Applicable Systems
GA700
GA500
A1000
V1000
J1000
Symptoms
The drive trips. The digital operator displays POF, indicating a control power loss. The internal control power supply has failed or been interrupted.
Possible Causes
- Internal control power supply hardware failure
- Control power circuit component degradation
- Momentary complete power loss exceeding ride-through capacity
- Internal fuse or protection device opened
Troubleshooting Steps
- Step 1: Check if there was a complete power interruption in the facility
Confirm with facility operations whether a total power loss occurred - Step 2: Verify the input power is stable and present at the drive terminals
Input voltage is present and stable - Step 3: Power cycle the drive completely (remove and restore input power)
Drive powers up normally after a full power cycle - Step 4: If the fault recurs, the internal control power supply needs service
Drive operates normally after internal service
How to Reset
To reset: 1) Power cycle the drive completely. 2) If the fault recurs, contact Yaskawa service. Caution: POF faults that recur after power cycling indicate internal hardware failure requiring professional service.
Frequently Asked Questions
- Q: What is the ride-through capability of Yaskawa drives?
Ride-through is the ability to maintain operation during brief power interruptions. For complete power loss, the drive can typically maintain control for 2-5 seconds using stored energy in the DC bus capacitors. If the interruption exceeds this, POF trips.
- Q: How do I configure the drive response to power loss?
Parameters L2-01 through L2-05 configure the drive's response to power loss. Options include coasting to stop, restarting automatically when power returns, or tripping with a fault. Set these according to your application's safety requirements.
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Source: Yaskawa GA700 Technical Manual, 2023
Category: PLC & VFD
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