Theory and performance of the disc-type electromagnetic particle clutch under continuous slip service

Applying Mohr-Coulomb theory to the porous powder medium of the magnetic particle clutch, the shear resistance of the powder is computed in terms of cohesion and the internal angle of friction of the particles. The analysis of the clutch in toroidal co-ordinates yields the overall reluctance of the composite clutch assembly. The maximum torque transmitted by the clutch is derived from these factors in terms of the known excitation and clutch parameters. Shear strength, permeability and torque are correlated with extensive experimental data obtained from two clutches using electrolytic iron particles of six sizes in the range 40¿¿300 ¿¿m at various shearing velocities and excitations.