6v Alternator
 

I converted a GM alternator to 6v positive ground with a kit. Installed it on my 29 Tudor. You have to rev the engine to excite it to charge. Is this common?

Re: 6v Alternator
 

That's the way mine works.

Re: 6v Alternator
 

Mine too, that's normal. You can rev it when you start up, or you can just let the car run off battery for the first few minutes until it kicks in on its own.

Re: 6v Alternator
 

ditto.

Re: 6v Alternator
 

Re: 6v Alternator
 

Thanks, I figured that was the case, just wanted other opinions. The alternator in my other Model A seems to have a lower cut-in point but that may be due to the little-bit smaller pulley.

Re: 6v Alternator
 

You can buy the smaller pulley from most Model A vendors and it will kick in quicker.

Re: 6v Alternator
 

I have the one available at the Model A parts dealers, but the one on my other alternator is even smaller.

Re: 6v Alternator
 

When you use the small diameter pulleys on an alternator, you will get better belt grip on the pulley, without a lot of belt tension, if you use a fan belt with the little V-notches in it on the inside surface.

Example:

https://s7d2.scene7.com/is/image/gat...v-belt-1-top-r

The exact belt you get will depend on the circumference you need for your engine setup. I don't want to quote a belt number and have it be wrong for your car. Work with your parts supplier.

.

Re: 6v Alternator
 

The alternator needs a small current flow through its field windings to start. The starting current in a modern car occurs when the charging light goes on as the car is started. I have an alternator in my Coupe that does not self start and requires revving the engine. To the contrary, I have a Nu Rex alternator in my Victoria that self starts. So there is a way of making your alternator self start, but I am not sure to do this.

Re: 6v Alternator
 

I know you can ground the #1 terminal on it momentarily and it will start charging.

Re: 6v Alternator
 

You can add an exciter wire to the 2wire plug-in, no.1 is excite term no.2 is voltage sense. Add a wire to no. 1 run into cab, by momentarily ground wire alt will start charging. Or you can add a resistor inside of alt to help turn on faster. There are several ways that will help.

Re: 6v Alternator
 

Re: 6v Alternator
 

And I thought it was notched for cooling !!
You ever consider writing a book -- for those's of less common sence, such as myself?


Example:

https://s7d2.scene7.com/is/image/gat...v-belt-1-top-r

The exact belt you get will depend on the circumference you need for your engine setup. I don't want to quote a belt number and have it be wrong for your car. Work with your parts supplier.

.[/QUOTE]

Re: 6v Alternator
 

I'm glad you find my little tips helpful.

I do not plan to write a book. I have been writing "Jim's Tech Tips" monthly for MAFCA for a couple of years now. They include it in a monthly email blast that they send to Members, and in another monthly blast to all of the Chapter newsletter editors, for clubs to put in their newsletters.

If you want to get the email blast each month, send your email address to modelagarth (at) yahoo (dot) com

.

Re: 6v Alternator
 

I went ahead and installed a momentary switch to ground on the #1 terminal. Now one touch and it is charging. Makes me feel better anyway.

Re: 6v Alternator
 

So on a similar note, what do you do about the self-exciting regulator that constantly has a parasitic draw on the battery?

Re: 6v Alternator
 

Yep, that would be your BX40 or slightly larger BX41. This is known as a cogged belt.

Re: 6v Alternator
 

Beats me!

Re: 6v Alternator
 

I use an isolating switch on the earth side of the battery. There can be no parasitic draw if the battery is not connected.