IndustrialDriveDataDrive Board & Diagnostic Database
DC bus, braking chopper and regeneration-energy boundary

VFD DC Link and Braking Stage

Generic DC-link record for overvoltage and deceleration faults where load inertia, ramp time, braking resistor selection, chopper hardware and input supply conditions must be separated.

Record facts

Key symptomDC bus overvoltage during stop, deceleration or overhauling load
Machine factorHigh inertia, vertical load, winder, fan coast-down or regenerative process
Hardware factorBrake resistor, braking transistor/chopper, DC-link feedback or capacitor condition
Parameter factorRamp-down time, overvoltage stall, braking enable and stop mode

Service notes

  • Do not shorten deceleration time until braking capacity is known.
  • A brake resistor can be open, disconnected, undersized or disabled by parameter configuration.
  • On regenerative or common-DC-bus systems, overvoltage may be a system-energy management problem rather than a single drive board fault.

Related technical records

DC BUS OV
DC bus overvoltage during deceleration

The drive runs normally but trips on overvoltage when stopping, ramping down, lowering a load or decelerating a high-inertia machine.

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VFD input rectifier, precharge and DC-link path

Routes incoming three-phase supply through protection, rectification, precharge and DC-link storage before the inverter stage is allowed to run.

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VFD braking chopper and DC-bus discharge path

Routes excess DC-link energy into braking hardware or controlled overvoltage management during deceleration and overhauling-load events.

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VFD DC-bus overvoltage during deceleration workflow

Drive trips on DC bus overvoltage when stopping, lowering, braking or reducing speed.

Open →