| 摘要 |
An earth leakage protective circuit has a contact breaker with its contacts (CB) in the live line (L) of the current supply. The coil (LI) of the circuit breaker has connected with it a semiconductor switch (CSR1) which is rendered conducting when earth leakage is detected by a circuit including a balance transformer (CT2) and an IC amplifier (IC1). To protect the load circuit additionally against loss of neutral, a second semiconductor switch (CSR2) is connected in series with the coil (L1). The second switch is controlled by a detector circuit (R9, D8, R12) which renders it conducting when the neutral supply line (N) becomes open-circuit, so that the circuit breaker contacts (CB) are opened. |
