I'm doing a G0704 build and have almost finished the enclosure. The X and Y axis are using Automation Tech's hybrid 570 OZ, NEMA 23 motors. The clearance between the Y-motor and the front of the enclosure is tight..both X & Y motors are dual shaft and this makes things even tighter. I can easily cut the back shaft off the Y motor to gain clearance but I would like more than this will give me!
So...the question. Because these are specific to Automation Tech, I haven't been able to find a single shaft motor equivalent. I can however find a NEMA 34 in 640 OZ and almost the same current draw..5.5 amps, and it's a ton shorter. I can make the 34 fit..what would be wrong with this swap if my driver is up to it??
It depends on the motor inductance. If the NEMA 34 motor has low enough inductance there will probably not be a big difference in performance. Higher inductance raises the ideal voltage requirement of the motor to keep performance high. If using a higher inductance motor you will still have the torque at low RPM, but the torque will drop off faster with rpm compared to a lower inductance motor. The other factor will be the rotor inertia, which will be higher on the NEMA 34 motor, which may affect the acceleration you can achieve.Having seen your build thread, I personally think the NEMA34 motor would have minimal affect on overall performance.
I use the 570oz motors on mine. Work great and cheap to replace should there be an issue. Seems like the plan for the enclosure specs didn't match or take into consideration the full travel extents with the current motors. "A ton shorter" ?? Maybe I'm looking at the wrong specs but from what I see, the Nema 34 (mounting face to back is 80mm) and the Nema 23 (mounting face to end of the rear shaft is 115mm) difference is only 35mm or 1.38 inch. Personally I'd alter/modify the enclosure instead of changing the machine/motors etc., especially if less than an inch and a half is that critical.
IMHO...1 3/8" is a whole bunch. The Y axis motor doesn't move and the current position does fit inside the enclosure but I would be comfortable with more than a 1/4" between door frame and the end of the Y axis motor. The NEMA 34 would give me that room. My son wants X & Y motor to be a match set so I'll whack the back end shaft off the Y axis 570 oz motor I have, print up a new, shorter plastic cover and call it a day.
The enclosure build has been twice as much work, both planning and fabrication, as all of the modifications that have been made to the machine proper! I can see why people use cardboard, shower curtains or just shine it on. Decent looking tin work ain't easy.
You could try Hoss's method of using a belt drive and tucking the motor back under the table. This would be the shortest mounting solution, and seems pretty straightforward to do...
Thank you for all the good ideas. I have solved this minor problem by cutting off the back end shaft on the stepper and will draw and 3D print a new, short cover for the motor which will hold the pin connector and help shield the wire entrance to the motor.
Stepper Motor Size/Application/swap Question
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