Scope of this technical record
Generic DC-link, regeneration and braking-stage orientation for overvoltage trips during deceleration, stop, lowering, unwinding and other overhauling load states.
DC-link capacitors and brake resistors may be energized or hot after the drive has stopped. Use rated components and OEM braking instructions.
A deceleration overvoltage is usually an energy-routing problem
When a motor is forced to slow a high-inertia or overhauling load, it can return energy to the DC link. The drive must either lengthen the deceleration, dissipate that energy in a braking resistor, return it through a regenerative front end, or coordinate it across a common DC bus.
That makes the first service question practical: did the fault disappear when the ramp was extended, is the brake path enabled and intact, does the resistor heat normally, and is the DC-bus feedback credible?
Braking route evidence
Do not jump from overvoltage to capacitor replacement. Capacitors, feedback and boards can matter, but deceleration timing and brake hardware usually determine the first boundary.
Regeneration and braking split
| Evidence | First implication | Escalation point |
|---|---|---|
| Trips only on short decel | Ramp/load inertia | Increase ramp or add braking capacity |
| Brake resistor fitted but cold | Open wiring / disabled chopper | Check resistor path and brake enable |
| Brake resistor overheats | Undersized duty / repeated stop | Review duty cycle and thermal protection |
| Bus reading disagrees with meter | Bus feedback | Inspect divider/measurement path |
| Common DC bus present | System energy exchange | Review other drives and front-end capacity |
Field record checklist
- Load type and stop event
- Decel time and stop mode
- Brake resistor value/wiring
- Chopper or braking unit status
- Common DC bus/regenerative front-end presence
- Measured bus evidence if qualified
Technical basis and reference documents
This is an independent editorial technical reference. Original manufacturer documentation remains controlling for installation, repair and commissioning decisions.
Workflow for DC-bus overvoltage during stop.
Related technical records
The drive runs normally but trips on overvoltage when stopping, ramping down, lowering a load or decelerating a high-inertia machine.
Routes incoming three-phase supply through protection, rectification, precharge and DC-link storage before the inverter stage is allowed to run.
Routes excess DC-link energy into braking hardware or controlled overvoltage management during deceleration and overhauling-load events.
Drive trips on DC bus overvoltage when stopping, lowering, braking or reducing speed.
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