Scope of this technical record
Gate-drive and output-stage boundary for SJ300 / L300P E01-E04 cases after motor/cable/load and current-feedback evidence have been separated.
Output-stage work can involve destructive energy and charged capacitors. Do not treat this page as a component-level repair instruction for unqualified users.
Why the driver path is a stop condition
The output bridge does not fail in isolation. A gate-driver channel, isolated driver supply, protection return or current-feedback loop can be the reason a replacement output module fails again. For this reason, the gate-drive path is a stop condition after any repeat E01-E04 or blown-output event.
The page asks for board identity and previous repair evidence because obsolete SJ300 boards can be mismatched by frame or voltage class. The repair path must be tied to installed hardware, not just the family name.
Output-stage acceptance
A credible repair package contains external route proof, static output-stage evidence, driver-channel comparison, feedback route evidence and a controlled validation plan. Without those items, replacement is a gamble.
Field record checklist
- External route cleared
- Driver supply and protection evidence
- Static bridge evidence
- Previous repair 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.
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