Generator cut out

D

David R.

Senior Member
Are these serviceable? I am in process of rebuilding my generator. I just got it disassembled and field coils out. Wondering if I should replace / repair cut out?
Whats with the diode thing? Someone recommended a voltage regulator replacement cut out?
 
The original ones work until they don't. They are just a relay. If it stops working the prevalent problem is the ground wire has become unsoldered.


Same with the ones with a diode, they too work until they don't but the difference is that the diode will need to be replaced. (easier to replace the whole thing).


The regulator "cutout" is made by fun projects and you MUST follow the instructions EXACTLY for it to work and continue to work as designed so that the generator will put out more as the car needs it.
 
I don’t have them (service bulletins). I have Les Andrews book, but not much there on generator and cut out. I haven’t tried to get cover off cut out yet. Just wondering if it is a serviceable component.
I was wondering also about which modern replacement cut outs if needed. Is a cut out something you would carry as spare parts on a driver?
If armature is ok generator should be straight forward. I will try to turn and undercut commutator and re-insulate fields.
Will these generators motor?
Last generators I worked on were on 50’s Fords and Jeeps.
Will I need to polarize? My first A (AA) experience. I have lots of questions.
 

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The cut-outs are serviceable. The original are pretty bullet-proof and the repro's are pretty much junk.

These generators will motor and since it has been taken apart it will need to be polarized.
 
Polarizing the generator field sets up a residual magnetism in the field shoes. It's this magnetic field that provides the power needed to open the cut out relay as soon as the generator is up to rpm so that the generator can come on line.

The old cut outs have some little spot welds to hold the can to the base. You can usually detect them with the cut out off the generator and turned up side down. They are just on the edge of the can and base there. Careful grinding is required to separate the can so that the cut out points and wiring can be inspected for condition.
 
I WOULDN'T DO THAT; Find someone that knows what the hell they're doing as the new ones are junk. Call Bert's and ask for Steve as he might just be able to help you with everything you need his number is 800-321-1931 there mt time.

They open on Tuesday to Saturday and when you are talking to Steve get a catalog, as his catalog has diagrams in the back of it that might just help you along.

But he will be able to help you more than anyone on here can and get a service bulletins book from him tell him you want the green one, and then ask him what book would be best for what you are trying to do.

Or he might just say send it in he can just might be able to test it for you and or fix it, but don't try that yourself. As I tried that and ended up buying a used one from Steve years ago.

Reggiedog
 
Resoldering a loose internal ground and sanding the points are about the only things that the average guy can do to service the cut out . Installing a diode would be better because a diode eliminates the points . The better choice would be the Fun Projects voltage regulator . Instead of being a cut off switch like the cut out , the Fun Projects voltage regulator gives voltage regulation that is similar to modern cars . Usually if the generator will motor it will charge . If the generator will motor but doesn't charge , the next step will be to repolorize . In some cases if the armature is good , the generator will charge . If the armature is magnetized it won't charge . I have a growler that I use to check my armatutres . In other cases the field coils will be bad . The field coils are more difficult to to remove and replace than the armature because of the slot head screws that hold the pole shoes in place . The field coils are just as likely to be bad as the armature .
 
Agree with Purdy on the Fun Projects voltage regulator. It looks like an original cutout and only allows the generator to charge as the battery needs it. It eliminates the issue of having to add water to an overcharged battery.
 
reggiedog said:
I WOULDN'T DO THAT

Reggiedog
Click to expand...

Wouldn’t do what?
I saw the little spot welds on my cut out cover. That’s why I hesitated trying to take it apart.
Yes the fields are difficult to get out. I had the same trouble on starter. Ended up heating screw heads with oxy/acet. torch and careful application of penetrating oil. Let the oil ‘fry’ in around the screw as they cool and they come right out. Starter field insulation was ‘leaky’. I gave them a fresh coat of insulating varnish and works great now. Here’s a picture of re-insulated starter fields.
 

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The attached article may help explain how the cut-out works.

I agree that the repos are junk. There is little or no tungsten on the contacts and they tend to weld shut. The diode modification works ok as long as you drive the car regularly. If you let it sit the reverse current flow through the diode will discharge the battery over time.

The best bet if you run a generator is to find an original cut-out that is still serviceable.

Tom Endy
 

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If the right type diodes are used, the units will hold back any reverse flow but they can crater out. The good ones usually go fully open so it doesn't hurt anything. If a person plans on driving the model A or AA a lot then the fun projects, or one made like it, is the way to go. It will protect from overcharge of the battery and even give a decent night time function as long as the 3rd brush is properly adjusted. They are sensitive to spikes and reverse polarity but they will last as long as a person has a good amp meter, a good battery, and takes care to listen when it's telling you something isn't right.
 
ryanheacox said:
http://www.funprojects.com/products/10505r.aspx


There is the link but they've been out of stock for quite a while now.



You might want to send Tom Wessenberg a message on this forum and ask if he has any regulators available. He makes a version that mounts inside the generator and replaces the 3rd brush. I have one and it works great.
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Yup, they work good. They need a cut-out though. [ meaning Tom's EVR]
 
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David;

I still think Bert's is the better way to go?, as they can help you more than you know just talk to Steve before you do anything on here. If you want to talk to Steve on here here's the way to do that, type in Steve 31B as that is how you can get a hold of him on here then you can ask him anything you want.

As he is very knowledgeable on stuff like this as he is the owner of Bert's as he might just be reading this already, but like I said talk to him before you do anything that there saying on here.

Reggiedog
 
Well I cut the little spot welds off with a file and opened up the cut out. Looks pretty good. Solder joints look sound. Took it apart, honed contacts with oil stone. Cleaned it up and adjusted point gap. A little corner broke off one of the little insulator cards under the points so to be safe I painted the area with insulation varnish.
 
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