RyF Relay / Contactor Fault fault in delta drive

RyF Relay / Contactor Fault fault in delta drive troubleshooting

Description

RyF is a hardware diagnosis fault. Large VFDs use a "Soft Charge" circuit. When power is applied, current flows through a resistor to charge capacitors slowly. Once charged, a main relay or contactor closes to bypass the resistor. RyF indicates this bypass relay failed to close or the contacts are damaged.

Causes

1. Internal Relay Failure: The coil of the internal bypass contactor is burnt, or the mechanism is stuck mechanically.
2. Low Input Voltage: The voltage is too low to energize the relay coil effectively.
3. Vibration: Excessive vibration has caused the relay contacts to chatter or the connector on the power board to loosen.
4. Resistor Open: The soft-charge resistor is blown, preventing the DC bus from reaching the voltage required to trigger the relay.

Solution

This often requires repair:
1. Listen: Power cycle the drive. Listen for a distinct "Click" or "Clunk" sound about 2-3 seconds after power is applied. No click usually means RyF will follow.
2. Check Input Voltage: Ensure input voltage is within spec. Low voltage makes the relay weak.
3. Tap Test: Sometimes (rarely), a gentle tap on the side of the drive can free a stuck relay, but this is temporary.
4. Repair: If the input voltage is good, the drive power board needs component replacement (relay or resistor).