Zinc oxide varistors to protect the inverter application

 Lightning or lightning impulse voltage induced formation sometimes cause damage to the inverter. When the primary-side power supply system with vacuum circuit breakers, shunt opening and closing can also generate a higher voltage shocks. The drive side of the vacuum breaker opens once, formed by coupling the secondary side of high voltage surge spikes. To prevent over-voltage impulse voltage caused damage, usually at the input side of the inverter plus TGE metal oxide varistor application absorbing devices to ensure that the input voltage is not higher than the allowed maximum voltage during the inverter main circuit. When using the vacuum circuit breakers, the impact should be formed using an additional RC surge absorber. If the transformer primary vacuum circuit breakers, because to ensure the control timing before the first drive is disconnected vacuum circuit breakers.
Most factories are powered generator, or use the generator for a rainy day, when the generator has a fault, the output of the high-voltage inverter and electronic equipment often burned. This condition is often seen in our Shenzhen have had a wire drawing plant once it broke two dozen sets of 30KW inverter, discontinued ten days, causing heavy losses in the generator plant equipment to engage a lot of protection methods the effect is not obvious. Then join metal oxide varistor identification on the input of the inverter or instrument air switch, depending on the voltage 380V with a 821K, 220V with a 471K, so that when a high voltage varistor will be short-circuited, air switch trip, the protection of the inverter, Inverter failure rate is greatly reduced.
Note zinc oxide varistor must be connected to the output end of the air switch, parallel (three-phase triangular connection) wattage varistor size is not critical, a little input current is large is selected relatively large varistor or several varistors in parallel. When the TGE metal oxide varistor theory play a role in it will immediately complete a short circuit. Then switch also requires good air quality equipment, quick response and protect current is not too big.