65289

Motor phase missing

Lenze · i550 Protec Drive

What does 65289 mean?

A failure of several motor phases has been detected. This indicates an open circuit in the motor power cabling or motor windings, leading to imbalanced operation or a complete stop. The error can only be reset after a 2-second blocking time.

Common Causes

  • Open circuit in one or more motor power phases (U, V, W) due to a loose connection at the drive output or motor terminals.
  • Blown fuse or tripped circuit breaker in one phase of the motor power circuit.
  • Internal open circuit in the motor windings (e.g., phase-to-phase break, coil damage) leading to a missing phase.
  • Damaged motor contactor or solid-state relay failing to conduct one or more phases to the motor.
  • Severe imbalance in motor phases due to mechanical damage or excessive load causing current asymmetry.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Disconnect power from the drive and motor, then measure the resistance between all motor phases (U-V, V-W, W-U) at the motor terminal box.

  2. 2

    Measure the resistance of each motor phase conductor from the drive output terminals to the motor terminal box to check for cable continuity.

  3. 3

    Inspect all power connections at the drive's output terminals (U, V, W) and the motor's terminal box for looseness, corrosion, or signs of overheating.

  4. 4

    Check for blown fuses or tripped circuit breakers in the motor power circuit, replacing or resetting as necessary.

  5. 5

    Test the operation of any motor contactors or disconnect switches in the power path to ensure all phases are closing correctly.

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Verified technical data. Last updated: March 2026

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