On Feb. 24 while practising a training exercise, the lower resonator trolley unexpectedly experienced a radial drive failure. The trolley did not move in either radial direction (this occurred after approx. 5 minutes in the tank, near the centre post, with FTRF jig installed). The trolley was retrieved from the tank manually for investigation. Upon retrieval and testing on the mockup, the radial drive began to work again.

Investigation consisted of:

• Verifying controls signals reaching motor controller
• Verifying power to motor
• Verifying all connectors and cables intact
• Verifying drive components installed and free of damage (shafts, keys, set screws, etc.)
• Disassembly and inspection of gearbox
• Running the motor for approximately 3 hours with no load to verify no issues

The cause of the issue cannot be found, however it is suspected a thermal shutdown of the motor or motor controller may have occurred, and after a short delay, the circuit was reset back to a functioning state on its own.

In the future prior to using this trolley it is recommended to test run it, with load, in the mockup to verify radial drive functionality.