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Performance analysis of special electrolytic capacitor for frequency converter
Date of issue:2015-01-05 15:58:17  see:
1、 Judgment method of rectifier bridge damage
In the maintenance process of frequency converter, the fault caused by the damage of the rectifier bridge only needs to be detected with the resistance block of the multimeter. It is worth noting that the parallel rectifier bridge should loosen the connector to finally find the broken one.
2、 Causes of rectifier bridge damage
Professional inverter maintenance engineers should know why, the following is to analyze the main cause of rectifier bridge damage.
1. Quality problems.
2. The back stage circuit and inverter power switch device are damaged, resulting in the rectifier bridge passing through the short-circuit current.
3. When the grid voltage is too high, the varistor is burnt out, resulting in all over-voltage added to the rectifier bridge.
4. Because the frequency converter is not equipped with DC reactor and AC reactor at the input side, when the converter is too close to the power transformer of the power grid, and the middle line impedance is very small, the rectifier bridge is in the impact state of high amplitude sharp pulse current of capacitor filtering, resulting in premature damage of the rectifier bridge.
5. When the input phase is missing, the burden of rectifier bridge is increased.
3、 Replacement of rectifier bridge
The frequency converter maintenance engineer should replace it according to the correct replacement method to ensure no unnecessary secondary damage!
1. Eliminate the fundamental damage reason of rectifier bridge and prevent the damage again.
2. Replace the rectifier bridge to ensure reliable welding. Ensure the electrical safety distance with the surrounding components, and tighten the screws to prevent the high contact resistance and heating. If there is conduction and heat conduction with radiator, it is required to coat silicone grease to reduce thermal resistance.
3. In order to avoid the uneven current, the products of the same model and manufacturer should be used for the parallel rectifier bridge.

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