Patent ID: 7548146

Claim:
A power relay assembly comprising: a motor assembly and actuator assembly disposed in a housing; the actuator assembly comprises: at least one bridge assembly having one or more contacts arranged to provide selective electrical connection between contact terminals mounted on the housing; and the actuator assembly being attached to an armature of the motor assembly, the armature arranged and disposed to drive the actuator assembly; the motor assembly comprises: an electromagnetic coil assembly disposed around at least a portion of the armature, the armature is configured to be positionable along a stroke length; a magnetic pole piece disposed adjacent to an end of the coil assembly, the pole piece further comprising an armature seat configured to attract and receive the armature when the coil assembly is magnetized; and the armature seat having an armature ledge with a wall extending therefrom, the armature ledge and wall forming a recess into which the armature may travel, a tapered surface extending from the wall to a surface of the magnetic pole piece, the tapered surface extending circumferentially about the armature seat ledge such that tapered surface is positioned outside of the recess into which the armature may travel, the tapered surface being configured to provide a substantially constant attractive force along the stroke length.