为什么漏电保护器的工作零线不能重复接地(国外英文资料).doc

为什么漏电保护器的工作零线不能重复接地(国外英文资料) The 2 principle of leakage protection The leakage protector is composed of zero sequence current transformer, a leakage tripping device, tripping mechanism, main switch, etc. the five part test button. If the protected equipment grounding fault current in leakage protector tripping device of the current exceeds a predetermined value, will appear immediately in order to cut off the trip switch, circuit fault. As shown in figure 3. In general, under normal circumstances, the phase current and phase volume is equal to zero. Thus, the phase current flux of induction in the zero sequence current transformer in the core and is equal to zero. At this time, because the two side of the zero sequence current transformer winding no output signal, the main switch is in the closed state, the power supply to the load direction. When grounding fault occurs, or the insulation damage, leakage, or touch the charged body, the main circuit current of each phase and is no longer zero. It will appear fault current flux generated in the annular core zero sequence current transformer, resulting in two secondary side induction voltage forced tripping coil excitation force, main switch tripping, cut off power supply circuit. From the above, the current leakage protector is Kirchhoffs first law: Based on complex current algebra of any node in the circuit and the inflow is equal to zero, i.e. I = 0. 3 leakage protection function and the scope of use Leakage protection device with sensitive action, cut off the performance time quickly. In building electrical design and construction as long as reasonable selection and proper installation, to protect the personal safety and prevent equipment damage and prevent the flame will have obvious effect. (1) when the body directly hit 220V charged body, leakage protector quickly with 0. second time quickly cut off the circuit. Then through the human body (usually the body resistance is 1000 Ohm) the electric current is 220/ =