Handwheel Rim Pull & Turns-to-Operate Calculator
Find the rim pull force and number of turns to operate a geared valve, from the required output torque, gear ratio and handwheel diameter.
Method
Typical limits
Manual rim pull should stay below ~360 N (80 lbf) for routine operation. If higher, increase the ratio or handwheel diameter, or add an actuator.
Frequently Asked Questions
How do I calculate handwheel rim pull?
Divide the input (rim) torque by the handwheel radius. The input torque is the output torque divided by ratio times efficiency.
How many turns to operate a valve?
Multiply the valve travel (0.25 for quarter-turn, or the number of stem turns) by the gear ratio.
What rim pull is acceptable?
Generally under ~360 N (80 lbf) for manual operation; above that, gear up or motorize.
How do I reduce handwheel effort?
Use a higher gear ratio or a larger handwheel diameter.
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