I want to control a 3.5 turn needle valve with a servo motor. The valve will control according to the flow given by a Flow-meter, i need to specify the servo to rotate the valve to a certain degree that matches the Flow that i want. I dont know wich servo buy. I looked online and found a multi-turn servo like this 2000 Series 5-Turn, Dual Mode Servo (25-3, Speed) (servocity.com)
The valve is this ABAC - VA2 VÁLVULAS AGUJA CON BONETE ROSCADO
I want your help for choosing a servo. All will be controlling via Ardruino.
And how will you attach the servo shaft to the needle valve shaft? How much torque will be required? Will you need to completely shut off the flow with the needle valve?
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The very first step is to determine the maximum torque required to turn the valve handle.
Choose a motor/gearbox/servo that can provide at least twice that torque.
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Maximum torque will be required to OPEN the valve from a completely closed position.
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The attachmente probably with be with a 3d printed piece, but i didnt finished designed that part.
The maximun torque will be 10.2 kg.cm. I will need to shut the valve completly yes.
Then that is the minimum required for your servo search.
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Thanks but i dont know the diference between a sail-winch servo and a multi turn servo. Or if i could use a continuos rotation servo.
The servo you linked in your first post has a stall torque greater than your requirement if you power the servo on 7.4V. For a coupler, It also will accommodate the number of rotations you require. I would recommend a splined coupler from the same source. You can use one of the 6mm clamp style and either enlarge the clamp end to fit a larger valve stem or shim it to a smaller size.
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Post the data sheet
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Do you have the valve? Can you measure the valve stem diameter?
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About 7.4 mm
Then you could drill one like this out to fit your shaft
The 8mm version may collapse enough to use if you don’t want to drill the 6mm one. I think this will be more reliable than a 3D printed version with the torque you’re talking about.
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Wow thank you so much. Ill take a look.
Also that GoBilda servo is available in a much higher torque range at a lower voltage (5V) for the same price.
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Oh nice, could you link it to me?
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Bear in mind that a multi turn servo doesn’t have the same resolution that a 180º one does.
It has to move farther per microsecond of signal because the control range is 500-2500 microseconds for 800º of travel. That may or may not matter for the fine control of your valve.
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Oh that might be a problem, given that for some cases i have to turn the valve like 30 degrees or less. It will take a few more seconds to adjust maybe.
Sorry for this question but what de 25-2 means?