Spindle Drive 6SN1123-1AA00-0BA0 with TNC370 - IGBT Shorting Issue

Dear Customer,

We understand you're experiencing repeated IGBT module failures on the V phase of your 6SN1123-1AA00-0BA0 spindle drive connected to a TNC370. The fact that two modules failed shortly after replacement, especially during startup, points to a systemic issue beyond just the IGBT itself.

Here's a breakdown of potential causes and recommended actions:

• DC Link Capacitor Issues: A failing DC link capacitor can cause high voltage spikes and current stress, leading to IGBT failure. Check the DC link capacitor for ESR and capacitance.
• Drive Cooling: Insufficient cooling can overheat IGBTs. Verify proper fan operation and heatsink contact.
• Control Wiring/Signals: Inspect control wiring between the TNC370 and the drive for noise or signal interference.
• Motor Cable: Long or unshielded motor cables can introduce voltage spikes.
• Grounding: Improper grounding can cause common-mode currents and IGBT stress. Verify correct grounding.
• Drive Firmware: An outdated or corrupted firmware could be a contributing factor. Consider updating the drive firmware.

Important: Given the repeated failures, continued operation risks further damage. We strongly recommend a thorough investigation by a qualified Siemens service engineer.

For further support, please access the following resources on SiePortal:

• Siemens Industry Support Portal
• Siemens Service Request

Sincerely,
Siemens Self Support