| 摘要 |
PURPOSE:To interrupt abnormal currents quickly even when a circuit breaker is thrown again by making input currents flow through an amplifier circuit by the blown off small-capacity fuse and tripping the circuit breaker by output currents. CONSTITUTION:When driving current I from a control circuit CTL or a transistor Q2 are made to flow continuously, a small-capacity fuse F2 is blown off in a set time. Since a transistor Q3 is conducted at ground potential through a point C, a resistor R1 and the transistor Q2, the base currents IB of the transistor Q3 are made to flow. Amplified collector currents are made to flow through the trip coil of a none-fuse breaker NFB through the emitter and collector of the transistor Q3 from a point D, and reach a grounding. Currents sufficient for operating the trip coil of the breaker NFB are made to flow instantaneously, and the contact of the breaker NFB is brought to an open state. Even when a circuit breaker 3 again thrown, abnormal currents are interrupted quickly. |
