Rectifier evidence
Rectifier Bridge and Diode Module Testing
Use this route when the input breaker trips, the DC bus is missing, or output rectifier failure is suspected.
Rectifier testing table
| Device | Normal evidence | Fault clue |
|---|---|---|
| Single diode | One-way conduction, reverse blocking. | Short both ways or open both ways. |
| Dual diode module | Both internal diode paths show similar readings. | One path differs from the other. |
| Three-phase bridge | Six diode paths between AC input and DC output are consistent. | Any short/open path can cause breaker trip or no DC bus. |
| Output rectifier module | Directional diode behavior remains consistent after leads are disconnected. | Shorted output diode can drag down arc voltage or destroy IGBTs. |
Repair warning
Always disconnect leads before measuring bridge modules. Other connected capacitors, boards and transformer windings can create false meter readings.