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From: jrm@cbuxc.UUCP (John Miller)
Newsgroups: net.auto.tech
Subject: conversion of 6 volt to 12 volt system
Message-ID: <362@cbuxc.UUCP>
Date: Mon, 11-Nov-85 09:19:55 EST
Article-I.D.: cbuxc.362
Posted: Mon Nov 11 09:19:55 1985
Date-Received: Tue, 12-Nov-85 04:27:21 EST
Distribution: net
Organization: AT&T Bell Laboratories - Columbus Comp. Center
Lines: 50

I have a 63 Ford model 4000 tractor. This is a full size agricultural
tractor. It has a standard starting system and ignition system, the
components are:

		6v generator
		6v starter
		voltage regulator
		6v ignition coil
		6v lights
		6v starting solinoid (external to starter)

The problem: The 6v starter system is crummy, it turns slowly and in the
winter will sometimes not start. I have jumped it with a 12volt battery
and found that the started (as expected) turns faster and the overall
starting interval is shorter.

The generator is not working, so I need to charge the battery periodically.
When the battery has a full charge then it starts reasonably well (but
still tough in the winter).

Since the generator is shot and the battery is 3+ years old, I am considering
converting to a 12 volt system. I would replace the generator and the 
regulator with a DELCO alternator (I would use one with a built in regulator),
the ignition coil, lights, solinoid, etc with the 12volt counterparts. However,
there is NO 12volt starter available - I must use the 6 volt starter. So the
questions are:

		1) can I use a straight 12 volts on this critter without
		   a premature meltdown (what would the voltage drop be,
		   etc.)

		2) should I try to rig a voltage eater in series with the
		   starter and battery:
			a) do they make a .048ohm/750watt resistor?

			b) is the an electronic way to do the same thing?
			   (e.g. SCR etc.)


		3) since the system is positive ground, can the case polarity
		   of the DELCO alternator be reversed or can the starter
		   be operated reverse polarity (since it is a D.C. motor
		   I would expect it to run the other way?)

Any help would be appreciated and yes I KNOW this is "net.AUTO.tech" not
"net.TRACTOR.tech", but I had hoped that someone out there might be
willing to tackle this problem anyway.


		j.r. miller, at&t bell labs, columbus, oh, us of a