Re: stepper motors

I have a simple method for testing stepper motor torque while running. An
acquaintance took his motor apart to see what made it tick. He noticed a
significant reduction in power after he reassembled it. He brought it over
to have me look at it. He told me what he had done. I measured the torque on
an identical stepper motorat 100 RPM's it had 140 oz inches of torque. I
then measured his at the same speed. It was only 90 oz inches.
Dan
-----Original Message-----
From: bobd@... <bobd@...>
To: CAD_CAM_EDM_DRO@onelist.com <CAD_CAM_EDM_DRO@onelist.com>
Date: Friday, July 02, 1999 2:30 AM
Subject: Re: [CAD_CAM_EDM_DRO] stepper motors

>From: "bobd@..." <bobd@...>
>
>There is a danger disassembling stepper motors!
>
>The ones with permanent magnets in the rotor are magnetised in situ within
>the stator or in a 'keeper' and transferred into the stator during
>manufacture. If you remove the rotor from the stator and then return it you
>will find that the motor is less powerful than it was. I did this very
>thing. I extended the rear shaft for a handwheel and that particular motor
>is now weak. Does anyone know how to remagetise it?
>
>Bob
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