1, air switch is a familiar name, and its correct name is air switch. The air switch is generally low voltage, that is, the rated working voltage is 1Kv. Air switch is a switching device with multiple protection functions, which can cut off and connect the circuit under rated voltage and rated working current. The type and protection mode of its protection function are selected by users according to their needs. Such as short-circuit protection, over-current protection, shunt control and under-voltage protection. The first two protections are the basic configuration of the air switch, and the last two are optional functions. Therefore, the air switch can also cut off the circuit under fault conditions (load short circuit, load overcurrent, low voltage, etc.). ).
2. The leakage switch is properly called residual current protection device (RCD), which is an air switch with special protection function (leakage protection). It detects the residual current, that is, the algebraic sum of instantaneous values of phase line and neutral line current (including three-phase unbalanced current and neutral line harmonic current) in the protected circuit. Therefore, the setting value of RCD, that is, its action current I δ n, only needs to avoid the normal leakage current value, which is calculated in mA, so RCD can cut off the grounding fault of the protection circuit very sensitively, and can also be used as a backup protection to prevent direct contact and electric shock.