Scope of this technical record
Workflow for DC-bus overvoltage trips during deceleration, stop, lowering, unwinding or regenerative load events.
Brake and DC-link hardware can be hot and energized. Use rated braking hardware and OEM instructions.
Overvoltage workflow route
The route covers both simple ramp cases and harder brake-chopper or common-DC-bus cases.
Overvoltage workflow image
Workflow goal
The workflow treats overvoltage as an energy-management problem first. It separates ramp/load inertia, brake resistor and chopper operation, DC-bus feedback, incoming supply events and common-DC-bus interaction.
Deceleration evidence sequence
The first useful test is often configuration and timing, not board replacement.
Deceleration overvoltage workflow
| Stage | Evidence | Boundary |
|---|---|---|
| Event timing | Stop/lowering/unwinding/fan coast | Regenerative machine state |
| Ramp settings | Decel time and stop mode | Parameter/energy balance |
| Brake route | Resistor wiring, value, thermal, chopper | Hardware discharge path |
| Bus measurement | Measured vs displayed bus | Feedback path |
| System | Common bus or regenerative front end | Multi-drive energy flow |
Field record checklist
- Machine event
- Decel time
- Brake resistor/chopper evidence
- Bus measurement if qualified
- Common DC bus context
- Drive fault history
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 behind this workflow.
Linked records
The motor is returning energy to the DC link faster than the drive can absorb, dissipate or return it; root cause may be ramp settings, braking hardware, DC-bus feedback or machine load inertia.
Routes excess DC-link energy into braking hardware or controlled overvoltage management during deceleration and overhauling-load events.
Routes incoming three-phase supply through protection, rectification, precharge and DC-link storage before the inverter stage is allowed to run.
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