Description of Event or Problem · 1
REPORTED PROBLEM: UNIT CAUGHT FIRE DURING PHYSICS TESTING. CARESTREAM¿S INVESTIGATION FOUND THAT THE REPORTED FIRE WAS ACTUAL HIGH ENERGY ELECTRICAL ARCING OCCURRING ON THE GENERATOR¿S INVERTER BOARD. THE HIGH ENERGY ARCING OCCURRED AS A RESULT OF A CATASTROPHIC FAILURE OF TWO FIELD EFFECT TRANSISTORS (FETS) LOCATED ON THE GENERATOR¿S INVERTER BOARD. ONCE THE FETS FAILED, THE SYSTEM BLEW A FUSE INTENDED TO HALT THE FLOW OF ENERGY TO THE DAMAGED BOARD. THE FUSE HOWEVER, BLEW IN A WAY THAT ALLOWED CURRENT TO BYPASS THE FUSE BLOCK THEREBY SUSTAINING THE EVENT. THE EVENT WAS TERMINATED, WHEN THE SYSTEMS CIRCUIT BREAKER WHICH SERVES AS A SECONDARY SAFETY COMPONENT FOR THIS TYPE OF FAILURE WAS MANUALLY SWITCHED OFF. ONCE THE SYSTEMS CIRCUIT BREAKER WAS TURNED OFF, CURRENT FLOW TO THE DAMAGED BOARD HALTED AND THE THERMAL EVENT CAME TO AN END.