7302

ENCODER A<>B

ABB · ACS800

What does 7302 mean?

The phasing of the pulse encoder connected to the ABB ACS800 drive is incorrect; specifically, phase A is connected to the terminal intended for phase B, and vice versa. This results in inverted or incorrect speed and position feedback (3.09 AW 2 bit 4), leading to motor instability or incorrect direction of rotation.

Common Causes

  • Incorrect wiring of pulse encoder phases A and B at the drive's encoder input terminals or the encoder interface module terminals.
  • Accidental swapping of encoder signal wires during installation or maintenance.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Verify the pulse encoder wiring against the ABB ACS800 drive's wiring diagram and the encoder manufacturer's documentation, paying close attention to phase A and B connections.

  2. 2

    Physically interchange the connections of pulse encoder phases A and B at the drive's encoder input terminals (or the interface module, if applicable).

  3. 3

    After re-wiring, perform a motor ID run or utilize the drive's monitoring parameters to check the encoder feedback and confirm correct phasing and motor rotation direction.

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Verified technical data. Last updated: March 2026

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