Scope of this technical record
Evidence route for SJ300 / L300P E01, E02, E03 and E04 overcurrent trips where operating state, motor/load evidence and current-feedback boundary must be separated before drive-side repair.
Do not repeatedly reset into an overcurrent condition. Isolate the supply, secure the machine and verify DC-link discharge before any output or internal inspection.
The code is the first diagnostic signal
E01, E02, E03 and E04 are not interchangeable. If the panel says E01, the first route is constant-speed load and output short evidence. E02 points to deceleration and braking context. E03 points to acceleration demand and breakaway torque. E04 is the warning that other conditions, DC braking power, current-transformer error or noise may be involved.
That distinction matters for repair planning. A machine with a jammed shaft does not need a power board. A drive with repeat E04 after a board swap may need current-feedback and noise-path evidence before another part is purchased.
Fault-code decision map
| Fault | Common wrong shortcut | Better evidence path |
|---|---|---|
| E01 | Assume IGBT failure | Check motor/cable short, locked shaft and heavy constant-speed load |
| E02 | Assume bad drive during stop | Check decel profile, DC braking power and load inertia |
| E03 | Assume bad current sensor | Check acceleration ramp, torque boost, motor data and load breakaway |
| E04 | Assume random internal fault | Check DC braking setting, CT path, noise, harness and intermittent feedback |
External output route first
The external output route includes U/V/W terminals, cable condition, shield and grounding, the motor terminal box, motor winding connection and the mechanical load. This route must be proven before the case becomes a power-stage repair request.
Dual-voltage motor wiring is important on older installations. A motor reconnected incorrectly can create an overcurrent symptom that looks like a failing inverter, especially during acceleration or first torque production.
When the drive becomes suspect
The drive-side route becomes credible when the external output path is separated and the fault remains. Then the evidence should move to current transformer or current-feedback plausibility, shielding and noise, gate-driver supply, output-stage static evidence and previous repair history.
A repeat overcurrent after module replacement should be treated as a stop condition, not as a reason to fit another module. Driver and feedback paths must be reconciled first.
Field record checklist
- Record exact E01-E04 code and trip timing.
- Document motor/cable/load evidence before internal repair.
- Separate current-feedback evidence from gate-drive evidence.
- Do not approve used-board replacement without frame, voltage class and board labels.
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.
Diagnostic workflow
SJ300 or L300P reports E01, E02, E03 or E04 overcurrent, with the trip tied to constant speed, deceleration, acceleration or another operating condition.
E01-E04 persists after the motor/cable/load route is proven, or the drive has repeated overcurrent after a power-board / output-module repair.
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