Stepper Motor Acceleration

[Glamo]

Please let me know the acceleration time up to 500 RPM stepper motors. I also need deceleration time also. What was happening without deceleration time, is the motor jerk or slip?

Thanks

 

[barry]

It all depends on your load and your motor.

 

[Glamo]

Thank you.
My Motor is Soyo Nema42 SY85STH80-4208A Rotor Inertia 1400g-cm2, Detent Torque 1.2 Kg-cm and the load is 6kg.
However I am just trying without a load and see no more than 200-220RPM speed with no acceleration. First, what is the minimum acceleration tim up to 500-550RPM
Regards

 

[Glamo]

sorry
Motor's Inductance/P:3.4mH, Resitance/P: 0.75ohm and 4.2Amp per Phase

 

[barry]

Thank you.
My Motor is Soyo Nema42 SY85STH80-4208A Rotor Inertia 1400g-cm2, Detent Torque 1.2 Kg-cm and the load is 6kg.
However I am just trying without a load and see no more than 200-220RPM speed with no acceleration. First, what is the minimum acceleration tim up to 500-550RPM
Regards

And what's your driver? The motor should have curves on the data sheet showing speed/torque/acceleration

 

[D.A.(Tony)Stewart]

You must study Physics to calculate this.
For practical purposes, it is usually not the torque or the moment of inertia that matters, but rather, the maximum sustainable acceleration that matters! Conveniently, this is a simple function of the resonant frequency! Starting with the Newton's law for angular acceleration:
A = T / µ

Resonance must be minimized or dampened.

http://homepage.cs.uiowa.edu/~jones/step/physics.html
http://www.atmel.com/Images/doc8017.pdf

 

[CncHobby]

Please let me know the acceleration time up to 500 RPM stepper motors. I also need deceleration time also. What was happening without deceleration time, is the motor jerk or slip?

I bet 1 second will be enough, but will be depends on how the acceleration done.

With large moving mass no deceleration may damage the mechanical transmission parts, and the position probably will overshoot.

 

[D.A.(Tony)Stewart]

Risk of too fast acceleration is slipped steps.

 

[Glamo]

Thank you very much for all.
And thanks to Barry
My stepper driver is China's made, up to 6A and 1/250 micro step adjustable with dip switch. OK for me.
I cant find speed/torque/acceleration data.
Regards

 

[KlausST]

Hi

Risk of too fast acceleration is slipped steps.

or a complete stalled motor.


Klaus

 

[Glamo]

The effect of insufficient acceleration is very clear to see.
However
1. I am asking what is the effect of 0 deceleration
2. What is the min acceleration time up to 500RPM with no load.
3. My observation is: Motor can run up to 200 RPM with no acceleration and also it runs at 500 rpm with RC slope (not linearized), but I need real values (or formula) with 6KG load. Or experimental results.
Regards

 

[CncHobby]

1. It will loose some steps at the start, may then run or stall.
2. I can achieve 1200 rpm (8000 step/sec at 400 step/rev) at 0.4 second on my milling machine
3. Many factors influences, easier to experiment directly with the hardware.



Attached the screen capture of my excel calculation for this - done many years ago so i even do not remember how the calculation is :smile:.

 

[barry]

Really, this is a system question, not a stepper motor question. It all depends on the motor, driver and load. If you use microstepping, you might find that you can accelerate faster because you will eliminate certain resonances. And you may need a damper. There's no 'one answer' to your question. And if you use "0 deceleration" you will have big problems. NOTHING can stop instantaneously, and you WILL lose steps.