Scope of this technical record
Evidence package for SJ300 / L300P E01-E04 overcurrent repair, used-board evaluation and output-stage replacement decisions.
Evidence collection around output-stage boards must be performed only by qualified personnel after isolation and discharge verification.
What makes an overcurrent repair request actionable
A message saying 'SJ300 E03' is not enough. An actionable request includes the full type code, voltage class, exact code, event timing, motor and cable evidence, load state, parameter changes, output-stage evidence and previous repair history.
This evidence record is built to prevent two common mistakes: replacing a board when the motor/load path is at fault, and replacing an output module without proving the driver and feedback paths that can destroy the new module.
Evidence package
| Evidence | Why it matters | Decision affected |
|---|---|---|
| Exact E01-E04 timing | Routes constant speed, decel, accel or other state | External route versus board route |
| Motor/cable/load proof | Prevents false drive repair | Field service versus bench repair |
| CT/current feedback evidence | Separates real current from detection error | Control board / sensing repair |
| Gate-driver/output evidence | Prevents repeat module damage | Power-stage repair or replacement |
| Board labels and history | Confirms compatibility and failure cause | Used board or replacement drive |
Field record checklist
- Type code and voltage class
- Fault code and operating state
- External output proof
- Current feedback and gate-drive evidence
- Board labels and prior repair
Technical basis and reference documents
This is an independent editorial technical reference. Original manufacturer documentation remains controlling for installation, repair and commissioning decisions.
Public SJ300 troubleshooting chapter used to confirm E01-E04 overcurrent timing, E09 undervoltage context and trip-history discipline.
Public L300P manual used to confirm E01-E04 overcurrent definitions, trip threshold context and E04 current-transformer / noise / DC-braking boundary.
Reviewed internally for SJ300 5.5 kW and 7.5 kW current-detection, output-stage and gate-drive evidence. Drawing files are not redistributed as public sources.
Linked circuit records
Routes E01-E04 timing through motor/cable/load proof, output terminal evidence, current transformer or current feedback plausibility, noise/harness evidence and the boundary where the drive-side output stage becomes suspect.
Maps the drive-side boundary for persistent E01-E04 faults after motor/cable/load proof: gate-drive command, isolated driver supply, protection feedback, output bridge static evidence and repeat-failure prevention.
Keeps E01-E04 troubleshooting outside the drive until motor wiring, cable condition, terminal box contamination, brake release, shaft freedom and load inertia have been proven.
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