Re: motors from floppy drives

On 13 May 99 , CAD_CAM_EDM_DRO@onelist.com entreated about
"[CAD_CAM_EDM_DRO] Digest Number 8":

} Message: 11
} Date: Wed, 12 May 1999 11:39:11 -0700 (PDT)
} From: Ron Wickersham <rjw@...>
} Subject: Re: motors from floppy drives
}
} hi David,
}
} suggest you double check the motors from your floppy drive. i've
never
} seen 200 step/rev motors used there, usualy 24 or 48 step motors are
used.
} if you have found 200 step motors, would you share the mfg of the
drives
} because a source of really small motors with fine steps would prove
useful
} to others.

the ones I'm using are from older halfheight 5.25" 1.2meg drives, Teac
and other makes. The motors are stock 'Japan Servo Co' NEMA 17 size,
running off 12v via various driver chips, inc ULM2003 and BA12004.

definitely 200 step per rev Ron, I have them on the bench, and
outputting 200 steps makes the motor go round once.

older 5.25" drive for 360kb disks used 100 step per rev

newer drives that use lead screws to drive the head mech are 10 to 48
step per rev types. the ones in 3.5" drive are 10 step per rev (the
ones I've tested).

note that some of the leadscrew types have no front bearing in the
motor housing, and so cannot be used once removed from the frame that
supports the far end of the leadscrew.

now we come to harddrives. 0lder MFM drives (the ones with 2 data
cables) used stepper motors for the heads. Some of them are quite
big in diameter, but flat, (seagate) and others are smaller (about an
inch across) than NEMA 17 but the usual square shape, and give 200
steps per rev. I have one of these at home with the end of the shaft
toothed to directdrive the mechanism.

steam and wind

--
David Forsyth DaForce A-T Iwr.Ru.Ac.Za
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