Siemens SINAMICS S120 Repair

Testing Performed

• Power-up test; DC-bus test; power-stage test; encoder/feedback test; communication test; axis enable test; thermal burn-in.

Final Result

The reference repair process restores normal functional operation after the unit passes the defined electrical, communication, motion, or load checks applicable to the equipment.

Common Fault Codes & Causes

• F30001 – Overcurrent: Motor/cable short circuit, ground fault, excessive load, incorrect motor data or power-unit fault.
• F30002 – DC-link overvoltage: High supply voltage, regenerative energy, short deceleration time or braking issue.
• F30003 – DC-link undervoltage: Low/failed mains supply, phase loss, input fuse or supply interruption.
• F30004 – Drive/inverter overtemperature: Cooling fan failure, blocked airflow, high ambient temperature or overload.
• F30005 – Power unit overload I2t: Excessive continuous load, duty cycle too demanding or undersized drive.
• F30011 – Line phase failure: Missing input phase, blown fuse or severe supply imbalance.
• F30015 – Motor cable phase failure: Open motor phase, loose terminal, damaged cable or unstable control.
• F30021 – Ground fault: Motor winding insulation fault, damaged motor cable or power-stage fault.
• F30027 – DC-link precharge timeout: Precharge circuit, contactor/resistor, supply or DC-link issue.
• F30036 – Internal overtemperature: Internal cooling problem, contamination, fan issue or excessive thermal stress.

Preventive Maintenance

• Inspect motor and feedback cables, maintain cabinet cooling, prevent overloads, check grounding, and investigate repeated fault codes before continued operation.