[Delboy]

Hi all,

I need help to determine whether a stepper motor will be suitable for the following application:-

4-6Ib (2-3Kg) mass is required to be moved 2-3in (50-75mm) at a frequency of 0-175 cycles per minute. Positioning accuracy is not critical although expected to stay within a approx 0.25in during anyone use. The device will be operated at upto 175 oscilaltions per minute for 15-30 minutes continuosly.

I have no idea whether a stepper motor can handle the kinetic energy created by moving this amount of mass at these speeds? If one can then what sort of voltage/currents will I be expecting to handle? (any reccomendations on motor supplier would be a bonus )

Once I can get a pointer in the right direction in regards to the base motor type and size I can handle the remainder of the project (control system, software etc).

Regards

[WayneHill]

The device will be operated at upto 175 oscilaltions per minute for 15-30 minutes continuosly...

If it is just a back and forth movement then you could consider a pneumatic or hydraulic unit with a switching relay.

[Karl_T]

Would your application allow a crankshaft and connecting rod type idea? That way the motor turns in one direction to give back/forth oscillation. Then, a stepper would work as would many other motor types.

Constant cw/stop/ccw rotation at that frequency would be hard on a stepper or most any motor type.

Karl

[Delboy]

Would your application allow a crankshaft and connecting rod type idea? That way the motor turns in one direction to give back/forth oscillation. Then, a stepper would work as would many other motor types.

Constant cw/stop/ccw rotation at that frequency would be hard on a stepper or most any motor type.

Karl

I thought this might be a problem, unfortuantely a fixed throw crankshaft will not suffice as I actually need to alter the total lateral movement from 0-3" and anywhere in betweeen.

The stepper motor seemed to offer the necessary flexibility in terms of total movement and frequency, if this is going to stretch the capabilities of the average stepper motor then I need to consider a new approach.

I assume linear motors will encounter the same problems, cw/stop/ccw motion of variable length will place to much strain on the system.

An alternative might be a screw drive but the motor will still need to stop and start upto 150 cycles per minute.

[Karl_T]

I'd consult with the tech. department with a vendor of linear motors. Years ago, I replaced an air cylinder on a shuttle device with a linear motor. It worked very well, and the vendor, Parker compumotor, had EXCELLENT tech. service. They even came out to the plant site.

I didn't suggest the linear motor at first because of cost, hold on to your shorts when you price them.

karl


Karl

[mcpltd]

If you want a linear motor i have some surplus with linear guides and linear encoders.

http://cgi.ebay.co.uk/Brushless-line...QQcmdZViewItem

http://cgi.ebay.co.uk/Brushless-line...QQcmdZViewItem

[Delboy]

I didn't suggest the linear motor at first because of cost, hold on to your shorts when you price them.

karl


Karl

:-) Now I see why $$$$

Thanks to all for the responses but at these prices this project just bit the dust.