Tuning different stepper motors.

zBeeble

I have two different stepper motors in my setup. Most of this is a fumbling around in the dark following some plans and making everything else up.

My two z-axis motors are 42BYGHM810P1. Their datasheet says max 2A.

My other motors (x, y and filament) are 42SHD001-24. The datasheet for this general type say 400mA.

The default for the duet2-wifi in the setup tool is 1200 mA. This seems to work fine --- the motors get hot (the small ones), but everything seems fine.

After reading this, tho, I increased my Z motors to 2000 mA and tried reducing the others to 400 mA. That certainly made them run cool --- but also made them quite week.

Am I reading these values correctly? Should I consider stronger motors so that I'm not over driving them?

Falkia

@zbeeble Not knowing how your printer is designed but is it possible to switch the z motors with the x and y?

deckingman

@zbeeble A good rule of thumb is to set the motor current to 85% of their rated current. So running 400mA motors at three times their rated current will certainly make them run hot and will shorten their life span considerably. The Duet documentation has good advice and recommendations https://docs.duet3d.com/en/User_manual/Connecting_hardware/Motors_choosing

zBeeble

@falkia said in Tuning different stepper motors.:

@zbeeble Not knowing how your printer is designed but is it possible to switch the z motors with the x and y?

Well... difficult at best. The electronics rest on a board that depends on the extra height of the z-motors. But this doesn't solve the problem ... it just means I'd be looking at the z motors having low current.

Falkia

@zbeeble it was just an idea because I think the z axis doesn't need so much power to operate comparing to x and y.

droftarts

@zbeeble Does your machine have a particularly odd setup? The 42SHD0001-24 motors, looking at the spec sheet here https://www.casunsteppermotor.com/product/42shd0001-24-stepper-engine-1-8-nema-17/ are very high resistance and inductance motors. Usually these are good for high torque, low speed applications, and will generate a lot of back EMF on direction changes. Generally you want faster motors on X and Y. See https://docs.duet3d.com/User_manual/Connecting_hardware/Motors_choosing#inductance for guidance on inductance.

The 42BYGHM810P1 motors on Z seem reasonable. This is the only datasheet I could find: http://archive.fabacademy.org/2017/fablabverket/students/100/web/assignments/week11/3302_0_Datasheet.pdf

Ian

zapta

@zbeeble said in Tuning different stepper motors.:

tried reducing the others to 400 mA. That certainly made them run cool --- but also made them quite week.

The specs I found for these one says 0.4A, 12V, 30 Ohms, 37mh, which is not good for high speed, unless if you use very high rail voltage.

I am not an expert, what they don't seem to be a good fit for 3D printers. What application were they used for?

zBeeble

@droftarts said in Tuning different stepper motors.:

@zbeeble Does your machine have a particularly odd setup? The 42SHD0001-24 motors, looking at the spec sheet here https://www.casunsteppermotor.com/product/42shd0001-24-stepper-engine-1-8-nema-17/ are very high resistance and inductance motors. Usually these are good for high torque, low speed applications, and will generate a lot of back EMF on direction changes. Generally you want faster motors on X and Y. See https://docs.duet3d.com/User_manual/Connecting_hardware/Motors_choosing#inductance for guidance on inductance.

"Particularly odd" as in I did it all myself in 2014 with only what was on reprap.org at the time as help and/or information? Then yeah.

The 42BYGHM810P1 motors on Z seem reasonable. This is the only datasheet I could find: http://archive.fabacademy.org/2017/fablabverket/students/100/web/assignments/week11/3302_0_Datasheet.pdf

These motors are "champs" ... but also large. I ordered a pair of 17HS4401S (the non-S was also available... couldn't tell the difference). They say 1.5A max.

Now... the feed motor runs "fairly" quickly. I'm assuming I can set the current to 300mA and use the 42SHD0001-24 for that still, fairly safely? My 1mm of movement there is 666 steps.

zBeeble

@zapta said in Tuning different stepper motors.:

@zbeeble said in Tuning different stepper motors.:

tried reducing the others to 400 mA. That certainly made them run cool --- but also made them quite week.

The specs I found for these one says 0.4A, 12V, 30 Ohms, 37mh, which is not good for high speed, unless if you use very high rail voltage.

I am not an expert, what they don't seem to be a good fit for 3D printers. What application were they used for?

IDK. Found them on eBay almost 10 years ago.

zBeeble

I thought it might help to post my m92 line.

M92 X100.00 Y100.00 Z5104.00 E666.00

... which all comes from measured movement.