Re: [CAD_CAM_EDM_DRO] Replacing bearings in stepper motor

In a message dated 10/22/2002 10:27:58 PM Central Standard Time,
echnidna@... writes:

> Are there any hazards replacing bearing in a stepper motor?
>
>

Bob: Yes. I have DONE this, and it takes AT LEAST "care".

First, the rotor is a multi-poled magnet, and looks like two or four "thick
pinion gears". It is alnico, and very brittle, so if those "gear teeth" rub
on the like-teeth of the stator (which has the windings), it will "chip off"
small particles that will JAMB the thing, when you re-assemble it! So, this
is why they will NOT warrant a stepper that has been dissassembled "outside
the factory" (they have jigs to hold all the parts concentric for assy.).

The bearings I had in the one I had to re-do were NOT sealed nor
"life-lubricated"! They were "shielded, only", and got FULL of dust, so
"froze up". Use DOUBLE-SEALED, Lubricated for life type bearings! Be VERY
careful when you pull 'em off the shaft, and be SURE you push ONLY on the
inner-race to install the new ones (i.e., don't transmit the "pushing force"
through the balls!)

Check the solder-connections to the lead-wires "while you're in there", as
the ones on my NICE, new S.E. motor looked as if they had been done by
dexterity-challenged children!

Lotsa luck! Jan Rowland


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