GrF Gravity Fault (Elevator) fault in delta drive

GrF Gravity Fault (Elevator) fault in delta drive troubleshooting

Description

GrF is found in the Delta IED/VFD-ED elevator series. It detects if the motor starts moving in the direction of gravity (down) before the brake releases or before the drive applies torque. It is a "Rollback" protection.

Causes

1. Brake Timing: The brake is opening too early, before the drive has built up enough magnetic flux to hold the car.
2. Low Start Torque: The "Zero Speed Torque" or "DC Injection" level is too low to hold the load.
3. Encoder Phasing: The drive doesn't know which way is up/down correctly.

Solution

Adjust lift timing:
1. Pre-Torque: Increase the "Pre-Torque" gain or "DC Injection at Start".
2. Brake Delay: Increase the "Brake Release Delay". The drive should strain against the brake for a split second before the brake opens.
3. Counterweight: Check if the elevator counterweight is balanced correctly.