I am building a new controller for an existing robot. I need to know the voltage to send the motors. I don't want to remove the motors from the robot, but am able to take measurements while it operates using the old controller.
The power supply feeding the robot is 24 volts, so I assumed that I should send the robot 24 volts. I measured the current consumed by the motors at various speeds, and then used my controller to send PWM frequencies until the current consumed matched that of the original controller. What I saw was that the motors seemed to spin faster.
Does this make sense? Would the same current cause the motors to spin at different speeds, if the voltage was different? If so, how do I figure out what voltage to use?
Or could it be that I'm sending the same voltage, but the difference in PWM frequency from my controller and the existing controller is the problem?