Electromagnetic pulley with a ferromagnetic shunt in zone of unloading

In this paper on the basis of the consideration of forces acting on a ferromagnetic body in the unloading zone of a pulley separator, the existence and the length of the return zone are determined, the body hitting into it comes back to the pulley, without unloading; it is shown, that the efficiency of the offered application (between return run and pulley) of a ferromagnetic shunt-plate of trapezoid form for a decrease or liquidation of the return zone-is determined by the degree of decrease of the magnetic field force in comparison with the friction force of an unloaded body on the surface of a conveyer belt. From an analysis of the magnetization of a shunt in the zone of unloading of the pulley and the solution of the equation of an unloaded body motion the possibility of using shunts of two forms is determined: a continuous isosceles trapezoid, reducing the magnetic field force, and an isosceles trapezoid with triangular opening increasing the friction force; the analytical relationship of forces, acting on a ferromagnetic body unloaded from a pulley, is obtained and it allows to choose the optimal geometry of a shunt. It is determined analytically and confirmed experimentally the better efficiency of application when unloading plane bodies of shunts with opening and when unloading cylindrical bodies of continuous shunts.