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ErrorLib — Industrial Fault Code Library

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Er - 08

Rated Slip Fault

Yaskawa · F7 Drive

What does Er - 08 mean?

This Auto-Tuning fault means the process did not complete within the specified time, or the calculated rated slip value was outside the parameter setting range. It can also occur if the motor rated voltage setting (T1-03) is higher than the Drive's actual input voltage. Incorrect slip data will negatively impact motor speed regulation and torque control.

Common Causes

  • Inaccurate motor rated speed (P2-04) or rated frequency (P2-06) entered, affecting slip calculation.
  • Incorrect number of motor poles (P2-03) specified, which directly impacts synchronous speed and slip.
  • Motor rated voltage (P2-05) setting does not match the actual motor winding voltage.
  • Drive output voltage not reaching motor rated voltage during tuning due to incorrect Drive input voltage or settings.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    1. Verify the motor nameplate data for P2-04 (Motor Rated Speed) and P2-06 (Motor Rated Frequency) is correctly entered.

  2. 2

    2. Confirm parameter P2-03 (Motor Poles) is accurately set based on the motor's nameplate.

  3. 3

    3. Check parameter P2-05 (Motor Rated Voltage) matches the motor's nameplate voltage rating.

  4. 4

    4. Measure the input voltage to the Drive at terminals R/L1, S/L2, T/L3 to ensure it is within the Drive's specified operating range.

  5. 5

    5. Temporarily disable any voltage boost or flux braking features that might interfere with voltage regulation during tuning.

Browse all codes in this manual (63)
Verified technical data. Last updated: April 2026

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Source: Yaskawa F7 Drive
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