Does anyone know if the openbuilds blackbox can control lego technic motors or alternatively nema 8 stepper motors? LEGO Technic Motor Use CNC Stepper Motors with LEGO Technic
doubt it can do the motors, they are DC motors, right? the steppers will move but might be overpowered, I don'tknwo what the low end of the current adjustment is but it might stillb e too much for those tiny motors. Yes, one could add a resistor in series with each coil, which will reduce the heating, but may have strange effects on other motor parameters.
Minimum is about 1.2A - likely too much for most NEMA8s I've seen. It's meant more for the NEMA17-23 range
hmm, I'm hoping to test out a NEMA 14 on the z axis to drive an acme thread, is that ill advised? Just checked the stats... Nema 14 Stepper Motor with Step Angle 0.9 deg Round, size diameter 36 x 12 mm Holding torque 7 Ncm (9.91 oz.in) Current/phase: 0.5 A and resistance/phase: 17 ohms
Way to small. 1.2A minimum (ideal for our 1.7A Max Nema17s). 0.5A max of yours needs more like 0.3A to run optimally. That figure is a Max rating, not a recommendation
Do again note, if its "rated 1.2A" thats the manufacturer saying "This is the absolute max - dare exceed it and it will be dead" Put 1.2A into continuously - and it will overheat like crazy. A 1.2A Max motor will probably like 0.8A, and even with that still burn your hand. Max rating is like the red line on your car's rev counter - you can't drive around at 6500rpm all day every day either. Just the same you can't run a stepper at Max Current. Ideal current setting would be lower than the maximum (always) BlackBox was designed as a power house. Give it a decent motor like ours: NEMA 17 Stepper Motor Not only is it rated to a max of 1.7A (making that 1.2A minimum setting a nice sweet spot for it) but also has low inductance (higher max rpm) and low coil resistance (fast acceleration)
Thanks, I will take that into consideration. It would be nice if the blackbox controller offered a way to even further drop down the current to the axis motors (Z axis in particular.) While I understand that a lot of people are using BB for CNC there are also uses for it where motor sizes could be scaled down.
Understood, but at this point it is what it is - plenty of DRV8825/A4988/Pololu drivers based boards for the low end of the market - not much space for us
True, although OpenBuilds is rather unique in that it provides a much higher quality and more complete solution (hardware/firmware/software/etc.).
