Adjustment of pull characteristics of lever magnet with variable reluctance

Lever magnets, often defined s magnets with variable reluctance or open C-frame magnets, belong to significant components of automation system, heir thrust being based on the force generated upon convenient curvature of flux lines within the magnetic field gained through specific geometrical layout of the magnetic circuit. Their main advantages include a relatively high tensile force at the beginning of armature path, especially with the noiseless operation that predestines such magnets for utilization in automation systems, electric-pneumatic circuits as well as in electric-pneumatic controls of wind music instruments. Other applications comprise electric switching gear, mainly multiple-pole contact relays with low noise operation. Pull characteristics can be greatly affected by supplementing magnetic circuit with n extra permanent magnet. This paper describes characteristics of this type of magnets and the impact of the extra permanent magnet on the resultant pull characteristics.