I am trying to spin a magnet around a hall sensor. I have designed all the gear box to be 1 to 4 meaning the nema 17 needs to spin at 1000 rpm -> 2000 rpm.
I am using a A4988 and tried a drv8825 to no luck. (300-350 ish rpm maxed out, No micro stepping, both the library of : Accelstepper, the standard a4988 library).
Is there a driver that would step this amount easily, i have tried 3 different types of clone nema 17. Would it be worth getting a genuine E3D stepper motor?
(Running 12V though a bench lab power supply, pushed to 15v for a blip to no help).
The AccelStepper library is not intended for high step pulse rates. And yet you will need acceleration to get to a high speed (as with any motor). Catch 22
Have a look at this Simple acceleration code. It is based on this Simple Stepper Code and I believe some Forum users have had it performing at much higher step rates than AccelStepper can provide.
You will also need a high motor supply voltage. The DRV8825 will work up to 45v I think. Make sure to set the current limit to protect your motor.
Having said all that, if all you want to do is spin something a stepper motor seems a curious choice - why not use a simple DC motor?
If you need more help with the stepper motor please supply a link to its datasheet. There are hundreds of different Nema 17 motors.
1000-2000 rpm is a very high speed for a stepper, unless it's geared up - which doesn't make much sense for a stepper as it's normally used for low speed high precision motion applications.
Indeed it sounds like you're better off with a regular DC motor.
I am using the stepper motor as I am creating a distributor, this will be doing the timing. If I go to this speed will the accuracy be lost. Got a 800 step motor to hope the 4 increase gearbox can step in 1.8 degrees.
As this is a university project if there is a certain type of stepper motor for this project let me know. (Got 2 motors from old printers and 1 from china)
Is it worth me creating a bigger gearbox and if so what rpm is the high range for a standard nema. (Need an output between 4000-8000)
Regards
Bob
bobthecooldad:
I am using the stepper motor as I am creating a distributor, this will be doing the timing. If I go to this speed will the accuracy be lost. Got a 800 step motor to hope the 4 increase gearbox can step in 1.8 degrees.
As this is a university project if there is a certain type of stepper motor for this project let me know. (Got 2 motors from old printers and 1 from china)
Is it worth me creating a bigger gearbox and if so what rpm is the high range for a standard nema. (Need an output between 4000-8000)
Regards
Bob
Please read post #3, NEMA type/number tells us nothing of the characteristics of the stepper, only is shape/form factor/physical size.
Please do some research into stepper performance.
What is stopping you from using a DC motor, gearbox and an encoder on the distributor shaft to give position feedback?
You must have resources at your university to learn about these motors.
Thanks.. Tom...
Stepper motors are really simple devices. Just coils.
Your speed is limited by the quality of the pulse
The pulse must be clean square waves.
The timing between pulses has to be even.
The speeds you are Describing are not where the stepper has power so are rarely used in that area.
Lab tests have pushed steppers much faster.
What to do?
Scope the pulse signals.
Make sure they are well defined and even.
Also the friction and angular momentum of the rotating part of the motor, and the pulse timing is going to be dependent on voltage and inductance of the windings (it's all very well to say "you need better pulses", but that may not be possible with practical circuitry!)
In general, stepper motors are not meant to go "fast"; for that you'd want a 3-phase "brushless" motor (except most of the low-cost motors of that type seem to be aimed at model airplanes, are are designed for higher RPMs.)
I understand and agree that stepper motors are not designed for USE at high RPM.
but the people who push limits and make things do things outside of the normal envelope can show us what is possible with existing technology.
Having followed the experiments with high speed steppers. The #1 problem was the pattern of the pulse.
Charging the coils is technology we have.
High speed can be attained.
I'm not sure what you found with pulse patterns. Essential is a high driver voltage that forces the required current flow through the coils fast enough.
Here the typical current limiting of stepper motor drivers enters the scene, because it's achieved by PWM of the motor current. Now the PWM frequency may interfere with the step frequency.
