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Rectifier evidence

Rectifier Bridge and Diode Module Testing

A shorted input bridge or output diode module can cause breaker trips, bright lamp-limiters, no output or repeated IGBT failure. Test the actual diode paths rather than trusting a visual inspection.

Single diode forward/reverse meter hookup, cropped and relabeled.
Single diode forward/reverse meter hookup, cropped and relabeled.
Dual diode module crop with English rating interpretation.
Dual diode module crop with English rating interpretation.
Three-phase rectifier bridge crop with English test-point guidance.
Three-phase rectifier bridge crop with English test-point guidance.

Repair interpretation

FindingLikely meaningNext step
Low reading both directionsShorted diode path.Replace the module and inspect downstream shorts.
Open both directionsOpen diode path or broken internal bond.Replace the module.
One bridge leg differs from the othersPartial damage or heat-stressed module.Do not power the welder until all legs are checked.