Over current
Danfoss · VLT HVAC Drive FC 102
What does 13 mean?
The inverter peak current limit (approximately 200% of the rated current) has been exceeded, causing the frequency converter to trip after about 1.5 seconds. This is often caused by shock loading, rapid acceleration with high inertia loads, or can occur after kinetic back-up. Repeated overcurrent can lead to damage to the inverter's power stage.
Common Causes
- Sudden mechanical shock load on the motor shaft, causing an instantaneous current surge exceeding 200% of rated current.
- Output short circuit between motor phases (U, V, W) or a phase-to-ground fault in the motor cable or motor windings.
- Extremely fast acceleration ramp time (P3-41) set without adequate current limiting or torque control.
- Improper motor tuning (e.g., auto-tuning failed or not performed) leading to unstable current control.
Repair Steps & Checklist
Click steps to track your progress.
- 1
Measure the motor output current (U, V, W) with a clamp meter during acceleration or load changes, checking for transient spikes.
- 2
Disconnect the motor cables from the drive's output terminals (U, V, W) and measure the resistance between each phase and to ground to check for short circuits.
- 3
Increase acceleration ramp time in parameter P3-41 (Ramp Up Time 1) to reduce the initial current surge during start-up.
- 4
Perform an auto-tuning procedure (P1-29) if available, ensuring the motor parameters (P1-20 to P1-25) are accurately entered.