The following capacitor reform process is recommended for the annual conditioning of power capacitors on VFDs being stored as "spare parts."
The following procedure should be performed at least once every 12-14 months if the VFD has not had power applied in that amount of time:
1) With A.C. power turned OFF, connect 3-phase power supply to the line inputs on the VFD.
2) Turn A.C. voltage supply ON. The VFD should run through its normal "Boot-Up" display, and finish at the "rOFF" or "cOFF" readout.
3) Leave the VFD powered on for a period of at least 60 minutes.
4) Turn A.C. voltage supply OFF. WARNING: Do not disconnect drive wiring until the bus charge lamp is out.
5) Disconnect power wiring.
If the VFD has been left unpowered for a period beyond 14 months:
1) Provide means to supply the VFD power terminals with approximately 115VAC (single-phase is okay) for a period of 30 minutes. The display will readout F4 (low voltage), which is normal.
2) Increase voltage supplied to the VFD up to approximately 230VAC for a period of 30 minutes (or 60 minutes if the VFD is rated for 208-230V only).
3) Increase voltage supplied to the VFD up to 460VAC (or full voltage rating of unit) for a period of 60 minutes.
4) Turn A.C. voltage supply OFF. WARNING: Do not disconnect drive wiring until the bus charge lamp is out.
5) Disconnect power wiring.