A Motor Controller’s Components Catch Fire and Melt During Testing of a Fan
Incident Investigation
A Motor Controller’s Components Catch Fire and Melt During Testing of a Fan
July 2, 2021
Reference Number:
II-1224484-2021 (#22816)
Location: Kamloops, BC
Regulated industry sector: Electrical - Low voltage electrical system (30V to 750V)
Incident Overview
Two newly repaired circulation fans were checked/tested by applying power momentarily to confirm proper directional rotation. The east circulation fan was successfully bump tested using the HMI. When it came time to test the west circulation fan, a bump test was unable to be performed using the HMI because of a control and interlock issues. A decision was made to manually bump the west circulation fan motor. The fan motor was bumped twice by pushing in the magnetic starter coil within the MCC with a screwdriver. The magnetic contactor did not properly engage likely causing a single-phase event, the MCC was shut off and a fire extinguisher was used.