26000

Check SINAMICS diagnostic buffer

Navigate to HMI → Diagnostics → Drive → select affected axis → read r0945[0-7] fault buffer to identify specific overtemperature fault code (typically F30001-F30008 range).

r0945[0] shows the most recent fault, check all buffer entries for pattern analysis

Verify cooling system operation

Check cabinet fans, motor cooling fan operation, and verify r0035 (inverter temperature) and r0037 (motor temperature) values in SINAMICS Startdrive or HMI drive monitoring.

Allow 30+ minutes cooldown before restart attempts

Inspect motor and cable routing

Check for blocked motor cooling passages, verify motor cable routing away from heat sources, and confirm p0625 (motor overtemperature threshold) parameter setting matches motor specifications.

Clear fault and monitor

After cooling, clear drive faults via HMI → Diagnostics → Drive → Reset or use SINAMICS p0952=1, then monitor temperature values during operation.

Set up r0035/r0037 monitoring in HMI trace to track temperature trends

Check encoder fault codes

Read r0945 buffer for encoder-related faults (F31xxx series), then verify encoder supply voltage at r0722 and encoder signals via r0061 (actual position) in SINAMICS diagnostic screens.

Never disconnect encoder cables while system is powered

Inspect encoder connections

Check encoder cable connections at motor junction box and drive terminals, verify shield grounding, and test cable continuity. Check p0404/p0405 encoder type parameters match installed hardware.

Verify encoder power supply

Measure encoder supply voltage (typically 5V or 15V) at drive terminals, check r0722 for supply monitoring, and verify p0410 encoder supply voltage parameter matches encoder requirements.

Test encoder functionality

Use SINAMICS commissioning tool to monitor encoder signals during manual axis movement, verify r0061 changes smoothly, and check for signal noise or dropouts.

Use oscilloscope on encoder A/B signals to check for proper 90° phase relationship and signal quality

Identify overcurrent fault

Check r0945 for overcurrent fault codes (F30002, F30012), then monitor r0027 (actual current) and compare to p0640 (maximum current) settings in SINAMICS parameter list.

r0056 shows peak current values that may have triggered the fault

Check motor and mechanical load

Inspect for mechanical binding, excessive cutting loads, or motor issues. Verify motor nameplate data matches p0307 (motor rated current) and p0305 (motor rated voltage) parameters.

Verify drive sizing and parameters

Confirm drive current rating matches application requirements, check p0640 current limit setting is appropriate, and verify p1520/p1521 (current controller parameters) are properly tuned.

Never increase p0640 beyond motor or drive ratings

Test under reduced load

Clear fault with p0952=1, reduce feed rates via NCK feed override, and monitor r0027 during light machining to isolate mechanical vs. electrical causes.

Check DC bus voltage fault

Read r0945 for voltage-related faults (F30003-F30005), monitor r0026 (DC bus voltage) in real-time, and compare to p0210 (line voltage) parameter setting.

r0025 shows line voltage input for comparison with actual supply voltage

Verify input power quality

Measure incoming 3-phase voltage at drive input terminals, check for voltage imbalance >2%, and verify line voltage matches p0210 setting and drive voltage rating.

Inspect DC bus components

Check DC bus capacitors for swelling or leakage, verify brake resistor connections if equipped, and ensure proper grounding of drive chassis and DC bus negative.

DC bus capacitors retain lethal voltage - follow lockout/tagout procedures

Test regenerative braking

If overvoltage during deceleration, check brake resistor operation via r0388, verify p1236 (brake resistor power) matches installed hardware, and test p1240 (brake resistor threshold).

Identify hardware fault code

Check r0945 for hardware-specific faults (F01xxx, F02xxx series), note fault frequency and conditions, and document exact fault code for service support.

Hardware faults often indicate component failure requiring replacement

Verify communication links

Check PROFIBUS/PROFINET communication via r0899 (communication status), verify cable connections to NCK, and test communication parameters p0918/p0979 match NCK configuration.

Perform drive self-test

Use SINAMICS Startdrive commissioning software to run internal diagnostics, check control board LED status indicators, and verify firmware version compatibility with NCK.

Document all LED patterns and fault timestamps for service technician

Contact Siemens support

Hardware faults typically require factory service - document machine serial numbers, drive firmware versions, and complete fault history before contacting technical support.

Do not attempt drive module replacement without proper ESD protection and training