| 摘要 |
591,480. Electromagnetic relays. BRITISH THOMSON-HOUSTON CO., Ltd. May 10, 1945, No. 11728. Convention date, May 10, 1944. [Class 38(v)] An electromagnetic relay has a U-shaped core which is enclose( throughout its lengtl in a sleeve of copper or other non-magnetic conducting materia in order to delay the flux decay when the energizing current ceases. The core is made by first placing a copper sleeve over a straight iron bar and bending the two together. When the bar is circular its diameter may be 0.6 of the external diameter of the sleeve. Fig. 1 shows a relay having a U-shaped core 2 covered throughout its length with a copper sleeve 3. Windings 19, 20 on the limbs of the core may be wound in the same or opposite directions. A pole piece 2a is attached by a bolt 4 to one end of the core and a rocking armature 5 is pivoted at 6 and carries a pair of contacts 13 which co-operate with two fixed contacts 11. The gap between the armature and core poles can be adjusted by a bolt 18 and the armature is biased away from the pole pieces by a spring 14 adjustable by a bolt 15. A brass or other non-magnetic shim may be introduced between the pole piece 2a and the adjacent end of the core to reduce the residual flux in the magnetic circuit and so permit armature drop-out at a low flux value. |
