Disc Clutch Torque Calculator: Uniform Wear and Uniform Pressure, with Power Transmitted
How much torque a plate clutch can carry.
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How this calculator works
Enter the friction coefficient and the axial force.
Enter the lining radii and the number of friction faces.
The calculator gives the torque for both models and the power.
Formulas used
- T = n\mu F\,\frac{R_o + R_i}{2}\ \text{(uniform wear)}
- T = n\mu F\,\frac{2}{3}\frac{R_o^3 - R_i^3}{R_o^2 - R_i^2}\ \text{(uniform pressure)}
- P = T\omega
Worked example
With the default numbers in the calculator above:
- Mean radius, uniform wear: 80 mm
- Torque capacity, uniform wear: 96 N m
- Mean radius, uniform pressure: 81.667 mm
- Torque capacity, uniform pressure: 98 N m
- Power transmitted at the speed (uniform wear torque): 15.08 kW
Change the numbers in the calculator to see the full working, every step, for your own case.
Common questions
Which model should I use?
Uniform wear for a clutch that has been run in, which is the safer, lower value. Uniform pressure for a new clutch.
How many friction faces does a clutch have?
Two for a single plate clutch, and the number of plates minus one for a multiple-plate clutch.
What safety factor should I use?
Design the clutch for more than the engine torque, often 1.25 to 1.5 times, to cover shock loads and wear.
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Got a question about this? Ask an engineering question and get a plain-language answer with references.
Further reading: Any machine design text (disc clutches).
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