Magnetic Coupling Torque Calculator
Enter pole count, inner and outer ring sizes, the magnet-to-magnet air gap (shell plus running clearances) and magnet length for a preliminary pull-out torque (N·m) of a coaxial magnetic coupling.
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- Engineer check on request
1Magnet rings
2Air gap and length
3Grade and temperature
Pull-out torque 36.3–51.5 N·m
Pull-out torque
36.3–51.5N·m
≈ 370–525 kgf·cm
Maximum static torque before the rotors slip · at 20 °C
Peak at a rotor offset of about 23°
Upper end: 2D model 57.8 N·m × end-effect factor 0.89
Pull-out torque is not the rated torque: size the coupling so the load torque, including start-up, stays well below it.
Preliminary estimate. 2D analytic (subdomain) solution, exact under its idealisations — radial magnetisation, full pole arcs, μr = 1 magnets, both rings at the same temperature, a non-magnetic shell, static (no speed or shell eddy-current effects), ideal steel yokes (μr → ∞) — with a harmonic-by-harmonic end-effect correction from an analytic model, not 3D FEA. The correction never raises the 2D value. Upper end at maximum Br; lower end = upper × (Br min / Br max)² × 0.75, covering segment gaps, the real magnetisation, yoke saturation and assembly. We confirm prototype and production designs by FEA and a pull-out test.
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