4

Breakdown in Braking Unit and/or Braking Resistors

Kone · Frequency Inverter

What does 4 mean?

This error signifies a fault within the regenerative braking unit or its associated braking resistors. This system is crucial for dissipating excess energy generated by the motor during deceleration, and a breakdown can cause DC bus overvoltage.

Common Causes

  • Open circuit or short circuit condition in the braking resistor(s).
  • Malfunction or failure of the braking transistor (chopper) circuit.
  • Overheating of the braking resistors due to continuous or excessive regenerative energy.
  • Faulty wiring or loose connections within the braking circuit.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Visually inspect the braking resistors for any signs of burning, cracking, or physical damage.

  2. 2

    Measure the resistance of the braking resistors; compare the measured value with the specified nominal resistance.

  3. 3

    Verify all electrical connections between the drive, the braking unit, and the braking resistors for security and integrity.

  4. 4

    If possible, check the operation of the braking transistor (chopper) for proper switching.

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Verified technical data. Last updated: March 2026

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