| 摘要 |
PURPOSE:To improve the durability and reliability by locking a contact driving movable iron piece in the attracted state and holding the movable iron piece with the magnetic intensity of a superconducting coil after the exciting power source for an energizing coil is cut off. CONSTITUTION:To excite a keep relay, an energizing switch 7 is turned on while a de-energizing switch 9 is kept in the off state. An energizing power source is fed to an exciting ordinary coil 6 from a battery 8, a movable iron piece 2 is attracted to an iron core 1 by the magnetic intensity generated by the exciting ordinary coil 6. A magnetic closed loop is formed with the iron core 1 and the movable iron piece 2, the induction electromotive force is generated for a holding superconducting coil 5 by the electromagnetic induction phenomenon, a current starts to flow through the holding superconducting coil 5. The current flowing through this coil 5 semipermanently continues to flow after the movable iron piece 2 is separated. When the energizing switch 7 is turned off under this condition, the magnetic intensity is maintained by the coil 5, the movable iron piece 2 is locked while it is attracted to the iron core 1, and a contact section 4 is kept in the on state. |
