Nema 23 and duett

Hi is it someone how knows if it is possible to replace the nema 17 motors for x and y with nema 23.
And if I do so would that help with skipping steps when I try to print faster?

/Joar

The description nema 17 and 23 do not neccessarily mean that the bigger motor is more powerfull. its just the physical mesurments of the motor. The Duet has Motordrivers that can give up to 2A driving power. So when you have a Nema 23 Motor that is capable of this motor current you can use them. Have a look at the motors datasheet for that.

When you switch the motors you have to adapt for the bigger size especially on your Y-drive.

You can use the command "M906 X1000 Y800 Z800 E800" to change the currents for your current motors. yust give the amount of current in mA for each axis. I have mine running on 800mA but X on 1A since this gives me a better result.

Also be aware that more current means more heat dissipation so have a look for that.

Thanks DasBasti
Most of the nema 23 motors on ebay is marked 2.5A and the nema 17 1,7A does this mean that the setting should be M906 X1700 Y1700 Z800 E800 for one of this nema 17? Or can i run a Nema 23 marked 2.5 A on M906 X2000 Y2000 Z800 E800.

/Joar

The NEMA17 motors of the Ormerod are also fairly "shallow". I got a bunch of generic NEMA17 motors for another project, and they were about 1cm deeper (still 43.2 x 43.2mm), and I guess that also usually means bigger motor coils and more torque. Replacing the stock motors with those would be reasonably simple (compared to NEMA23 motors), the Y motor would just need a modified bracket and a longer screw (the one that goes in the back).

If the stepper motor drivers on the Duet overheats, I would guess some small glue-on heatsinks on the drivers and maybe a fan blowing on them could make a difference in cooling them. If they're the kind with built-in overheating protection, it should be safe to just crank up the current as overheating will just temporarily shut down the motors (which shows up as a lot of missed steps).

You can run NEMA23 motors on the Duet, but you will struggle to get the full current to them. The stepper drivers will overheat and cut out, probably at around 1.4A. There is a reasonable amount of heatsinking on the board, but the driver chip has it's heatpad on the bottom of the chip, so I'm not sure how effective it is putting a heatsink on the top, but can't hurt. Also, a secondary fan pointing at the stepper drivers will help at high current settings. You can, of course, run any motor at a low current setting, it will just loose torque, and energise less quickly.

Check the Allegro A4982 technical specification/datasheet here for more info: [www.allegromicro.com]

Ian
RepRapPro tech support

Quote
Joar107
Hi is it someone how knows if it is possible to replace the nema 17 motors for x and y with nema 23.
And if I do so would that help with skipping steps when I try to print faster?

/Joar

Before you do that, have you increased the current to the standard motors? They are rated at 1.33A. Torque increases with the square of the current, up to the point where the iron core goes into saturation. As Ian mentioned, you may need to provide additional cooling to the stepper motor driver chips. Also check that the motor doesn't get warm enough to soften the plastic parts it is mounted on.

Which motors are skipping steps, and what do you have the motor current set to?

If you want to drive NEMA23 motors from the Duet, you could look for motors with lower current but higher voltage windings, and run the Duet from 24V. But you would need to do something about the heated bed, because if you put 24V into the one supplied then it will draw 20A, which is liable to burn out the bed, the wiring or the driver mosfet..

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Thanks for all the answears, I will go up with the current a little with nema 17 and ad heatsink and a fan to the drivers.
Thanks again/Joar