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ErrorLib — Industrial Fault Code Library

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1

Brake Check Fault

Danfoss · VLT Micro Drive FC 51

What does 1 mean?

This fault indicates an issue during the drive's internal brake check procedure, suggesting a problem with the braking unit or its connection. This could prevent the drive from starting or safely stopping the motor, posing a risk of uncontrolled movement if the braking system is compromised.

Common Causes

  • Mechanical malfunction of the motor brake (e.g., worn pads, seized mechanism) preventing proper release or engagement.
  • Incorrect brake torque setting in drive parameters (e.g., Parameter P2-12 for release time, P2-13 for hold current).
  • Motor brake supply voltage (e.g., 24VDC) outside specified tolerance or intermittent contactor operation.
  • Encoder feedback inconsistency during brake release, causing the drive to misinterpret motor shaft movement.
  • Brake wiring (terminals X1:1, X1:2) short-circuited or open-circuited.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Measure the voltage at the motor brake terminals (e.g., X1:1 and X1:2) when the brake command is active (e.g., 24VDC or 230VAC).

  2. 2

    Inspect the mechanical condition of the motor brake for visible wear, foreign objects, or seizing, applying 24VDC to manually test release.

  3. 3

    Verify the drive parameters related to brake control, specifically P2-12 (Brake release delay) and P2-13 (Brake hold current), adjusting values as per motor data sheet.

  4. 4

    Perform a motor shaft rotation test by hand to confirm free movement after applying power to the brake coil.

  5. 5

    Check continuity of the motor brake wiring from the drive's output terminals to the brake coil using a multimeter.

Browse all codes in this manual (51)
Verified technical data. Last updated: April 2026

Related Faults

00Parameter number does not exist (Register 0007)01No write access to the parameter (Register 0007)02Data value exceeds parameter limits (Register 0007)
Source: Danfoss VLT Micro Drive FC 51
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