Magnetic bridge permanent magnet relay

Abstract

An electromagnetic actuator comprises a first polar plate 101 having a first head portion 111, a second polar plate 102 spaced apart from the first plate and having a second head portion adjacent the first head portion, a permanent magnet 104, and an armature 103. The armature is movable between a closed position where it contacts the head portions and an open position where it does not contact the head portions. The plates each comprise an opening window 131 or cutout passing therethrough with an upper bridge 115 disposed on one side of the window and a lower bridge 116 disposed on an opposite side. The window of the first plate is aligned with the window of the second plate. The height H1 of each upper bridge and the height H2 of each lower bridge are dimensioned such that 0.5 x H1 ≤ H2 ≤ 5 x H1. At least part of the upper and lower bridges may be magnetically saturated by the permanent magnet when the armature is in the closed position. A coil 106 may be wound around the plates and pass through the window so that a current flowing through the coil reduces the magnetic holding force of the permanent magnet. Figures 1 and 4