| 摘要 |
<p>The invention relates to an electric circuit breaker with an improved undervoltage release device.
<??>The undervoltage release device (410) includes a non-ferromagnetic tube (436), a trip plunger (418) and a reset plunger (416) both of ferromagnetic material and disposed in the tube, an electric coil (414) for producing a magnetic holding force between the plungers which holds the trip plunger (418) inactive while the voltage across the coil remains normal, and a bias means (compression spring 424) which biases the reset plunger toward its lower position and becomes effective, when said voltage drops abnormally, to drive the trip plunger (418) to a trip position. The reset plunger (416) is manually operable (reset button 420) after each tripping movement of the trip plunger (418) to restore the latter to its home position, and is manually operable under normal voltage conditions to effect a tripping movement of the trip plunger for the purpose or manually tripping the circuit breaker. </p> |
