Rexroth F2077: Rexroth IndraDrive HCS Error Code F2077

Symptoms

Overcurrent alarm during drive enable. The drive trips with overcurrent immediately when the power stage is enabled, before any motion command is issued.

Possible Causes

IGBT power module short circuit (most common cause)
Motor winding short circuit between phases or to ground
Output cable short circuit at drive terminals or motor junction box
Current measurement circuit (Hall sensor) failure giving false overcurrent reading

Troubleshooting Steps

Step 1: Disconnect motor cables (U, V, W) and enable the drive without motor
If F2077 clears without motor, the fault is in motor or cable
Step 2: Megger test the motor: phase-to-phase and phase-to-ground insulation
Insulation resistance > 1MOhm; phase resistance balanced within 5%
Step 3: Check output cables for shorts between phases and to ground
No continuity between phases or to ground
Step 4: If motor and cable are good, the drive IGBT module is shorted and must be replaced
Replacement drive enables without overcurrent

How to Reset

1) Power off. 2) Disconnect motor cables. 3) Enable drive without motor. 4) If fault clears, test motor/cable. 5) If fault persists, replace drive. Caution: Never reconnect a shorted motor to a replacement drive.

Common Replacement Parts

R911319000: IndraDrive power module (verify model) (IGBT module replacement requires factory service)

Frequently Asked Questions

Q: What is the difference between F2077 and F8060?
F2077 typically triggers during drive enable (before motion), while F8060 can trigger during operation. Both indicate overcurrent but at different stages. The diagnostic approach is the same.
Q: Can a Hall sensor cause false overcurrent?
Yes. If the current measurement Hall sensor is damaged, it may report overcurrent even when the actual current is normal. This is diagnosed by testing the drive without motor connected.

Rexroth IndraDrive HCS Error Code F2077