Investigation sequence
1
Classify the occurrence
Separate immediate POFF after power-up from POFF appearing under motor operation.
2
Check the drive-board detection area
Inspect the local voltage-sensing path, capacitors and ribbon connection condition.
3
Inspect load-related behavior
For run-only POFF, include the drive-board transformer and stressed supply behavior in the investigation.
4
Prevent repeat damage
Do not repeatedly cycle power or run commands before addressing suspected damaged capacitors or power components.
Stop conditions
- Bulged or vented DC-link capacitor
- Suspected rectifier/IPM damage
- Abnormal DC-bus behavior
Linked records
Evidence intake
Turn this record into a qualified service request
A repair decision is much more reliable when the request includes the exact identity of the drive, the first fault evidence and the machine condition when the symptom appeared.
- Complete drive type code / MLFB or nameplate model
- Fault code, fault value and first event before reset
- When the event appears: power-up, enable, ramp, run, decel or stop
- Motor/cable connected or isolated during the symptom
- Visible board, option-card, module and connector identifiers
- Previous repair history, replacement parts and repeat-failure pattern