Re: [CAD_CAM_EDM_DRO] Jan....opening steppers can......

In a message dated 27-May-02 19:24:50 Central Daylight Time, asdf@...
writes:

> You say opening up a stepper can trash them, does it de-magnetize them?
>
>

RC: the "factories" have fixtures that permit sliding the armature (toothed
magnetic thing" down into the stator (internal-toothed coil-thing) and
housing, inserting the "front" bearing, so that the two parts never touch.
Then, the "rear cap" is pushed on, and screws are installed. This way, the
"teeth" never touch.

I do not think the "problem" is so much the demagnetization (which may-well
be a factor--I just don't know!), but the "magnetic stuff" (Alnico, in most
cases) is as brittle as hard candy, and it "chips off", and these chips can
"jamb" in the concentric space between the stator and rotor (armature), and
[deleted]-up the smooth rotation of it.

I had a situation, once, where I HAD to do this "horrible thing", and I
remember LOTS of "magnet crumbs" had to be cleaned off the parts before I
re-assembled, and, WHEW! All was good! But I have been told by "stepper
makers" that I was simply very, very lucky! (I had a new motor - over $200!
- on hand, just in case! It is my "spare", now!) Jan Rowland


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