Fault Phenomenon: Potain tower crane cannot start after rain; water stains found inside the inverter cabinet, residual current device trips.

Troubleshooting Process:
– Powered off and inspected cabinet: top sealing rubber strip aged and detached.
– Inspected internal components: some circuit boards damp and corroded.
– Dried and replaced damaged circuit boards, re-applied waterproof sealing.

Root Cause: The inverter cabinet top seal failed, allowing rainwater to seep in and cause electrical shorts.

Required Parts: Sealing strip, damaged circuit boards.