High Torque Stepper

[acetate]

I am looking for a high torque (>200 oz/in) stepper motor for use in creating a DIY proportional valve. I can only find MUCH smaller steppers (44 oz/in). I would prefer not to gear them because that will slow things down. I would like to have a full revolution be under 2 seconds. Does anyone have any ideas on a solution that might work?

[jed]

I guess I don’t understand the problem. I’m just learning about these, but it seems that MANY steppers are rated over 200 oz/in without being geared or too expensive. They are BIG, heavy, and eat watts but they exist.

Here is just one that I happened to find easily:
interinar.com/4023-833.html

4023-833 is a 1.8deg (200 steps/revolution) NEMA 23 step motor with 212 oz-in holding torque ( 150 N-cm ). Six wires 19" long allow connection to both unipolar and bipolar drivers. When connected as bipolar-series to bipolar driver the holding torque can be as high as 212 oz-in. This is very low inductance motor so it will perform excellently in any microstepping and fast application. The shaft is standard 0.25" diameter ( 6.35mm) and 0.75" (19mm) long. Motor is rated 4.6A for unipolar driver and 3.25A for bipolar driver in bipolar-series configuration. We recommend to use a DS335 Microstepping Driver with this motor in bipolar-series connection. To fully utilize this excellent motor we recommend higher voltage driver and power supply with minimum of 24Vdc.

[Tomek]

There are many such stepper motors, as noted above.

Look into the DIY CNC groups. That’s where you’ll find almost all of the info. Most of Pololu’s stuff is a very quality source for 3D printer projects and smaller CNC machines, but they don’t work as heavily in the higher power steppers (from my brief search the other day.)

But come back here for everything else you need- there’s a lot of great stuff.

Consider too, however, whether or not a continuous rotation servo motor or a geared 37D with an encoder will work for you application. Depends on how quickly and how accurately you need to rotate your device.