| 摘要 |
<p>A solenoid (10) includes an armature (12) movable relative to a pole member between a first position and second and third positions, a bias structure maintaining the armature at the first position, and a dual coil assembly (14) driving the armature from the first position to the second and third positions. The armature is maintained in the second or third position by permanent magnet latching (24), residual magnetism latching or a holding current. A magnetic structure for the armature comprises first and second magnet segments (26, 28) and a spacer member for directing magnetic flux produced near ends of the magnetic segments to the armature. A drive circuit for the solenoid includes a delatch circuit for allowing the armature to be returned to the first position by the bias structure in response to loss of power. The axial position of an armature can be determined using comparative inductance test procedure.</p> |
