Generator assembly question

[Bruce B.]

I have a 57 Corvette generator that was taken apart, chromed and stored for 40 years.
While trying to assemble it I found that the armature rubs on the fields.
There is virtually no chrome on the inside of the case so that is not causing the interference.
I have tightened the screws that hold the pads in but I still have interference.
Any suggestions on how to resolve this problem?
Thanks,
Bruce B

[Joe L.]

Re: Generator assembly question

I have a 57 Corvette generator that was taken apart, chromed and stored for 40 years.
While trying to assemble it I found that the armature rubs on the fields.
There is virtually no chrome on the inside of the case so that is not causing the interference.
I have tightened the screws that hold the pads in but I still have interference.
Any suggestions on how to resolve this problem?
Thanks,
Bruce B

Bruce-------


Do you know that the armature and rotor are original to the generator and the correct parts? Can you find any identifying numbers on the two parts? It might be unusual for there to be complete GM part numbers but there might be a 3 digit derivative.

[Richard M.]

Re: Generator assembly question

Bruce, There should be small (maybe 1/8" diameter) alignment pins in the ends of the end frames and case. These align with notches in the case or frame. Are the pins there? If the endplates are not aligned to the case, this may be causing the problem. Sometimes when tightening the 2 long bolts it takes a little twisting adjustment to get armature to field clearance.

A few reference photos....

Notch on the end mates with pin on the end frame


Pin on the case end mates with notch on the end frame




Rich

[Bruce B.]

Re: Generator assembly question

Joe & Rich.
The part number stamped on the armature is 192964 ending with a C or a 0.
The fields (shoe and coils) are original but I do not see any numbers on them.
The problem is when the armature is inserted it rubs on the field shoes at one fan end and does not slide in completely.
All parts are original and appear to be in great condition and the case has been chromed. There is a bit of chrome flash on the interior but my plater said it should have no dimensional affect on the assembly.
It appears that if I can remove a few thousands from the iron shoes it would allow the armature to fit.
Any suggestions on how to do it. Our last starter generator repair shop has closed recently.
Bruce B

[Joe L.]

Re: Generator assembly question

Joe & Rich.
The part number stamped on the armature is 192964 ending with a C or a 0.
The fields (shoe and coils) are original but I do not see any numbers on them.
The problem is when the armature is inserted it rubs on the field shoes at one fan end and does not slide in completely.
All parts are original and appear to be in great condition and the case has been chromed. There is a bit of chrome flash on the interior but my plater said it should have no dimensional affect on the assembly.
It appears that if I can remove a few thousands from the iron shoes it would allow the armature to fit.
Any suggestions on how to do it. Our last starter generator repair shop has closed recently.
Bruce B

Bruce------


I can't find that part number but original part numbers could very well have been different than SERVICE part numbers or the number you found could just be the part number for a component of the finished armature assembly. In any event, there were, apparently, 3 different armature assemblies used for different part-numbered 1957 generators. They can be identified by differences in length.

[Richard M.]

Re: Generator assembly question

Bruce, Is this a Tach Drive Generator?

[Bruce B.]

Re: Generator assembly question

Rich & Joe,
I was just going to state that this indeed a tach drive generator and it was original to the 57 # 48??
The total length of the armature is 11.25" measured with a good scale(I need a 12" caliper).
Bruce

[Joe L.]

Re: Generator assembly question

Rich & Joe,
I was just going to state that this indeed a tach drive generator and it was original to the 57 # 48??
The total length of the armature is 11.25" measured with a good scale(I need a 12" caliper).
Bruce

Bruce------


OK, I did find it. It's GM #1929640. It was used with generators GM #1102020, 1102025, 1102041, and 1102043. It was used with only 1 field coil assembly of GM #1922701.

The 1929640 is supposed to be 11-5/16" overall length.

[Richard M.]

Re: Generator assembly question

I think the armature stamped part# should be 1940313. I've rebuilt many tach drive generators and that's the number I typically see.

My P&A data for it shows 11 5/16" OAL, but I'm now thinking it may be a smaller diameter than what your 1929640 is. Unfortunately, I don't have one here to measure. If you can get a measurement of the diameter of the 1929640 it may help. Maybe you could give John Pirkle Jr. a call and ask if he could measure the OD of a 1940313 for you. He probably has a loose one lying around.

Rich

edit.....I now see that in January 1959 the 1929640 was superceded to the 1940313......so now I'm uncertain.

[Bruce B.]

Re: Generator assembly question

Guys,
Thanks for all the info.
I will take some measurements of the armature when things calm down.
Then I do the same on the other tach drive generator which is on the 57 Gasser.
If the other armature is smaller I will try it in the chrome case.
This sounds like a winter project, it is time to drive.
Bruce B

[Richard M.]

Re: Generator assembly question

Bruce, not sure if you saw my edited post just above, but those 2 armatures should be identical as the latter was a superceded part. Shou;d be identical dimensions. IMO.

The only other thing to check is if the field plates are slightly twisted. Maybe loosen and retighten them next time you're in there and see if that helps.

Rich