Investigation sequence
Review original failure evidence
Identify whether the first failure was short-circuit, ground fault, overvoltage, cooling, contamination, load or unknown.
Inspect driver hardware
Check gate resistors, driver ICs or optocouplers, clamp/zener parts, desaturation network and isolated driver supplies.
Check DC-link and snubber stress
Inspect capacitors, bus bars, snubber/clamp components and brake chopper for abnormal stress.
Inspect current sensing and protection
A damaged current-feedback path can either false trip or fail to protect the new module.
Verify the external load path
Motor cable, motor insulation, output accessories and mechanical load must be clean before full-load return.
Stop conditions
- Gate driver supply missing
- Any phase-leg gate component is damaged
- External motor/cable fault remains
- No staged test plan is available
Linked records
Repeat module failure usually means the original cause was not limited to the module; gate-drive, isolated supply, current detection, snubber/clamp, motor cable or load evidence must be reviewed.
Immediate overcurrent can be caused by load lock, motor/cable fault, wrong motor data, current-sensing error, gate-driver failure or a damaged output bridge. The trip text alone does not identify the failed component.
The route must separate motor lead, contactor, current sensor, gate-driver command and output power device evidence.
Connects PWM command, isolated driver supply, gate components, short-circuit protection and the output bridge to overcurrent and repeat-module-failure symptoms.
Routes incoming three-phase supply through protection, rectification, precharge and DC-link storage before the inverter stage is allowed to run.