I'm using 3 - A4988 driver modules as of now, I will expand to 4. With a CNC shield that pins into the Arduino board from the top. I have 3 - Stepper Motors, Nema 23 Bipolar 2.8A269oz.in/1.9Nm the motors are rated from 24v-36v. I am running them at 30V, using a MENZO 12v 30a Dc Universal Regulated Switching Power Supply (is it possible the amperage is to high?). I have an adjustable transformer, so I could reduce the voltage. I also used a zinc thermal paste to attach the heat sinks, however I just ordered some Arctic Silver 5 AS5-3.5G Thermal Paste to use instead. The controllers heat up significantly. I was just trying to cut a few small letters in a piece of wood and the machine started skipping steps after only 2 letters and the heat sinks were very hot? I know there is a way to resolve this, I just don’t know what it is.
Any help would be greatly appreciated
Please let me know if anyone has a possible solution,
The A4988 is not an appropriate driver for NEMA23 steppers. 2.8A coil current is way too high for the A4988. The TB6560 is a candidate. They will not fit on the CNC shield, though.
What is the coil current limit on the A4988 driver set to?
The A4988 drivers are good for 1.0A with no heat sink or additional cooling (fan). A bit more with heat sink and up to 2.0A with heat sinks and forced air cooling (fan). That is for quality drivers like from Pololu. Cheap Chinese drivers will be less.
That said, the drivers will run hot, naturally. Hot enough to be painful to touch. If they get too hot they shut down.
The remedy is to set the coil current to a reasonable value and/or use a heat sink and active cooling. Really, in this case, acquire appropriate drivers.
I think that you are frequently confusing voltage and current. The motors of 2.8A @24-36V will hardly work with a 12V supply. And you cannot get 30V out of a 12V supply. OTOH 2.8A*36V means about 100W per coil, your PSU and driver board should have 200W per motor!
Thank you so much for the response. I am very new to this, I built the machine. The woodworking and mechanical aspect is a breeze for me, however the controller and software aspects have been a challenge. I bought most of the parts from amazon and have been learning as I go. The controller set that I'm using came with the CNC shield. I bought bigger stepper motors, as I thought that I would need them since the CNC cutting area is fairly large. I'm sure I could have used smaller motors. However, I have them now. Since you're clearly more seasoned than I am, do you have any thoughts on a more appropriate controller for these steppers? They're rated at 2.8 amps.
I know of no stepper driver modules that will be appropriate for those motors that will directly fit on the CNC shield. You can still use the shield and wire from the headers on the CNC shield to the drivers that you choose.
Thank you for the reply. I am new to this. I built the machine myself, the wood working and mechanical aspects are no problem for me. However, the software and control aspects of it are a challenge. I am reviewing the Pololu site you suggested. I’ll give them a try.
I built a small woodworking machine to do engraving and carving with a Dremel. It works very well for what it was made. It uses 3 NEMA17 steppers and an Uno with CNC shield. I use all free open source software (CAD, CAM) to create the projects. If I can help with your machine I would be glad to.
