Cause : Overspeed- If your Yaskawa GA800 drive is indicating an "Overspeed" fault, it means that the motor is rotating at a speed higher than the maximum allowed by the drive. 

1. There is overshoot.
2. Decrease C5-01 [ASR Proportional Gain 1] and increase C5-02 [ASR Integral Time 1].
3. Adjust the pulse train gain with H6-02 to H6-05 [Pulse Train Input Setting Parameters].
4. There is an incorrect number of PG pulses set in the drive. Set H6-02 [Terminal RP Frequency Scaling] to the pulse train frequency during 100% reference (maximum motor rotation speed).
5. The oS detection level is set incorrectly. Adjust F1-08 [Overspeed Detection Level] and F1-09 [Overspeed Detection Delay Time].
6. If the drive detects the fault at start or in the low speed range (10% or less) and n8-57 = 1 [HFI Overlap Selection = Enabled] for PM Control methods, the high frequency injection gain is too high.
7. Set E5-xx [PM Motor Parameters] correctly or do Rotational Auto-Tuning.
   • Decrease the value of n8-41 [HFI P Gain] in 0.5 unit increments.