Scope of this technical record
Step-by-step evidence workflow for routing SJ300 / L300P E01-E04 overcurrent by operating status before current-feedback or gate-drive repair.
This workflow is for qualified drive-service personnel. Do not use it to justify repeated resets, live probing or insulation testing through the inverter output.
Workflow overview
The workflow begins with the fault code and operating state, not with a component. A technician should preserve whether the drive was at constant speed, decelerating, accelerating, using DC braking, or exposed to an intermittent event such as contactor noise or vibration.
Once the state is known, the workflow routes the case through external motor/cable/load evidence, then parameter context, then current detection and gate-drive evidence only if the field route is cleared.
Workflow stages
| Stage | Question | Do not proceed if |
|---|---|---|
| Preserve status | Which exact code and operating state? | Fault history has been reset without record |
| External output | Could motor, cable, wiring or load explain it? | Motor/cable isolation is missing |
| Parameter context | Are ramp, boost, motor data or DC braking aggressive? | Machine evidence contradicts parameter assumption |
| Current detection | Does feedback plausibility match the load? | CT/harness/noise evidence is missing |
| Gate-drive | Does the output stage have proven driver/protection evidence? | Prior module failure cause is unknown |
Repair decision boundary
A repair request becomes strong when the workflow creates a coherent path: exact code, external route cleared, parameters reviewed, current-feedback evidence collected and gate-drive boundary identified. Without that path, the safer output is more evidence collection or replacement planning, not board replacement.
Field record checklist
- Record exact E01/E02/E03/E04 code.
- Classify timing before changing parameters.
- Prove motor/cable/load before CT or gate-drive conclusions.
- Capture previous repairs and repeat-failure history.
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 records
E01-E04 are not one generic overcurrent fault. The useful evidence is the operating state at the moment of trip: constant-speed load, deceleration energy, acceleration demand, DC braking or current-detection/noise boundary. The route must prove motor cable, locked shaft, heavy load, wiring, ramp and braking conditions before moving to CT/current feedback, gate drive or output-stage repair.
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.
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.
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