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Topic: Stepper Motor required to turn once a day (Read 477 times) previous topic - next topic

Fasbinder

Looking for Suggestions.

I have project that requires a take-up spool to advance and pull filter media exposing clean media within the machine once it gets clogged. To provide project context, I have a new 50 yard 50-micron roll of filter material (media is 7 inches /180 mm wide and a full roll has a 7 inch / 180 mm diameter.) On the smaller and littler side. The media free end is laced through my machine (minimal friction) and attached to the take-up reel. (which is also 7 inches / 180 mm wide and empty has a 1" inch / 25 mm diameter) The plan is to have the take-up reel directly mounted to my Nema 17 stepper motor (One I had on the shelf / Specs below) on center with a flange mount to drive and advance the spool. (one rotation of motor / One rotation of take-up spool) The motion is to pull the new filter material into the machine and spool up the used media on the take up reel.

I have the trigger mechanism figured out and code written to trigger the stepper motor using an UNO. I have the code figured out to advance the take-up reel the required amount of motor steps to advance the media the same amount each time (taking into account the changing diameter of the take up reel as it loads media.) Number of steps decreasing with each advance.

Tolerance for holding the stepper motor in place between advances is very wide.

I have everything functioning on a prototype setup using a 28BYJ-48 Unipolar Stepper with ULN2003 but now I need to change the motor driver and use the Nema 17 motor.

I am looking for advice on the following questions

1.) What stepper driver would you suggest for the motor listed below?

2.) The media gets clogged only about once a day so the trigger advance will be once a day as well. Really do think I need to keep the motor charged for 99.9% of the day, wondering if it will get hot / wasting energy just waiting to be advanced. Is there a way through the driver to cut power to the motor until the call for movement is needed? Suggestions?

3.) Once it is all setup, I will be powering the stepper motor with a 12v power supply. Reading how you should not power both the motor and the UNO with the same power supply. How would you suggest powering the UNO. There will be no computer in the area of the machine.


Nema 17 Step Motor         
Phases 2
Drive Voltage12-24 VDC
Resistance 1.65 +-10% Ohm / Phases
Holding Torque>=5.5kg-cm (77oz-in)
Rotation DirABCDA CW
MAX Slewing PPS 2500 PPS
HI POT AC600V/1mA/1S
Rotor Inertia 68c.gm3
Step Angle 1.8 +-5%
Rated Current 1.68A / Phases
Inductance 2.8+-20%mH / Phases
Detent Torque 0.2 Kg-cm REF.
Max Starting PPS 2500 PPS
Insulation Resistance >= 100M(Ohm) DC 500V
Insulation Class B
Weight .35Kg



groundFungus

#1
Jun 25, 2019, 03:56 am Last Edit: Jun 25, 2019, 03:57 am by groundFungus
The DRV8825 (Pololu is a source and has a good page on their use) would be a good choice of driver.  That driver has an enable pin to control its output stage (turn off power to the stepper coils).  Use a buck converter to drop the 12V to 5V for the Uno.

PaulS

Quote
3.) Once it is all setup, I will be powering the stepper motor with a 12v power supply.
That is the minimum you can use. Using a higher voltage power supply, that can supply an adequate amount of current, would be better.
The art of getting good answers lies in asking good questions.

Fasbinder

Thx for the comments.

Will read up on the DRV8825 and the buck converter.

PaulS - Based on your adequate amount of current comment, how would you suggest I power it?

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