• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

TR2/3/3A Wiper motor armature

Share this page

N

NatS

Freshman Member
Offline
AE322397-109A-4F9D-B1D7-FBEAA63EBA56.jpg39DB463F-DEEF-4D4C-8689-BA0D26435680.jpegI disassembled my wiper motor to clean and refurbish. As I was cleaning the armature I noticed these little bits of fiberboard were falling out from under the windings. Most of them are still tightly embedded under the windings but I don’t want them to come out after I reassemble the motor. Any advice on how to get them to stay in place?
 
Last edited:
The classic material was varnish, but I'd probably use JB Weld or similar.

From the looks of it, that armature has been overheated pretty badly, which is why the fiberboard pieces are breaking.
 
would i epoxy the pieces back under the windings? i can add a dab to each piece.

I could also cut a new piece if necessary from some fibreboard or gasket material
 
Looks like it is well done if not a little over done.

The insulation on the windings may be compromised.

David
 
Right. If you have the option, it might be better to look for one in better condition. If not, at least double-check that there is no continuity between the commutator and the shaft (which would indicate a shorted winding). Ideally, the armature would be checked on a "growler", but I have no idea where you would find one today. (I bought an old one on eBay, but it will need to be refurbished before I can use it, and I'm quarantined 2000 miles away. )

And the less you can disturb those windings, the better. So I would probably try to glue the old pieces back, as many as you can find. They are just cushions really, to help keep the edge of the lamination from cutting through the enamel on the wires; not otherwise important to operation.

Try to work a little epoxy under the ones that aren't broken, too. Might help keep them from breaking in the future.
 
If you were closer, I'd lone you my 100 year old growler to test the armature before putting any effort into it. I would not worry about the cardboard. If they are loose, pull them out, otherwise leave them alone. They were there to keep the coils off the metal while it was being wrapped. Now the wires have taken a set, so they don't need the cardboard.
 
Is a Growler the same as a hand cranked Megohmmeter?

A friend used one to"FIX" his phone line after multiple calls to the local phone company who said the line was fine. He always had noise and static on the line. So he waited for a big thunder storm and blasted the line. He had no further noise issues on the line.

David
[h=1][/h]
 
Not the same. A growler is specifically for testing armatures, by applying a strong AC magnetic field to the armature. If a winding has an internal short, current flows through the short, which can be detected by laying a strip of metal (like a hacksaw blade) on top of the armature. If a short is present, the metal vibrates or "growls", hence the name.
https://en.wikipedia.org/wiki/Growler_(electrical_device)

Fancy ones may have other features; the one I bought has a meter to measure the induced voltage across commutator segments and also a simple continuity tester (a light bulb running on 110ac!).
sXctzYP.jpg


It could be that someone made a growler and a megger (megohmmeter) in the same box, but I've never seen one.
 
As a slot car ex-pert I can say an armature only needed the padding for original winding. I would rewind Revel motors with larger wire and fewer turns then coat the wire with a layer of epoxy just shy of the OD of the metal of the poles and ballance on a fixture made of single edge razor blades, drilling material off the bottom when the spinning stoped. W/O the epoxy the motor would tear itsself apart in the first few seconds of operation.
yUnless you plan on a lot of driving in weather I would remove all tou can and epoxy the rest to prevent debris in your bearings.
 
Yep, Randall put me onto growlers 10 years ago. Coolest tool ever. When I bought my "$100 pile" of Triumph parts it came with about 8 starters and generators. The growler quickly sorted out the bad ones that were not worth messing with...and gave me the best armatures that are still running in my TR2. Such a simple tool it's amazing.
 
Now you are getting into my field. 30 years with TVA rebuilding generators. You can dip the armature into varnish up to the bottom of commutator, let it drip and then bake it out in an oven at 250 for four/five hours. Or you can buy a can of glytal insulating paint. Spray the winding, soak them with the paint and it dry. That should lock everything in and reinsulate the windings.
 
Back
Top