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Principle of the leakage protector The leakage protector consists of three components: a tripping circuit, an overload protection device, and a leakage detection circuit. The overload protection device consists of thermal elements EH1 and EH2 made of bimetallic strips. The leakage protector is installed in the circuit, with its primary coil connected to the power grid lines and its secondary coil connected to the trip device within the leakage protector. Principles of the wiring diagram for residual current devices, methods of wiring residual current devices, and a detailed explanation of the wiring method for three-phase residual current circuit breakers. When electrical equipment is operating normally, the current in the circuit is in balance; the sum of the current vectors in the current transformers is zero (current is a vector with a direction – the direction in which it flows is indicated as “+”, while the returning direction is indicated as “–”. The magnitudes of the currents flowing back and forth in the current transformers are equal, but their directions are opposite, so they cancel each other out). Since there is no residual current in the primary coil, the secondary coil is not induced, and the switching protection device of the leakage protector operates in a closed state. When the equipment enclosure leaks electricity and someone comes into contact with it, a shunt current is generated at the fault point. This leakage current flows through the human body, the ground, and the working ground, returning to the transformer’s neutral point (without passing through the current transformer), which results in an imbalance in the currents entering and leaving the transformer (the sum of the current vectors is not zero), thereby generating a residual current in the primary coil. Therefore, the secondary coil is induced, and when this current value reaches the operating current threshold set by the leakage protector, the automatic switch trips, cutting off the power supply. This article is from: http://www.weijizongbao.com/jishu/562.html