Re: Info from Ah-ha! on BOSS's/Motors/HVdrivers

--- In CAD_CAM_EDM_DRO@y..., JanRwl@A... wrote:

> If the motor you "remove the end-cap" on has the bearing IN the

end-cap, as all I have ever seen do, the armature (toothy magnet) WILL
bang into the stator (toothy inside-gear thing), and chips of ALNICO,
etc., WILL break off and cause jamming, at least reduced function, and
will cause need of investing in Tylenol, etc.

>
> Without the "factory jigs" to hold the shaft and body

"axially-parallel", NEVER take off the end-cap of a stepper! If it
worked for you ONCE or twice, NEVER assume it will "often work for
you", as that IMPORTANT motor will be > the one you mess-up! That is
Murphy's Stepper Motor Corollary.

>
> Jan Rowland, Troll

howdy Jan,

I'm sorry you had bad luck with your 8-wire conversion.

I've converted probably 50-60 motors over the past
10 years, and I have not had a single one damaged
in the way that you describe. Perhaps I've just
been lucky. Or perhaps your problem was caused by
an -external- particle which found it's way into
the motor while you had it apart.

All of the step motors that I've worked on, and all
the hybrid motors that I'm aware of, have a VERY tiny
rotor-to-stator gap....typically only .001" or even
.0005". There simply isn't enough -distance- in these
motors for any sort of velocity to build up to 'bang'
the rotor into the stator.

Perhaps there are some motors with gaps big enough to
give room for that heavy rotor to accelerate to
damaging speeds; but I'm not aware of them.

Most of the motors I've converted were size-34 2 and
3 stack; with a few size-23 triple-stack and a couple
size-42 double-stack. Again, none were damaged in
any way.

It is certainly true that any particles of steel which
get into the motor have the potential to cause problems.

Note however, that many contaminant particles simply get
"ground up". In fact, as a point of interest, in
the most modern stepper motors, the gap is so small
that virtually -any- particle will engage both
rotor and stator; and you can feel it when you
turn the shaft.

The manufacturers state that this is a normal condition
and is not a cause for concern; as the torque of the
motor is much greater than the torque required to
'grind up' the particle; and the motor will in fact
do so the first few times it's run. That's straight
from 'the horse's mouth' i.e. the manufacturers we
OEM motors from.

best of luck with your projects,

Richard