Siemens alarm F30043: Power unit: Overvolt 24 V
SINAMICS S120 drive fault · SINAMICS S120
What it means
The power-unit supply voltage rose above the upper monitoring threshold. Overvoltage on the 24 V electronics rail is commonly caused by an unregulated or misadjusted external PSU or by parallel supplies fighting each other; on servo modules the 48 V channel can also be reported. Check PSU setting and wiring; POWER ON acknowledges.
Likely causes
- external 24 V supply set too high or unregulated
- two supplies connected in parallel without decoupling diodes
- wiring fault feeding another voltage onto the 24 V rail
Triage note: Servo MMs show 'Overvolt 24/48 V'; decode channel/voltage from r0949.
Need the part urgently?
Send us alarm F30043 with your machine details — typical RFQ turnaround is 24–48h.