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ErrorLib — Industrial Fault Code Library

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dv7

Polarity Judge Timeout

Yaskawa · GA500 Maintenance and Troubleshooting

What does dv7 mean?

The drive failed to detect motor polarity within the preset time, indicating an issue with the motor's electrical connection or winding integrity. This can prevent proper motor startup, accurate current control, and safe operation.

Common Causes

  • Open phase or high resistance in one or more motor windings (U, V, W).
  • Motor cable disconnection or poor terminal contact at either the drive (U, V, W output) or the motor.
  • Incorrect motor wiring configuration (e.g., Delta/Wye) not matching the motor's operating voltage.
  • Internal short circuit or ground fault within the motor windings.
  • Incorrect motor auto-tuning parameter (e.g., L3-01 [Motor Auto-tuning Select]) preventing successful polarity detection.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    1. Power down the drive, disconnect motor cables (U, V, W) from the drive.

  2. 2

    2. Measure resistance between motor terminals U-V, V-W, and W-U; readings should be balanced (e.g., within 5%).

  3. 3

    3. Measure insulation resistance from each motor terminal (U, V, W) to motor frame ground using a megohmmeter (e.g., 500VDC).

  4. 4

    4. Verify all motor cable connections at both the drive and motor are tight and clean.

  5. 5

    5. Ensure the motor is not mechanically locked or excessively stiff, preventing rotation during the polarity test.

  6. 6

    6. Confirm motor type parameters (e.g., P2-04 [Motor Rated Power], P2-06 [Motor Poles]) are set correctly before attempting auto-tuning.

Browse all codes in this manual (60)
Verified technical data. Last updated: April 2026

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Source: Yaskawa GA500 Maintenance and Troubleshooting
View Official PDFSearch more codes in this manual