Scope of this technical record
Workflow for persistent E01-E04 after external causes are cleared, focusing on current feedback, CT path, noise, gate-drive and output-stage repair boundaries.
Do not energize an output stage with unknown gate-driver, protection feedback or current-sensing condition. Use qualified bench methods only.
From field evidence to board evidence
The workflow intentionally starts after the external route has been cleared. If the motor cable, terminal box, winding connection, brake and load have not been documented, the case is not ready for current-feedback or gate-drive repair.
When the case is ready, the first question is whether the current signal is believable. A false or noise-influenced current signal can produce a repair path very different from a physically shorted output bridge.
Gate-drive stop conditions
Gate-drive evidence matters most after destructive or repeat events. A failed module can damage a driver channel; a weak driver supply or missing protection feedback can destroy the next module. That is why the page treats repeat module replacement as a stop condition until driver and feedback evidence is reconciled.
The output-stage page should therefore collect board labels, static bridge evidence, driver-channel comparison, feedback route and previous repair history before a replacement part is recommended.
Field record checklist
- External output route cleared and documented.
- Current-feedback route photographed or otherwise evidenced.
- Gate-drive supply/protection status recorded by qualified personnel.
- Repair/used-board decision linked to exact frame and board label.
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.
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