Trip control circuit for circuit breaker for detecting ac and/or dc

Abstract

The present invention provides a trip control circuit for a circuit breaker capable of breaking a circuit when a fault current occurs due to a DC current component, as well as an AC current. The trip control circuit comprises a current transformer that has a core allowing a circuit to pass through and a secondary coil for detecting a current flowing on the circuit and providing a current detection signal; an oscillation circuit section that configured to apply an electrical signal to the secondary coil to increase a slope of a hysteresis loop of the current transformer to allow the secondary coil to detect a DC current and an AC current; and a trip determining circuit section that configured to compare a current value indicated by the current detection signal with a predetermined reference current value.

Description

technical field [0001] This disclosure relates to a trip control circuit for a circuit breaker, and in particular, to a trip control circuit for a circuit breaker that is capable of flowing on a circuit by detecting even a circuit that cannot be detected by existing circuit breakers The DC current component and the AC flowing on the circuit, to cut off the circuit when the overload current of alternating current (AC) or direct current (DC) or the leakage of AC or DC occurs. Background technique [0002] A circuit breaker is a multi-pole AC power circuit, typically a three-phase AC power circuit (hereinafter, simply referred to as a "circuit") that is unbalanced between multi-pole (phase) currents due to leakage or in at least any one phase An electrical device used to cut off a circuit when an overload current occurs in the current flow. [0003] In particular, a circuit breaker capable of breaking leakage current is called an earth leakage circuit breaker (ELCB). [0004]...

AI Technical Summary

Problems solved by technology

[0009] However, in such figure 1 In the circuit breaker shown, the current detection means 20 is a transformer, and thus it is able to detect the AC component of the circuit, but the DC component flowing on the load 50 cannot be induced to the secondary coil, and therefore it is impossible to detect DC component

[0010] Therefore, the trip control circuit of the circuit breaker according to the related art cannot cut off the circuit when an overload current or leakage of a DC component flowing on the load occurs.

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