Scope of this technical record
Workflow for GF/earth/leakage trips when the drive output is applied to the motor circuit.
Disconnect the drive before insulation testing according to the OEM procedure. Never megger through connected drive electronics.
Ground-fault workflow route
The workflow keeps insulation testing outside the drive electronics and defines when the drive becomes suspect.
Ground-fault workflow image
Workflow goal
The workflow prevents the common error of treating a GF display as a drive fault before the external output path is proven. It also defines the point where drive-side current/ground sensing becomes the next boundary.
Output insulation sequence
The route starts with timing and environment, then moves through motor/cable accessories and finally sensing electronics.
Ground-fault workflow
| Step | Evidence | Decision |
|---|---|---|
| 1 | Trip only when output is applied | Focus on output path |
| 2 | Moisture/contamination/cable movement | Inspect external boundary |
| 3 | Insulation result with drive disconnected | Confirm motor/cable condition |
| 4 | Output accessories | Review reactor/filter/contactor |
| 5 | Trip remains after permitted isolation | Review drive sensing/output stage |
Field record checklist
- Trip timing
- Weather/washdown history
- Insulation test results with drive disconnected
- Output accessory list
- Cable length and shield
- Result with external path isolated if permitted
Technical basis and reference documents
This is an independent editorial technical reference. Original manufacturer documentation remains controlling for installation, repair and commissioning decisions.
Circuit path for this workflow.
Linked records
The fault boundary includes motor winding insulation, motor cable, output contactor, contaminated terminal box, output filter and current/ground-fault sensing electronics.
Separates motor insulation, cable leakage, terminal contamination, output filters and internal sensing when a drive trips only after output voltage is applied.
Connects PWM command, isolated driver supply, gate components, short-circuit protection and the output bridge to overcurrent and repeat-module-failure symptoms.
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