| 摘要 |
<p>In a proximity sensor an electrical circuit is formed by a slot 10 in an elongate conductive strip 11. The strip 11 carries a magnet 12 having a pole piee 14 protruding through the strip 11 at one end of slot 10. At the other end of the slot 10 pass laminations 15 which magnetically couple the electrical circuit and a multi-turn coil 16 on a former 17 attached to the strip 11. The coil 16 is terminated at an output pair 18. A ferrous object passing in the vacinity of pole piece 14 modifies the flux pattern at the pole face. The resultant flux changes, being tightly coupled to the electrical conductor 11 induce a low voltage high current emf into the conductor 11, which forms the primary turn of a current transformer. The secondary of the current transformer is formed by the close coupled coil 17, which has multiple turns, dependent upon the output voltage required at output pair 18. The invention overcomes the problem of providing a proximity sensor which can operate at a high temperature since the strip 11 may be uninsulated, without consequent danger of insulation breakdown, as with prior art multi-turn arrangements. </p> |
