I am using the DRV8825 stepper motor driver. The NEMA 17 is rated for 1.2 A and the NEMA 23 I'm using says it's rated for 2A. I have two NEMA 23s and they both soon choke out (stop moving).
When I was using the carrier board from Pololu, the lower current worked for any motor (adjusted by the current limiting potentiometer). But it didn't have enough torque. So I made a PCB, put on the DVR8825 and attached a beefy heat sink (chunk of aluminum) and thermal paste between the two.
The issue could be a heating issue. But the new heat sink dissipates heat pretty well. I mean, it could be going into automatic shutoff. But then, that doesn't explain how the NEMA 17 always works and the NEMA 23s stop working at higher current after a 3-4 seconds.
I will try to experiment with my resistor decade boxes for a slightly lower current. This will lower the torque, but it might work out. Is there something else that might be going awry? I can go into further detail of the PCB design, but I believe the design in relation to heat dissipation is not the issue.
More information and testing...
The MCU is an ESP32. It is powered by a VX07805-1000 DC regulator: The https://www.digikey.com/en/products/detail/cui-inc/VXO7805-1000/7350297
When the ESP32 is powered via micro-USB, it seemingly runs indefinitely. When it's just the voltage regulator, it runs for about eight seconds. Then the NEMA23 stops.
I switched out a fresh VX07805-1000s. The same thing happens. After eight seconds, the NEMA23 just stops. Even if the ESP32 is plugged in (running indefinitely), and the micro-USB is taken out, it still stops after about eight seconds.
The heat sink is cool to the touch. After running it for a few minutes it gets warm. Either way, I think it's clear it's not a heat diffusion issue (related to thermal shutdown).
The voltage regulator's max output current is 1 A:
...seems to allow that?