WTD: Armature for a Servo 140?

[Marty_Escarcega]

I have a Servo 140 that was given to me. There is a "flat" spot on the armature. I polished the commutator and cleaned the brushes. It worked great for about 30 seconds. It will stop on the "dead" spot and won't run again unless I turn the motor past the bad spot. Anyone have a good armature they want to part with or know whether or not this one might be repairable? Can't help but wonder what Servo would want for the Armature....

Thanks guys,
Marty

[rkepler]

If you do need a replacement (instead of finding the bad winding and fixing it, something a decent motor shop should be able to do) let me know and I'll look up the folks who fixed mine. I've got a couple on the Lagun and after one had the smoke let out a few times (and I repaired it each time) I finally sent it off for a rebuild. I think it's been 6-7 years now with no problems...

[Marty_Escarcega]

Thanks Russ. I'll try and find a motor shop to take a look at it. If I don't have luck I'll get back with you. Thanks!
Marty

[fredwhite]

There is a private factoru authorized repair shop in St. Louis as I recall. Years ago I bought some used parts from him. Nice person. Let me know if you want me to try to find the address. However, first check with the company and see if there is a factory authorized repair center closer to you.

[generic]

I have several servo cases (with motors, if good). Just dont know if they are still available.
They are part of things left at 'sold' property. The new owner has 'so far' not been bothered by me visiting and picking up things I allegedly forgot to haul away. I'm planning on visiting again within the next two days. 'If' they are still available I'll try to grab them.

[Doug_C]

How much of a flat spot is it Marty?

First, could it be caused by a bent shaft? When the gears get stripped out of these drives there is a lot of force to them instantly. Could have been before you got it after the gear was replaced it failed?

You could turn up a true center point in your chuck or collet and then turn that commutator between centers to skim some off the contact area. Use a HSS cutter with a nice honed radius and positive rake. It should come out perfect.

Then clean up the burrs and chips well with a razor so that no shorts exist between the poles. I would imagine .020 would be the maximum diameter reduction allowed. If it is much beyond that, it is probably scrap.

Secondary to that, I would check to see how the brush length is. If there is not enough travel it will not follow the surface. Not that is should be that far out of round.

A note of caution, if you see any arcing between the commutator poles, it may have a shorted winding to begin with . My suspicion is, that is often where flat spots come from. Tell-Tale signs are black arcing marks in one location.

DC

[Dave_V]

Marty,

A friend bought one ( armature for a 140 ) direct from Servo for $ 87.50 less than 2 years ago. I have also bought the large gear from a local dealer and I found that the delivered cost was within pennies either way !

Good luck,

Dave

[Marty_Escarcega]

Yes "Generic" if they are available please do grab them. I appreciate it.
Marty

[Marty_Escarcega]

I think mine is shorted. It won't run unless I turn it a touch. I found new armatures thanks to a link someone provided for about $125. IF that's all that's wrong with it, I would think its cost effective to repair. Though I was hoping for a parts unit...just in case.
Marty

[Marty_Escarcega]

Thanks Dave_V. Probably a call to Servo may be in order if I can't find a parts unit to salvage the armature from first. The guy that I was referred to on the web may be marking up the cost to make some money.

Marty