The Stovebolt Site Forums The Shop Area The Electrical Bay Changing generator over to an alternator

Ok folks, I am sorry for asking this question that had been asked to death, I have searched other articles...............BUT, I am not completly clear on everything that is invloved with the change over from a generator to an alternator.

I am aware that the alternator has a built in voltage regulator and the one on the firewall is no longer needed. My 54 already has the 12 volt starter, coil and lights installed on it.

What I am confussed with is, what does the ammeter need to make it work correctly? Do I need a SHUNT? EXACTLY where do all these wires go that was once used on the regulator? I know that one wire goes to the battery (No brainer) and a couple that came from the generator, so these two I assume can be taken out and disgarded.

I've seen an article last night something about a BALLAST RESISTOR and then a VOLTAGE RESISTOR are they not, two of the same? I already know that I must have a resistor on the fuel gauge, to drop it down to 6 volts. I still have the instrument cluster out of the 60 school bus (another saga story in an earlier post) that I could use the ammeter out of, if need be. I have the alternator and the brackets to mount it on my engine from the old bus.

Please bare with my stupidity. I wasn't even going to change over to the alternator system, but the other night I had the headlights on and the heater on low speed the ammeter was really on the discharge side almost pegged sitting at a stop light and then running at normal town driving speed (30 MPH) it was still showing on the dishage side. I shut off the heater and it jumped on over to charge, to the first line on the plus side of the ammeter, I thinking it was at 15 amps or there abouts.

Is there an easy to follow schematic, that someone can point me to?

AGAIN, sorry for the dumb question, but you all have been so helpful with project. One just has to love this site.

John Niekamp

http://www.geocities.com/jniekamp/

Don't feel bad John, I'm in the same boat. Got an alternator but it's not a one wire type and I can't afford the kit to convert it so I need a schematic to show me exactly how to wire it up without frying something. Let me know if you find anything and I will do likewise.

Dave

I'm not sure why your ammeter is affected. You don't need to mess with shunts...current is current. The ammeter likely has a shunt built into it anyway because most meter movements handle only very small currents.

A ballast resistor is used in a points-type distributor, in-line with the voltage to it. A voltage dropping resistor may be used to lower the voltage to devices, usually to handle a change like a 6V to 12V conversion. I suppose technically you could call the ballast resistor a voltage dropping resistor but that is not how they are commonly referred to.

Wiring. Your generator has an output terminal and the alternator has one too. The output is usually the thickest wire. You probably have a generator warning light wire, that can simply be connected to the "1" terminal of your internally regulated alternator. This also provides the voltage necessary for the regulator/alternator to function properly. With the three-wire alternator, the "2" terminal needs to be connected to a 12V bus, i.e. where most if not of your electrical system draws from. It is this point that you want the alternator to regulate the voltage.

Do some research on earlier threads/topics. There is a wealth of information on this subject. You will also benefit by having a detailed wiring diagram for your vehicle to refer to. A good shop manual will have this information.

I think that I wired my one-wire alternator (12v in a '54 truck) as shown by this site:

http://mightymo.org/Proj_OneWire.html#Wire%20to%20vehicle

Tim

Thanks for ALL of the advice, guys.

Dave (knokeydv), I did find a web-site that gives the pros and cons of using a 3 wire over a 1 wire alternator. I alomost forgot all about the old 3 wire ones. Go here and you will find some real interesting points on why to have a 3 wire over a single wire altenator. I'm even second guessing my first thought now.
3 wire alternator

The Url that Tim (tclederman) listed was EXACTLY what I was looking for in a easy to follow shematic, but couldn't find myself for some reason. It's been bookmarked. The url that he listed also shows on how to convert a 3 wire alternator to a single wire alternator. Both of these are EXCELLENT sites. It's well worth your time reading them over. Thanks Tim.

John Niekamp

Thanks John! the URL's were really a big help!
Dave

P.S. I kinda like your truck the color it is. My shop is almost exactly the same color.
: )
Dave