Greetings:
I have these steppers #2267 working with the DRV8825 driver carrier, Arduino MEGA using the Accelstepper library. Only thing needed is the maximum RPM spec for this motor. The Accelstepper library uses parameter this when accelerating.
Thanks in advance,
The maximum step rate depends strongly on the voltage of the motor power supply and the load applied to the shaft, which are up to you. Trial and error works well to determine that parameter under typical working conditions. Be sure to set the current limit correctly.
Thanks for the speedy reply, Jim. Power supply is 13.8V 3a type as sold at Radio Shack. I went through the current calibration procedure and tweeked the pots “just a bit” as the motors were running while I judged the torque gripping with fingers. Just enough current to supply good torque and not heat anything up. Not scientific, but my sense is that all is well. The motor sketch runs for hours with no heat generated, but there is no load on the motors. Am trying to figure out what max speed number to put in the AccelStepper parameter. Sounds like there is no magic number. Currently at 6000 and all runs well. Will leave it at that. Thank you for confirming the suspicion.
Hello.
We have not characterized the maximum achievable speed of that particular stepper motor, but the pull-out torque curve for that stepper motor (which can be found in the datasheet listed under the product page resources tab) makes it seem like you should be able to achieve 5000 pulses per second (pps) in half-step mode with a 24V supply under at least some conditions (which would be around 750 RPM). Achieving that kind of speed might take many seconds of ramp-up and allow for very little torque, however.
As Jim mentioned, the actual maximum speed you can get is heavily dependent on your system, but the main things you can do to maximize your speed are increasing your supply voltage, making sure your current limit is set properly, and making sure your power supply can deliver the current your stepper motor is trying to draw.
Just to give you some perspective on how various parameters affect top speed, here are the results of some tests we performed with our #1207 stepper motor using a DRV8825 driver in half-step mode with the current limit set to 280 mA:
[ul][li]24V supply with a bare shaft -> 1500 RPM top speed (10k pps)[/li]
[li]24V supply with a fly wheel -> 2000 - 3000 RPM top speed (15k - 20k pps)[/li]
[li]12V supply with a bare shaft -> 1000 RPM top speed (7k pps)[/li]
[li]12V supply with a fly wheel -> 1500 RPM top speed (10k pps)[/li][/ul]
To get these speeds, we needed to ramp the motor speed up from rest over several seconds.
- Ben