Scope of this technical record
Fault-level separation of external motor/cable leakage from drive-side causes for the official Baldor Series 15H HW Ground Fault indication.
Ground-fault work must be performed with output conductors safely isolated. Never apply insulation-test voltage through connected drive electronics and never repeatedly restart into an unresolved fault.
Official meaning and correct first question
According to the official Series 15H manual, HW Ground Fault indicates output-current leakage to ground. The manual's important instruction is not to start by replacing internal hardware: disconnect the wiring between the control and the motor, then determine whether the ground-fault behavior clears. This is a high-value diagnostic boundary.
The question is therefore whether the drive is reacting to the motor/cable installation or whether a drive-side fault remains after the load path is removed. A board-level database should preserve that separation rather than implying that every hardware-labelled fault is an internal circuit-board repair.
Why technicians still need a structured page
Search results for older drives commonly surface manuals and service providers, but the person facing a stopped machine still needs a concise evidence route. Fault timing matters: a fault reported before output enable, immediately at run command or only under load does not carry identical meaning. The connection state at the time of the event must also be recorded.
External causes include motor insulation breakdown, damaged output cable, contamination, incorrect grounding or an application change. Internal causes remain possible once those are excluded: damaged output power devices, sensing/protection circuitry or contamination within the drive. A useful record describes the handoff point between the two investigations.
Isolation logic
| Result after safe output isolation | Likely route | Next evidence |
|---|---|---|
| Fault clears | Motor/cable/installation side | Insulation and cable condition away from drive |
| Fault remains | Drive-side investigation warranted | Output stage, sensing and internal inspection |
| Cannot test safely | Stop and escalate | Qualified service evaluation |
What not to do
Do not megger a motor circuit while it remains connected to the VFD output terminals. Test energy can damage semiconductor or sensing circuitry and turn a diagnosable external problem into an internal repair. Do not repeatedly reset a drive that is detecting a persistent ground path; repeated attempts can aggravate damage in an output stage.
Do not confuse the presence of an auxiliary-power schematic with evidence that a ground-fault event began in the power supply. The reviewed BALDOR 15H supply drawing strengthens the HW Power Supply record, while HW Ground Fault continues to require motor/output-path isolation first.
What a strong repair request contains
The most useful service request includes the complete Series 15H identifier, exact fault string, occurrence timing, motor and cable condition, whether the fault clears with safe output isolation and any evidence of internal damage. This lets a repair provider decide whether the unit needs board evaluation, full power-stage testing or merely confirmation that the external load path caused the trip.
By publishing this distinction, IndustrialDriveData targets a practical gap: not replacing official instructions, but converting fault language into evidence that avoids unnecessary replacement and supports a more accurate technical quotation.
Field record checklist
- Full drive identity
- Exact fault and event timing
- Motor/cable connection state
- Safe external-insulation isolation result
- Any drive-side visual evidence after isolation
Technical basis and reference documents
This is an independent editorial technical reference. Original manufacturer documentation remains controlling for installation, repair and commissioning decisions.
Official source for Series 15H operating scope, fault terminology and first-line troubleshooting guidance.
Public repair-service evidence supporting continuing maintenance demand for the obsolete/legacy family.