Zinc oxide varistors major role in the electrical industry

Many TGE mov varistor for counter used in the product must use explosion-proof zinc oxide varistors, which is specified in the Design Manual: The controller does not allow the choice of non-explosion type varistor varistors, air-conditioning control panel functions as designed distinction, lightning varistor generally refers to the use of varistors between power line and the earth, sometimes leaving the voltage rise due to poor ground between line and ground, so the ratio between the line and usually use the occasion higher nominal line varistor voltage. Varistor in the circuit must be considered able to withstand the lightning over-voltage, over-voltage and over-voltage transient frequency effects. Lightning varistor and fuse or general discharge with the use of the power portion of the first stage ZNR varistor in parallel with the power transformer primary coil ends, with fuse tubes series circuit, surge voltage suppression.
Under normal circumstances, voltage, resistance zinc oxide varistors great can be achieved by Meg level (the current flowing through it only microampere level, can be ignored), in the open state, no effect on the circuit. But when you experience a power voltage exceeds the breakdown voltage, its resistance suddenly reduce design to a few tenths of Europe even in Europe, up to the current moment by thousands of amperes, ZnO varistor immediately turned on by the deadline, because it and power supplies in parallel, so soon the power fuse blows, the main circuit board to prevent burn out. In addition, when faced with a slight momentary power surge fluctuation (220 ± 10%), varistor buffer will absorb this flow Chung clutter, there are encountered lightning, transformers and other inductive circuit switching operation, instantaneous overpressure effect produced on varistor, its resistance suddenly decreases, the current through the large drainage role to play to protect the entire circuit, this effect is called over-voltage protection. Varistors ZNR common in the schematic representation.
Zinc oxide varistors can also be used as over-voltage protection. Over-voltage atmospheric over-voltage and over-voltage points. Atmospheric over-voltage caused by lightning: Operating overvoltage is due to mutations in the electrical system status, sharp electromagnetic energy caused by the conversion. TGE metal oxide varistor theory is mainly used for lightning induced over-voltage protection, over-voltage electronic devices (surge) absorption, relay contacts spark arrestor, transistors, thyristors, integrated over-voltage protection switch current.