The NEMA 17 stepper motors are running too hot from the BlackBox Controller. I have adjusted the axis current 'pots' fully counter clockwise against the stop. I tried the clockwise direction, but that only increases the heatup and cogging. There is more than adequate torque at this minimum setting, but the motors seem to be getting too much current, and I do not think they will last very long. The controller is used on a laser etcher using the X-axis, Y-axis, Y2-axis, and PWM/M3 signal. The system has accurate positioning and laser control, but has not been used very long in fear of damaging the stepper motors.
Where's the NEMA17s from? Blackbox at minimum outputs 1.0A - our NEMA17s are 1.7A. Heat is normal, putting a measurement to "hot" could help me judge if its problematic
The steppers are standard duty that I have had for several years. A measurement of hot might be that they are too hot to touch after only 3-5 miutes, and hot enought to generate a scortching smell. This system has used other controllers without over heating and acutally staying cool for long periods of time. I may has some settings wrong, as I have just used most default settings. The system seems to function properly in displacement and laser control. If it would help to have a print out of the settings, I will try to get a listing. Thanks
Find the datasheet of your motors, who knows, maybe they are tiny little 700mA coils or something. BlackBox is 1Amp minimum (as our NEMA17s are 1.7A) - 1A is a good minimum for most motors, but with your unknown ones its hard to know. Or consider getting motors from us, then you know they are 1.7A 3.0V coil motors, which works great with BlackBox
Consider the old popular A4988 Pololu drivers, at max they put out 800mA (; BlackBox is a couple levels above that!
what kind of speeds can you get from your steppers? right now I'm using some nema 17s from a delta 3d printer I took apart to use for my diy CO2 laser. They are rated for 1.7 but I think the torque is only 36 oz. I'm using them with my blackbox, but the other day I noticed they were getting hot. I can't seem to push them past 5000mm/min reliably.
Steppers are not inherintly 'fast' by nature. Also keep in mind Grbl's maximum steps per second limits - use larger tooth count pulleys - use lower microstepping - use higher torque motors
I am glad I found this post. I have just received the Openbuilds Blackbox and the Openbuilds Nema17 stepper motors. I also noticed they are getting hot, but I am unsure if it is too hot. I have not adjusted the current pots or the grbl settings in the Openbuilds Control software. The temperatures I measured were as follows: 1. 55 degrees after turning the system on. Measured after approximately 15 mins. Openbuilds Control software was not connected. 2. 58 degrees. Measured after approximately 5 mins. Openbuilds Control software was connected. The "step idle delay" is set to 255 ms. 3. 59 degrees. Measured after jogging the stepper back and forward for approximately 2 mins. Openbuilds Control software was connected. The "step idle delay" is set to 255 ms. Are these high temperatures? On another topic, where do I set the "micro-stepping" on the Blackbox? Thank you again for the help and the great products.
See https://docs.openbuilds.com/blackbox/ > Section 2.2.1 deals with current adjustment, section 2.2.2 with microstepping (We don't recommend changing it) (The whole BlackBox documentation is worth a read,as is Home · gnea/grbl Wiki so you know how all the components work together and how Grbl (the firmware) works and is configured) Stepper motors do run hot. If its our NEMA17s, current adjustment pot turned all the way down is a good starting point - turn up a little if you have skipping
Hi Peter, Thank you for the reply. I will review the complete Blackbox documentation. Are the temperatures I measured excessive?
Where do you have the current set to at the moment? This is mentioned in the section 2.2.1 documentation as well.
Hi Peter, Thank you for telling me to read the Blackbox manual. I have found the following image for the wiring for the Nema17 motor to the Blackbox. See the link below. docs:blackbox:connect-nema17 [OpenBuilds Documentation] Is this how it should be wired, based on the colours of the wires? Thank you.
If its our motors, yes. If is not, see docs:blackbox:faq-identify-motor-coils [OpenBuilds Documentation]
Thank you, Peter. I will re-wire now and set the current anti-clockwise for the minimum setting to start.
If it was working before, and jogging the right directions, it was in order? There are 4 valid combinations that allow connection two coils to 4 pins - if you get it wrong it will not spin. If you get the combinations right but the order wrong it will work fine just reversed.
Think I found the answer to my overheating issue too. I am using a 24V 0.6A stepper motor for my custom build z-axis, everything works great except that is overheating. This is the product name "T6 Mini Lead Screw Motion Stepper Motor Stroke Linear Guide Rail Slide Actuator 3D Printer Kit CNC+28 Step Motor50-200mm". These small linear rails do not seam to come in >1.0A versions. Is there any modifications I can do in order make this work? Maybe something to lower the minimum 1.0A to a 0.6A?
Thank you for your reply. Because of the specific application I am doing, need to reduce weight as much as possible on the z-axis. Short than replacing the stepper motor, I am assuming your reply means there are no modification that can be done?
a Nema17 motor can have many different electrical characteristics for the same size and weight of motor, so you will be able to find a physically similar motor with a higher current rating, low voltage, and low inductance.