Fagor alarm E903: RPS: Phase missing in the power line
DDS drive display code (seven-segment; PS/XPS/RPS power supplies) · Fagor PS/XPS/RPS
What it means
Not all three power phases are reaching the RPS module, so it refuses to start regeneration. Verify the power connections are properly made — check upstream fuses, contactor poles and the L1/L2/L3 terminations. Note the FAULT led blinking (not steady) indicates missing phases without any other error being active.
Likely causes
- blown fuse on one phase upstream
- contactor pole welded open or burnt
- loose lug at RPS power terminals
- utility single-phasing event
Replacement parts
We supply the following units for this alarm — tested, warranty-backed:
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Mains fuses / NH gG per electrical diagram
component · Common cause
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Mains contactor (size per diagram)
component · Check if others ruled out
Need the part urgently?
Send us alarm E903 with your machine details — typical RFQ turnaround is 24–48h.