| 摘要 |
<p>One/off switch is for electrical equipment only on for a short time period. The switch is held operated magnetically but whilst operated the magnet warms up and loses its magnetic property so that the switch releases. The moving arm (1) of the switch carries a permanent magnet (11) which, when the switch is manually operated (6), closes onto a nickel-iron fixed ferromagnetic contact (4). Operation tensions the moving spring contact (1) which is magnetically held operated. In the operating condition, current heats a resistive component (42) in the circular resistor/ferromagnet structure so that at a certain temperature the ferromagnet loses its magnetic properties and the switch releases due to the spring nature of the moving contact (1). The ferromagnetic regains its magnetic properties on cooling.</p> |
