I have a 24-volt motor (RK-370CA-12530) controlled by an L298 Dual H-Bridge. I am also using a recycled computer power supply to power the motor, the H-Bridge, and an Arduino. The power supply has GND, -12V, 3.3V, 5V, and 12V outputs. I was wondering if I could use the -12V on the GND of the H-bridge and 12V on the VIN of the H-Bridge to get 24 volts to the motor. Will this break the H-Bridge or cause anything else to fail?
The GND on your H-Bridge circuit should be connected to the GND of the control logic (Arduino) and the GND of your power supply to have a common ground.
If you connect -12V to the GND of your H-Bridge, your Arduino GND should also be connected to the same electrical potential.
If, let’s say, you are powering your Arduino with USB, you would have two electrical potentials connected to the GND at the same time which will probably damage your Arduino or your USB port.