Code PF: Input Phase Loss
Issue Description & Safety Warning
The Yaskawa A1000 AC Drive has triggered a critical Input Phase Loss alarm. Immediate attention from a qualified operator or maintenance technician is required to prevent secondary damage to the equipment or spoiled parts during the manufacturing cycle. Always ensure standard safety and LOTO procedures are followed before accessing electrical cabinets.
Official Troubleshooting Steps
Code type: Fault Manual section: Yaskawa A1000 Troubleshooting There is phase loss in the drive input power. - Check for wiring errors in the main circuit drive input power. - Correct the wiring. There is loose wiring in the drive input power terminals. - Ensure the terminals are tightened properly. - Apply the tightening torque as specified in this manual. Refer to Wire Gauges and Tightening Torque on page 76 There is excessive fluctuation in the drive input power voltage. - Check the voltage from the drive input power. - Review the possible solutions for stabilizing the drive input power. There is poor balance between voltage phases. - Stabilize drive input power or disable phase loss detection. The main circuit capacitors are worn. - Check the maintenance time for the capacitors (U4-05). - Replace the main capacitor(s) if U4-05 is greater than 90%. For instructions on replacing the capacitor(s), contact Yaskawa or your nearest sales representative. Check for anything problems with the drive input power. If drive input power appears normal but the alarm continues to occur, replace either the control board or the entire drive. For instructions on replacing the control board, contact Yaskawa or your nearest sales representative.
Source: Yaskawa AC Drive A1000 High Performance Vector Control Drive Technical Manual (SIEP C710616 21H)
Last reviewed: 2026-07-01 · Verified against the manufacturer’s official documentation.
About Yaskawa A1000 AC Drive Alarms
Yaskawa controllers include extensive self-diagnostics that flag or halt the machine when a fault is detected. Error code PF on the A1000 AC Drive identifies one specific fault condition — its documented cause and the official corrective steps are listed above, sourced from Yaskawa's service documentation. Always confirm against the manual for your exact machine configuration and follow LOTO procedures before servicing.
Complete Alarm List: 280 Yaskawa A1000 AC Drive codes.
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