Hello,
I will be using 12V power supply to drive five Nema 17, 3.68V, 2.3A,126 oz-in stepper motors through Arduino + Ramps. Are there any suitable drivers (preferably 0.6"x0.8") for those motors, giving that I will use heatsink + air cooling? I don’t care so much about the noise or super microstepping, I need to get the most torque from the motors.
And if there is no suitable driver for those motors, what about the alternative version of the same motor, where the rate current is 1.65A, but comes with bigger resistance, inductance and higher voltage (don’t know the exact voltage)?
Thanks
We do not have any driver boards that can provide that much current continuously under our standard test conditions (which are done without a heatsink or forced air cooling). Generally, adding a fan and heatsink will increase the current handling of the driver board. We do not have much specific advice for how to design a cooling system and the degree to which the current handling will be increased depends on the design. In general, it might be possible to get a 40-50% increase with a well designed cooling system.
Our TB67S249FTG Stepper Motor Driver Compact Carrier boards will fit into the driver sockets of a RAMPS board and can deliver approximately 1.6 A/phase continuously without a heat sink or forced air flow. We also have a larger carrier board for that driver (with more heatsinking built into the board) that can provide 1.7A/phase, though you would need to make some sort of wiring adapter to use it with your RAMPS board. Also, this driver has an optional Active Gain Control feature that uses feedback from the coils as it is driving them to determine the torque load on the motors and reduce the current if the toque load is reduced. We have tested that feature in a 3D printing system here and did not notice any differences in print quality when using it. If your torque demand varies, you might be able to use that feature to set a higher current limit.
I suspect the biggest tradeoff for the other stepper motor you mentioned is that it would have a lower maximum speed. Using a higher supply voltage can offset that, though. You might see if you can find datasheets for those motors and if there are pull out torque curves in them, that should give you a sense of how the maximum speed might vary between the two.
Thank you so much for the prompt answer!
Looking at the comparison table, AMIS-30543 also seems like a good choice to me for the bigger continuous current. I hope it will hold around 2.3A with enough cooling.
Thanks again!
The AMIS-30543 Stepper Motor Driver Carrier board can handle a bit more current than either of the TB67S249FTG carrier boards I mentioned and, in general, the AMIS-30543 has a lot of interesting features. You should be aware that you will need to make the wiring connections for an SPI connection to each of the drivers and your code will need to perform some initialization over that interface before the driver will move a stepper motor. We have an Arduino library for doing this on the “Resources” tab of the board’s product page.
Thank you for this clarification. Lastly I wanted to ask if the TB67S249FTG compact carrier board is directly interchangeable with DRV8825 on RAMPS 1.4 boards. Is there any additional wiring that needs to be done, related to the AGC pin being different from SLEEP pin on A4988/DRV8825? Are there any specific settings that I need to adjust in the software (I will be using latest Marlin to control a CNC milling machine).
The compact carrier board should work with a board like that RAMPS board that works with the DRV8825 driver without any hardware modifications. You might need to check the microstepping mode selection table to verify the driver will be in the microstepping mode you expect it to be. Generally, you might need to make some changes to how those pins are set to change the microstepping mode (I think the RAMPS board uses jumpers to do that) or make some changes in your firmware to account for a change in microstepping mode.
The AGC pin on the carrier board can be connected to the !RST pin next to it to enable AGC (the carrier board has a 20K ohm pull up resistor on the !RST pin). You might check that pin in the socket on your RAMPS board to see how those pins are connected to the rest of your system. AGC is handled directly on the driver IC, so no software changes should be necessary to use that feature.
