Generator rebuild issues

jax55

jax55

Senior Member
I have installed new field coils, brushes and leads, still does not charge.
I have a Nu Rex diode cut out that checks good (continuity one way only), I followed an exploded view of the Gen to hook up the leads.
The lead to the output terminal could not be soldered, so I used a ring terminal.
Also used a ring terminal for the ground lead from the field coils.
Terminal stack is as follows : terminal post, lead to field brush, insulator, tape on post to insulate ground lead from touching post and ground lead. post through insulator in field frame and nut/ washer on top of the insulator.
It motored in the wrong direction after rebuild, jumped across field terminal and output terminal. Motored in correct direction.. but very sluggish.
Armature checks out, no grounds or opens.
Any suggestions from the generator guru's?
I changed all this due to one of the original field coil leads breaking to the brush.
Worked one day, dead the next.
Thanks guys!!
 
The generator book(McRee) I have shows the test as using a 6v battery charger with positive lead to the case, and the negative to the terminal post. The generator should motor CLOCKWISE...

It further shows that if the generator motors BACKWARDS/COUNTERCLOCKWISE, then the field coil leads are installed backwards.....
 
Thanks "55". i guess based on that, it would be looking at the pulley for clockwise, and appear counter clockwise when it is installed looking from the comm end.
Unfortunately the "red book"'does not go into detail on rebuilding or troubleshooting.
 
I think normal motoring is if when powered it turns in the direction it normally is driven...
 
jax55 said:
I have installed new field coils, brushes and leads, still does not charge.
I have a Nu Rex diode cut out that checks good (continuity one way only), I followed an exploded view of the Gen to hook up the leads.
The lead to the output terminal could not be soldered, so I used a ring terminal.
Also used a ring terminal for the ground lead from the field coils.
Terminal stack is as follows : terminal post, lead to field brush, insulator, tape on post to insulate ground lead from touching post and ground lead. post through insulator in field frame and nut/ washer on top of the insulator.
It motored in the wrong direction after rebuild, jumped across field terminal and output terminal. Motored in correct direction.. but very sluggish.
Armature checks out, no grounds or opens.
Any suggestions from the generator guru's?
I changed all this due to one of the original field coil leads breaking to the brush.
Worked one day, dead the next.
Thanks guys!!
Click to expand...

The insulated non moveable brush from the commutator is the output brush and must go to the output stud. Correct this and see if it doesn't motor in the correct direction. Why can't it be soldered? The stud and wire can be carried to anyone with a soldering gun, if you don't have one. I would solder it and not use a ring terminal. The ring terminal from the field is pinched tight to the case by the output stud insulator, and is the field ground. The other end of the field goes to the adjustable brush.

Don't rely on tape to insulate anything on the output stud, because the pressure of the nut tightening will cut through the tape sooner or later. Only use the correct solid material for insulators.
 
Thanks all for your input.
Tom, I guess I am missing something here. I have all the new insulators for the output terminal, but I don't see how the ground lead off the field coil is kept from also grounding the brush/ terminal? I understand that tape is not ideal in this situation...there is not a lot of room to insulate the lead from the post.
I tried soldering to lead to the post, but I could not get anything to stick so went to the ring terminal.
I will give it another shot as I know that would be the ideal connection.
Thanks for the input and great information/ pictures!! It is very helpful amd I appreciate it as always.
I will follow up when I get it working.
 
I hope you have some of the good old rosin core 60/40 solder, because this new lead free solder is more crap being shoved down our throats.

The field ground terminal is against the case, then you should have an insulating terminal with a step to fit inside the case hole and insulate the ground ring from the output stud.
 
Tom, I have some 60/40 I just have to find it again. Moved recently and can't find everything yet. I guess my concern is how to ground the field lead without also grounding the terminal post. Just place the bare lead under the insulator and pinch it to the case?
Thanks for hanging in there with me!!
 
I have had this thing apart and back together too many times. I have solved the ground wire issue, soldered the lead to the post and looked at everything again.
I can get it to motor, but the wrong way, I have checked the field wire hook up and compared it to the old one too many times. They are correct! Are the field wored backwards? I doubt it, but maybe. It pulls too many amps when it does motor, close to 20. My next thought is that maybe one of the poles has punched a hole in the insulation and is going to ground, but that would not make it motor backwards. Right?
I hate to admit it, but I am stumped! Any ideas or suggestions are very welconme.
 
If it motors backwards then the fields are on the wrong sides.
You need to remove the two coils and turn them half way around.
Were you able to remove and tighten the field pole screws yourself, or did you have to take it to a shop?

Can you post a picture of the fields from the rear end of the case, to show the wire ends?
 
"I hope you have some of the good old rosin core 60/40 solder, because this new lead free solder is more crap being shoved down our throats."

Agree!

You said you have 60/40....rosin core? No acid or acid core for electrical work.
40/60 would be even better. The first number is the tin content.
The copper areas you want to solder must be very bright and shiny copper....sand'em nice and shiny
We use rosin core radio solder here for applications like this
 
TBird, rosin core for sure. Everything seems to be holding.
Tom, if this works I will attach a photo of the leads. I think what you said about he coils being 180 off is correct. I did get the old pole shoe screws out and back in myself. After moving them, they won't pull in as far and they hit the armature. Gotta love it!
Still working on it, but think you hit it on the head. You are the man.. Thanks!!
 
jax,
take one of the big screwdriver bits that has a 1/2" drive socket on the other side, the kind we use to adjust the end plugs on drag links and relay rods, and grind it down to fit the pole shoe screws.

Then place the gen (or same for a starter) in a large vise. Attach the screwdriver bit to your 1/2" breaker bar. Insert the bit into the slot in the screw, and set the breaker bar at 90° hanging out the vise. Tighten the vise. Now use the breaker bar to either tighten or loosen the pole shoes, all the while keeping tension on the vise jaws. This will keep the poles shoe screw slots from camming out, and allow a very decent tightening of the pole shoe screws. The pole shoes MUST be tight to the case. This is very easy to do with this method. You can also remove the most stubborn screws with this method. A thousand years ago when I worked in a carb/gen/starter shop we had a jig that provided just this type of action for us. You don't need the jig; you can set your vise up as described to do the same thing.
 
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Thanks Tbird, what a great solution to the pole shoe issue. I worked for a company that sold alternator/starter parts to rebuilders.. I should be able to figure this all out, I did most everything, but ended up in tech support at the end. I feel pretty dumb right now ;-))
We had a tool for the pole shoes, worked great.... I was wishing I had access to it today.
I will use your method and I am sure it will work WAY better than anything I have tried up until now. Thanks!!!
 
Before I had real tools for the screws I used a exhaust pipe expander with a sliced piece of pipe for a shim, and the "motorcycle screwdriver"---the hand impact you hit with a hammer to loosen and tighten the screws

harbor freight has large screwdriver bits that fit the screws well--it is a set of 4 or so, one fits as is, another fits better but the corners need ground some to fit the taper
 
jax55 said:
TBird, rosin core for sure. Everything seems to be holding.
Tom, if this works I will attach a photo of the leads. I think what you said about he coils being 180 off is correct. I did get the old pole shoe screws out and back in myself. After moving them, they won't pull in as far and they hit the armature. Gotta love it!
Still working on it, but think you hit it on the head. You are the man.. Thanks!!
Click to expand...


You have to put an expander inside the case to push against the field coils and force them tight against the case, then tighten up the screws.
 
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