Sinardet :
That appears to be a standard single-channel driver board for the Shark controller. The board has four sockets, of which three are already populated. That one goes in the forth connector, and then the DB9 at the back becomes active with signals for it. The motors are indeed NEMA 23, but be sure the drive current (adjustable on the board, IIRC) is sufficient to achieve the torque you're trying to get from it.
Are you trying to use it outside the shark? Or are you trying to duplicate the y-axis drive motors for both sides?
If you're actually trying to drive two NEMA 230 280 oz-in motors with the exact same stepper commands, you'd be better off using a separate driver board for each motor.
I say this based on the fact that some people have experienced temporary driver board "failure" during a run due to heat. From what I remember, the drivers came back when cooled, but the wasted part did not
. So, driving two motors of the same torque would make that happen a LOT faster. Also, IIRC, the boards were set pretty close to their maximum drive current.
So, use two boards, and parallel their inputs, and supply the outputs to the motors separately. If you are PCB-modification savvy (e.g., you know what an x-acto knife is used for in that context....), you could parallel the logic signals from one driver board to the inputs of that fourth board's connector (which you previously disconnected). There's typically only three: Enable, Step and Direction, besides logic power, driver power, logic ground and driver ground.
If you're planning to use a drive motor different from the one already in the machine, note that tuning the driver electronics properly can be a little tricky. But, thankfully there's only one knob. So, set it high enough you don't lose steps and have enough torque, but not so high that the motor gets hotter and hotter during use. It should get warm, into the low 100's F, but not anywhere near 200F. If it does, back the current setting back.
Hope that helps, reply back to continue, if there's more to your need than I'm seeing.
Regards,
Rando