. I have
connected the battery + directly to the main output and a link goes to
the no. 2 terminal on the regulator. The no. 1 terminal goes to the
+12v through a bulb and switch. The bulb does not go off at all.

Trying to short the earthy side of the slip ring to frame as suggested
by the book, by poking a screwdriver into the hole at the back of the
frame does not change the battery voltage at all. It is about 12.7
volts after starting the engine. This would seem to put the blame on
the rotor, the stator, the diode trio or the rectifier block, or some
thing else. As I have a lot of spare alternators of this type I have
been substituting varoius bits to try and find out why it will not
energise.

I have tested all the rectifier blocks, diodes, stators and rotors
with various meters and they all seem OK. I am sure the insultators
on the fixing screws are in the correct positions, all connections
vare clean, the resistance between two fixing screws on the brush
holder/regulator is about 40 ohms. But it will not go! The earth
cable goes to all the right places.

There must be something simple wrong that I am missing. I have had
this arrangement on many other US cars of that era and they all seemed
to charge OK on a fast tickover. Being on my own I must not be able
to see something. Has anyone got any ideas. Please.

Regards George.