Stepper Motor Power Rating?

"Should I be thinking about them differently?" - yes. Think torque and speed. Manufacturers publish torque/speed curves for the motors (which also depend on the drive type (full/half/microstep, unipolar, bipolar, chopper, L/R etc) and the way the motor is wired (parallel/series)).

The wattage can be given as the rated current x the rated voltage.

I am surrounded by stepper motors cannibalized from everything from floppy drives to printers. Those that come with toothed belts are especially prized because they facilitate their application to telescope drives and control by microprocessors.

The problem is that I am a mechanical designer not an EE. My knowledge of digital circuitry would fill a shot glass and still leave room for a quart of beer.

Is there a book for guys like me? Something akin to "Steppers for Dummies?" A simple book designed for tinkerers would be fun too.

Thanks

L.J.

"BTW - I'm happy to try answering any specific questions if you get stumped"

That's both thoughtful and generous John and I appreciate both.

The main problem as I understand it is that controllers need to be programmed. I lack the programmers mental set and the skill level to write and debug such creations. Since it appears that there is no such thing as one logic circuit or program to fit all steppers and applications, then I am faced with the need to develop each one.

I'll continue to pursue this but my experience suggests that I while I might build the drive and solder up the circuit boards, I should leave the task for programming to someone better qualified.

Thanks for the support.

L.J.

No prob. Keep in touch.

John

There is an extremely wide range of possibilities for driving stepper motors. I too am limited in my ability to program them - I seem to have a mental block preventing me from understanding ladder logic, which is used by many PLCs (Programmable Logic Controllers) and motion controllers. For that reason I have used Galil brand motion controllers for my last several projects. Galil has what I consider to be a very intuitive language for programming motion. It is very similar to the old BASIC language, which I learned in the late '70s (and used for my first few stepper control projects).

They aren't cheap, starting at several hundred dollars, but I have found them quite effective, with excellent tech support.

My favorite motors are the size 23 (2.3") motors commonly found in old tractor-feed printers. They have enough power (torque) to move a lot of common loads without requiring exotic power supplies.

Just been having a think. This seems to be a bit of a recurrent problem; folks who want to drive steppers, willing and able to do some graft with the hardware, but stumped when it comes to the software side - be it PIC programming, PLC stuff, VB or whatever. There's also the problem of providing a simple user interface ("go 1234 steps at 56 steps per second", "do 5.5 revs at 2 rps" etc.).

I think that the user interface would be simplest to implement on a PC - especially as most of us are using PCs to read & post to CR4. This leaves the problem of getting step & direction signals out of the PC.

I don't mind spending some time programming up a user interface (I'd consider it fun), but I need a feel for how much people are prepared to lay out for the interface hardware. Let me emphasise that I am not selling anything, but I have a few ideas of commercially available kit for which I could provide f.o.c. software.

If anyone's prepared to answer this, I'll think some more. Fell free to pm me.

Further to the above comment, the amount of power that you can pump into the motor is dependent upon the speed of operation and type of drive. The average power during operation must not be higher than the DC rating but could easily be less, based on how it is driven and at what speed it is operated. With only a simple drive, both the power and the torque go down with increased speed.