E000-24401
Rotating Rectifier Diode Set, UCI 274
The rotating rectifier converts the exciter’s AC output to DC for the main rotor field. It consists of six diodes on two heatsink plates plus a surge suppressor. A failed diode causes low or unstable output voltage that closely mimics AVR failure, so both should be checked together.
Fitment
Confirm the frame and winding number against the nameplate before ordering.
| Make | Model / frame | Notes |
|---|---|---|
| Stamford | UCI 274C / 274D / 274E | Confirm winding number |
| Stamford | UCD 274 | — |
Specifications
| Configuration | Six-diode, three-phase full wave |
|---|---|
| Forward current | 40 A per diode |
| Reverse voltage | 1200 V PIV |
| Includes | Surge suppressor (varistor) |
| Frames | UCI 274, UCD 274 |
Cross-references
Equivalent and superseding numbers. Verify against the machine before substituting.
- E000-24402
- RSK 2001
Symptoms that lead here
- Output voltage low and will not respond to AVR trim
- Output hunts with a slow, regular cycle
- Replacement AVR did not resolve the fault
Questions about this part
How do I test a rotating rectifier diode?
Isolate the set and disconnect the diode leads, then test each diode with a multimeter on the diode range. A healthy diode conducts in one direction only. A short-circuit diode reads low resistance both ways; an open-circuit diode reads nothing in either direction.
Should I replace all six diodes or just the failed one?
Replace the complete set. The remaining diodes have seen the same thermal and electrical history, and a partial replacement commonly leads to a repeat failure within months.