Re: [CAD_CAM_EDM_DRO] Question to Mariss about demagnetion was Re: Torque when usin

Bob,

This has been discussed many times on the list, and one of the opinions that
came up was, once you remove either endcap, there is nothing supporting the
rotor, which will be pulled sideways onto the magnet, chipping pieces off in
the process. The little pieces will be impossible to remove with the rotor
still in the motor and difficult to do with it removed. They will then cause
the motor to jam up as the pieces wedge between the magnets and rotor. The
magnets are very brittle, and they use special jigs at the factory to keep
that from happening.

That said, if you have a motor with bad bearings, and it's no good as it is,
give it a try. What have you got to lose. I once had a PacSci Nema 34 motor
with a bent shaft, I took the rotor out, whacked the bent shaft with a
hammer about 100 times until I got it fairly straight, and put it all back
together. Seemed to work ok for me after it went back together. I was going
to toss it away anyhow, so I gave it a try. It may have lost some torque in
the process I suppose, but I used that motor until I upgraded to servos.

Bill

ps For sale, 1 PacSci Nema 34 stepper motor with a slightly bent shaft :)

> Thanks for your very helpful comments Mariss.
> I dont see major mechanical problem dismantling a stepper without removing

the rotor. The small ballraces used won't need heaps of pressure to slip
them off a shaft.

>
> Its really just a matter of making a simple puller and a simple clamp

system that will allow an end housing to be slipped off a shaft without
displacing the rotor.

>
> I agree making up loose pole pieces to slip the rotor into to maintain a

magnetic circuit would be an engineering exercize not worth considering.

>
> In the US its certainly worthwhile just getting new motors rather than

mess around but here in Australia steppers are not cheap or easy to find and
international mail at about $25 or far worse Fedex at about $95 for goodies
about 6lb weight can mean ebay might be impractical sometimes. (especially
if the vendor dislikes mail)

>
> Again, thank you Mariss, forwarned is forearmed.
>
> Bob
>