Siemens alarm 300503: Axis %1 drive %2 maximum current monitoring of phase current S (measuring circuit error phase S)
SINUMERIK 840D/810D powerline drive alarm (SIMODRIVE 611D) · SIMODRIVE 611D/611U
What it means
Overcurrent/current-measurement fault detected on phase S of the affected drive.
Likely causes
- short in motor cable (phase S leg)
- motor winding fault
- power-module current sensing/IGBT failure
- coolant ingress into motor connector
Triage note: Flood-coolant machines: inspect motor power connectors for ingress before condemning the module.
Replacement parts
We supply the following units for this alarm — tested, warranty-backed:
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6SN1123-…
SIMODRIVE 611D power module · Primary suspect
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motor per axis nameplate (1FT6/1FT7/1PM…)
motor · Common cause
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6FX5002-…
motor power cable / connector · Common cause
Need the part urgently?
Send us alarm 300503 with your machine details — typical RFQ turnaround is 24–48h.