Sam Goldwasser wrote:

Tim Wescott writes:


Sam Goldwasser wrote:


Another thing to note but which probably doesn't apply here is that if
some PM motors are disassembled without a "keeper" for the PM magnets,
it will become partially demagnetized. This isn't a problem with the
cheap PM motors you are probably using but may be with high quality
steppers or servo motors.
--- sam | Sci.Electronics.Repair FAQ Home Page:


I know that's an issue with AlNiCo magnets, and I know it's _not_ an
issue with Neodymium-Boron-Iron (temperature will kill those suckers,
but not demagnetization). Is it a problem with Samarium Cobalt or any
other modern high-performance magnet material?


The motors I'm referring to almost certainly used magnets more high
tech than AlNiCo but I don't know what it was. There must be some
info on PM motor maintenance from motor manufacturers on the Web that
would shed some light on this.

--- sam | Sci.Electronics.Repair FAQ Home Page: http://www.repairfaq.org/
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I was just curious if you knew.

Certainly a motor manufacturer could tell you this if they encouraged
maintenance on their motors. Many really small motors aren't designed
to be disassembled, however. Even the $150 precision motors from the
Swiss -- Escap and Maxon -- are pressed together and don't come apart
without fatally changing their characteristics.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com