Re: [CAD_CAM_EDM_DRO] STEPPER TORQUE THREAD

I machined a capstan that was a bit under 2.000 diameter . It was reduced
by 1/2 the thickness of the heavy nylon cord.

One end of the line is attached to a spring scale that is deadheaded (fixed)
. Several turn of cord are wrapped around the capstan loosely. The motor is
commanded to run at a specific speed. With the line loose the capstan slips
on the cord.
The line is gradually pulled tight until the scale reading is taken.
This gives the running torque. If you use a second spring scale you can
figure the torque very acurately in oz inches.
Then you measure starting torque and at various speed. Make your selve a
nice chart in advane with the motor nameplate info, the voltage of the
driver and the torque at starting, 50 RPM, 100 RPM, 200 RPM and 300 RPM etc
Dan
-----Original Message-----
From: Joe Vicars <jvicars@...>
To: CAD_CAM_EDM_DRO@onelist.com <CAD_CAM_EDM_DRO@egroups.com>
Date: Wednesday, April 26, 2000 8:05 AM
Subject: [CAD_CAM_EDM_DRO] STEPPER TORQUE THREAD

> Sounds like what we need is a simple way to dyno a stepper. Most of
>us (I think) are using surplus stuff. Alot of my motors don't even have
>nameplates. It is unlikely that I would be able to find manufacturers
>info on my larger motors. I guess I could take a motor of similar size
>and windings and compare. Mikrokinetics.com provides torque curves for
>lots of motor sizes, and all the different wiring schemes, BUT the
>torque curves are calculated using THEIR drivers at THEIR voltages,
>which can be very different from YOUR drivers.
> So if you really want to optimize your system you need to know the
>rough shape of your motor/driver power curve. Anyone got any ideas on a
>simple stepper dyno??
> peace
>
>
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