I’ve attached my current motor setup that I’m using to drive a 6” ball valve with pressures of about 200psi on the valve’s input. I’m using a PID loop to control the valves position based on the pressure exiting the valve. The problem is that the motor is not as response, lack of speed, as I would like. Also, under these loads the motor has problems turning the valve. Therefore, it seems rather obvious that the motor is undersized for this load. I’m current at point where I wondering which way to go now. I’m trying to decide whether to go with a larger stepper motor/drive or cross over and use a servo motor/drive. I like the control that the stepper offers, but I’m curious if I can ever obtain the speed under these loads.
Here’s a brief description of the mechanical train’s movements. For the valve itself to be completely open it needs only to be turned 90 degrees. The planetary gear has a 60:1 ratio. So, it takes 60 turns on the input to complete one revolution on the output. Since the valve only needs to turn 90 degrees to be fully open the planetary input needs to turn, at most, 15 turns. Therefore, my motor needs to turn, at most, 15 revolutions. I don’t think I’ll ever need the valve completely open. So, I’m thinking, on average, that maybe around 10 turns would be a good place to start and I was wanting to accomplish this in around 1 sec. I would appreciate any comment or recommendations….tks!
