Rebuilding a 6v Generator

[Zorba2.0]

I figured I'd take the time to document my try at rebuilding my generator and regulator off my 1300. The bearings gave way and started dragging but the whole thing needed cleaning up. There is a page on a 1967 website showing a little bit of tear down but he stopped when he could get the windings out. Anyway, pictures are worth more than words.

Fan side backing plate followed by the fan shroud plate

Bushing Orientation Couldn't get this off by hand. I had to use a bearing separator and puller from harbor freight.

These bolts go through the body and hold the bearing plates

With the bolts out, the rotor can come out... dirty

Brush side cap, springs are rusty but in good shape

This extra wire goes here

Orientation of the windings

I think Bosch deforms the screws from the inside so you cant remove them. I was able to drill through both sides amazingly straight and centered.

This paper has seen better days

Full of years and years of crud

Magic! Desoldered the two windings, removed the old paper and rewrapped using Tesa automative tape. Soldered the two back together and heat shrunk the connection just in case

Sand blasted and painted

Also sand blasted and painted

Reinstalled windings using M10x1.5-16 screws from McMaster P/N 91304A161
I also used blue loctite to prevent backing out.
I almost used Red but i didnt want to have to drill these out if I need to redo something.
If its not worth doing twice, why do it at all?

Re-enameled the windings on the rotor. Also purchased from mcmaster p/n 7437K19 "electrical insulating varnish"

I broke the fan side bearing plate by trying to use a three jaw puller before I bought the bearing separator/puller. Luckily only 1/3 broke and both of the mounting holes are on one piece so if I cant get them brazed together it should still work.

Next step is to clean up some of the smaller pieces and install the bearings

[viiking]

Before you go much further see if you can get the commutator back into the stator housing.

When I re-wrapped my windings with self amalgamating tape it was too thick and fouled the commutator. I ended up having to pull it all off again and use some thin masking tape. I could not get enough purchase on the bolts holding the plates in place to ever get the clearance needed with the self-amalgamating tape.

I'm not sure if you even actually need to wrap the windings or not. They should stay in place.

[mukluk]

[flyboy161]

This is why I love these forums so much. The ingenuity of some people is fantastic. It’s great to see peeps take on some of the more challenging tasks, like rebuilding generators. I look forward to the finale!
_________________
My father's 1970 Beetle-
http://www.thesamba.com/vw/forum/viewtopic.php?t=603879

The 1964...Diamond in the rough
http://www.thesamba.com/vw/forum/viewtopic.php?t=612776

My 1958 Morocco Bug-
http://www.thesamba.com/vw/forum/viewtopic.php?t=611483

[herbie1200]

I will check max tape working temperature.

Field winding can become very hot, often a "paper-like" tape is used, as in AC transformers.

Thank you for the interesting photos; I will bookmark them!

[Zorba2.0]

Thanks for the input. I’ll definitely check the tape max temp.
The windings are enameled wire so the won’t ground out to the housing, I think they are taped to keep them mostly together. If they weren’t enameled they wouldn’t create a magnetic field, they would shortcut the windings and go straight to the other side.

So far the total investment is under $30 for the bearings, spray varnish, and new screws. The paint I already had lying around.

[Zorba2.0]

I was able to silver solder the fan side end cap back together.

I reassembled everything with new bearings and brushes.

Now come the problems, I am still not able to polarize it. I used my multimeter to check continuity and I am getting connection between the brushes and the body, brushes and the rotor shaft, everywhere. The field windings are isolated. That is, until I connect the brush wire and field wire on the D+ side. Is this correct? I never traced continuity before I disassembled.

I’m going to tear it apart and poke around some more.

[panicman]

Thanks for doing this. I have been waiting for a tutorial on this very thing. Your success will be ours!!
_________________
Plate of shrimp

[Zorba2.0]

So after watching
https://www.youtube.com/watch?v=LAtPHANEfQo

Typically one brush and one field coil wire will be fed with the same wire DC source so I am good there, D+ and one brush are coupled.

I think I messed up by painting the whole thing. The brush that has continuity to the body NEEDS to ground through the strap to complete the connection. i'm only energizing one portion, the stator. The rotor also needs to complete connection so it can generate a magnetic field to move against.

I'm going to bench test this theory at work before trying to strip all the paint.

[Zorba2.0]

Alright, so the bench test went as expected nothing.

Took it home and discovered that the commutator is doing too much commutating - all 30 terminals have continuity to each other. Luckily they are isolated from the shaft. I couldn’t get anything to beep on the shaft to the windings. When running the multimeter across the insulation between copper strips it doesn’t beep. I though maybe there was enough carbon built up to cause everything to short, might still be the case elsewhere. If washing and scrubbing it doesn’t fix it, my next guess is the solder joints melted and smeared or something.

Does anything look out of place?

[hazetguy]

That armature is heavily worn and dirty. I would not think that it would be machinable and/or servicable. Even if you could have it cleaned up and it remained in spec (above min. diameter), any remaining service life will be short. Take the armature to a generator repair shop and see what they have to say. Personally, I would consider that to be scrap and I’d look for a better one.
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thebucket: I invested in hoodride, now DBD won't return my call?
hazetguy: invested?
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[kreemoweet]

[Zorba2.0]

I thought there is only supposed to be continuity between the terminals that are 180 degrees from each other? Why bother separating them at all?

[Zorba2.0]

"Each conducting segment of the commutator is insulated from adjacent segments. Mica was used on early machines and is still used on large machines" “Commutator (Electric).” Wikipedia, Wikimedia Foundation, 28 Feb. 2018, en.wikipedia.org/wiki/Commutator_(electric).

So yes, they should be insulated from each other. I'm gonna spray the crap out of it with the insulation paint and hope for the best

[mukluk]

Checking for continuity on a known good generator with the brushes retracted:
- segment to segment on the commutator: yes
- D+ to DF: yes
- D+ to gen body: no
- DF to gen body: no
- commutator to D+: no
- commutator to DF: no
- commutator to gen body: no

With the brushes in contact with the commutator, continuity can be found between any two points.
_________________
1960 Ragtop w/Semaphores "Inga"

[kreemoweet]

[Zorba2.0]

Ok, so that makes the water less muddy, or at least explains why I get continuity between them all.

What I should have done is test resistance and record all the readings to see if there is a burned wire or short per https://www.youtube.com/watch?v=lmjFzukDhqI

[cab57]

Hi,

for those who looking for exact countersunk bolt (N 010 999 1) for field coil you can find here :

https://www.volkswagen-classic-parts.de/en/senkschraube-b209f9.html

and you can use a drag link socket to tighten it:

On my side I would like to know the original color of wires connected to regulator and if someone know the kind of welding here: (it's seems that's is not tin.)

_________________
Beetle convertible built 06/66
Beetle ragtop built 28/04/59

[matthew henricks]

Is there any reason Kapton tape could not be used? I am measuring my old paper at .008". I can get paper at that thick but have access to Kapton as well.

Thanks

[viiking]