Applicable Systems
EFC
FEX
FEI
HNC
Symptoms
Device overload shutdown. The drive has detected prolonged overload condition and has shut down to protect the power module from thermal damage.
Possible Causes
- Continuous operation above rated current for too long
- Insufficient cooling due to blocked airflow or failed fan
- Ambient temperature exceeding drive specification (typically 40C)
- Motor undersized for the mechanical load
Troubleshooting Steps
- Step 1: Check the drive cooling fan operation and airflow path
Fan running; no obstructions in air intake or exhaust - Step 2: Measure ambient temperature inside the control cabinet
Temperature below 40C; if higher, improve ventilation - Step 3: Review the load profile to determine if the motor is undersized
Motor RMS current within rated continuous current - Step 4: If overload is legitimate, upgrade to a larger drive and motor
New drive/motor handles the load without thermal trips
How to Reset
1) Allow drive to cool (wait 10 minutes). 2) Check fan and ventilation. 3) Verify ambient temperature. 4) Review load sizing. 5) Reset and monitor. Caution: Repeated F8057 trips will eventually damage the power module.
Frequently Asked Questions
- Q: How long does the overload protection take to trip?
The drive uses a thermal model (I^2t). Typical trip time: 60s at 150% overload, 3 min at 110% overload, continuous at 100%.
- Q: Can I increase the overload tolerance?
The I^2t parameters can be adjusted within limits, but the motor and drive must be sized for the application. Do not disable thermal protection.
Source: Rexroth IndraDrive HCS/HMS Fault Code List, Bosch Rexroth AG
Category: PLC & VFD