| 摘要 |
<p>An electromagnetic switch comprises at least one pair of magnetically latchable electrical contacts (12a, 14a) operated by current flowing in an associated coil means (K1, K2), and an electrical circuit arranged to apply a first current in a first direction through the coil means to close the contacts and subsequently to apply a second current in a second, opposite, direction through the coil means to open the contacts. In certain embodiments the coil means comprises first and second independent coils (K1, K2) and the first and second currents flow in opposite direction in the first and second coils respectively. In other embodiments the coil means comprises a single coil (K1) and the first and second currents flow in opposite directions in the single coil.</p> |
