Electrical: Generator question for the old school guys

[Okiejoe86]

Whats up?!

I just finished the rewire on my 1940 President. Everything is working perfectly except for the ammeter. Before the rewire, that gauge would move along with the amount of throttle i gave it. Bouncing between 10-35amps. Now after the rework, it is staying steady around 10 while driving. I dont know to much about these old school charging systems, but is it possible i have a wire mixed up somewhere? While it was running, I unhooked a battery cable (Mindset is that on alternator equipped vehicles, the vehicle runs on the alternator) and the engine died. Signs of a faulty generator?

Any insight would be appreciated!! Thanks!!

-Joe

[41 Frank]

Might have to polarize the generator. Since the engine died when the battery was disconnected that would indicate it is not charging.

[Okiejoe86]

Might have to polarize the generator. Since the engine died when the battery was disconnected that would indicate it is not charging.

That is what I was thinking. I know that on Alternator equipped vehicles you can unhook the battery and the engine would stay running. Reason being is that vehicles run off the alternator and the batteries soul purpose it for starting reasons. I wasn't sure if the Generator played the same role or not. I have not touched a generator in a loooong time. Time to do a little more research on generators. Thanks for your input!!

[41 Frank]

Actually a vehicle equipped with alternator should stop running when the battery is disconnected because unlike a generator an alternator needs current input to achieve output.

That is what I was thinking. I know that on Alternator equipped vehicles you can unhook the battery and the engine would stay running. Reason being is that vehicles run off the alternator and the batteries soul purpose it for starting reasons. I wasn't sure if the Generator played the same role or not. I have not touched a generator in a loooong time. Time to do a little more research on generators. Thanks for your input!!

[Okiejoe86]

Actually a vehicle equipped with alternator should stop running when the battery is disconnected because unlike a generator an alternator needs current input to achieve output.

Incorrect. An alternator uses an armature spinning inside stator windings producing a magnetic field that induces a voltage. In doing so it produces electricity for the vehicle while maintaining the battery.
It turns mechanical energy (The belt driven by the motor) into electrical energy ( Armature inside the stator)

[Okiejoe86]

Incorrect. An alternator uses an armature spinning inside stator windings producing a magnetic field that induces a voltage. In doing so it produces electricity for the vehicle while maintaining the battery.
It turns mechanical energy (The belt driven by the motor) into electrical energy ( Armature inside the stator)

Edit.... The more I thought about... you were correct. hahah my bad. But a car will run with the battery unhooked

[rstrasser]

Okiejoe86;
I have no idea as to what you did when you rewired the car. In any case before you rewired the car it was not normal for the ammeter to continuously jump between 10 and 35 amps charging. If there are no shorts in the wiring the ammeter needle should show a steady rate of charge If it does not the regulator is not doing its job.
Nor is a steady 10 amp charging rate normal.

The purpose of the ammeter is to show the current going into (charging) and out (discharging) of the battery. If the battery is fully charged and if the generator is putting out enough current to handle the cars electric draw then the ammeter should stay around 0. Neither charging the battery or showing the battery being discharged. The less movement of the ammeter needle the better job the regulator is doing. The advantage of an electronic regulator.

The main advantage of a alternator over a generator is that the alternator puts out more current at slow speeds. As for if the car should be able to run without the battery. I would say a Studebaker; if the car was first started and then the battery was disconnected the car should keep running. Not sure about all the different generator and alternator connections that there are.
A few years ago I had the battery in my Bronco fail at Newark Airport; after driving there to pick up my son. Jumped the battery with another car and the car would keep running as long as I turned off the head lights and all other electric loads when the engine was idling. Made stoping at toll booths fun.
A generator is polarized in order to magnetize the field coils. If there is no residual magnetism in the field coils the generator will not start generating and the cut out relay (part of the regulator) will not pull connecting the armature terminal of the regulator to the battery.
Ron

[jclary]

Edit.... The more I thought about... you were correct. hahah my bad. But a car will run with the battery unhooked

Well...again, commenting above my "pay-grade"...but somewhere in my ancient past, I recall something about Parallel and series circuitry. For example, your headlights are parallel wired. That means, if one of your headlight bulbs burn out, the other will stay lit. If they were wired in series, then if one failed, the other would too. I believe that is the same for charging circuits. If the components in your charging circuit are wired in series, all must be connected/working for the vehicle to keep running. If they are set up and regulated Parallel, then theoretically, if the alternator/generator fails, the vehicle will continue to operate until the battery runs down. If the battery fails, with a parallel charging circuit, the vehicle will continue to operate until it is cut off. Again, I could be wrong, but I think I have had vehicles with both types of charging circuits. Some would operate without the battery connected and others not. I have no proof, just think I have experienced both situations. And...I ain't gonna go out and start messing with my "fleet" to make sure.

[Okiejoe86]

It is possible that I may have a few wires swapped at the generator and regulator. Here is a picture of my connections.

Also, Is is possible to wire the ammeter gauge backwards and it will read backwards or not read at all??

Thankyou for the input everyone!

[Okiejoe86]

Well...again, commenting above my "pay-grade"...but somewhere in my ancient past, I recall something about Parallel and series circuitry. For example, your headlights are parallel wired. That means, if one of your headlight bulbs burn out, the other will stay lit. If they were wired in series, then if one failed, the other would too. I believe that is the same for charging circuits. If the components in your charging circuit are wired in series, all must be connected/working for the vehicle to keep running. If they are set up and regulated Parallel, then theoretically, if the alternator/generator fails, the vehicle will continue to operate until the battery runs down. If the battery fails, with a parallel charging circuit, the vehicle will continue to operate until it is cut off. Again, I could be wrong, but I think I have had vehicles with both types of charging circuits. Some would operate without the battery connected and others not. I have no proof, just think I have experienced both situations. And...I ain't gonna go out and start messing with my "fleet" to make sure.

You are correct about parallel and series circuits. example: old x-mas lights. one goes out and need to check them all. newer ones, one light goes out, you see it and replace it. I have no knowledge about charging circuits being wired in parallel or series. Interesting theory though.... hmmm... gears in my head are now rotating!! HaHa thanks for the input!!

[Okiejoe86]

YEAH! I have hit a milestone and hit 100 posts!!!!!! ..random note

[Skip Lackie]

It is possible that I may have a few wires swapped at the generator and regulator. Here is a picture of my connections.

Also, Is is possible to wire the ammeter gauge backwards and it will read backwards or not read at all??

Thankyou for the input everyone!

[ATTACH=CONFIG]53046[/ATTACH][ATTACH=CONFIG]53047[/ATTACH]

Ammeters don't care which way the current goes. If you wire it up backwards, it will just show discharge when it the generator is charging.

[Okiejoe86]

Ammeters don't care which way the current goes. If you wire it up backwards, it will just show discharge when it the generator is charging.

Thanks for the input!

[rstrasser]

The picture that I have of a Delco regulator shows the terminals as follows. Left most terminal goes to the battery. The center terminal that is right of center goes to the Armature terminal of the generator and the right most terminal goes to the field terminal on the generator. I am unable to make out any marking on the generator as to which is the field or armature terminal. Nor do I know what would happen if you reversed the field and armature terminals. Never tried it. If anyone has, let us all know what happens then we can all learn.
Ron

[greyben]

The most likely result of reversing field and armature wires is destruction of the regulator.
The generator is disconnected from the battery via the cutout relay in the regulator. This may occur at idling.
The ammeter may read consistently high if an electrical load is not wired through the ammeter. A bad cell in the battery may also require a greater current.
A bouncy ammeter is an indication the regulator is not perfect. It may continue to function for a long time though.
Most of the electrical problems on the forum turn out to be poor or misplaced connections. You mention that you just rewired the vehicle?