| 摘要 |
The objective of the invention is to obtain an overcurrent tripping device with which it is possible to reduce the tripping time in response to a fault current, and to reduce the size of the device. This overcurrent tripping device, which detects an overcurrent flowing through a main circuit of a circuit breaker and actuates a tripping mechanism of a circuit breaker that is in a closed state, includes: tripping conductors (5) connected to the main circuit; a fixed iron core (4) through which the tripping conductors (5) penetrate, and which is energized by the excitation of the tripping conductors (5); a movable iron core (7) which is disposed facing the fixed iron core (4) across a magnetic gap, forms a magnetic circuit in cooperation with the fixed iron core (4), and is moved by being attracted by the fixed iron core (4) when an overcurrent flows through the tripping conductors (5); and a shaft (6) which is secured to the movable iron core (7), guides the movement of the movable iron core (7) and is linked to the tripping mechanism of the circuit breaker. Slits (4a) are formed in the fixed iron core (4) in a direction crossing the magnetic circuit, and magnetic saturation is suppressed by means of the slits (4a). |
