Danfoss VLT AutomationDrive FC 302 fault A13: Overcurrent
Alarm 13 on a Danfoss VLT FC 302 is Overcurrent: output current exceeded the inverter peak current limit, approximately 200% of the drive’s rated current. Warning 13 is shown for about 1.5 s, then the drive trips and raises the alarm.
Diagnose this with AI
Try Free Drive Diagnostic Upload a keypad photo, the fault history or a parameter export from your Danfoss VLT AutomationDrive FC 302. InduQT compares the evidence and suggests the next useful checks.
When it happens
- During ramp-up with a high-inertia load
- On shock loading while running
- On ramp-up after a kinetic back-up (mains dip ride-through)
- Instantly at start when the motor or its cable is faulty
Likely causes and checks
1Acceleration too fast for the load inertia
- Points to it
- Trips partway through ramp-up, more often with heavy or high-inertia loads; never at steady speed.
- Check
- Lengthen 3-41 Ramp 1 Ramp Up Time; Danfoss says to choose a ramp that keeps output current below 4-18 Current Limit. Compare the peak current shown on the LCP before and after.
2Shock load or jammed mechanism
- Points to it
- Trips at speed when the load steps, or the motor barely turns before the trip.
- Check
- With power removed and locked out, check that the motor shaft and driven machine turn freely (Danfoss’s first listed check).
3Motor data wrong or motor too large for the drive
- Points to it
- Started after a drive or motor replacement, or after a parameter reset.
- Check
- Check that the motor size matches the drive and that parameters 1-20 to 1-25 match the motor rating plate; run AMA (1-29) if it has not been done.
4Fast ramp-up after kinetic back-up
- Points to it
- Trip follows a supply dip; 14-10 Mains Failure is set to a kinetic back-up option.
- Check
- Read 14-10 and the alarm log times against plant supply events; Danfoss notes a quick ramp-up after kinetic back-up can cause this alarm.
5Short or ground fault in the motor or cable
- Points to it
- Instant trip even unloaded; may alternate with Alarm 14 or Alarm 16.
- Check
- Lock out, wait the discharge time on the nameplate, disconnect the motor cable at the drive, then insulation-test the cable and motor.
Telling it apart
- Timing: partway through the ramp points to ramp time and inertia; the instant the drive starts points to the motor, cable or a seized load.
- Alarm 13 is the hardware peak limit. Warning/Alarm 12 Torque Limit is the softer limit set in 4-16/4-17; Alarm 16 Short Circuit means a short in the motor or wiring; Alarm 14 means current is leaking to ground.
- With extended mechanical brake control selected, Danfoss notes the trip can be reset externally.
Relevant parameters
| Parameter | Name | Why it matters |
|---|---|---|
| 3-41 | Ramp 1 Ramp Up Time | Set so output current stays below 4-18 during the ramp. |
| 4-18 | Current Limit | The limit the ramp-up time is chosen against. |
| 1-20 to 1-25 | Motor data | Must match the motor rating plate. |
| 1-29 | Automatic Motor Adaptation (AMA) | Tunes the drive to the motor. |
| 14-10 | Mains Failure | Kinetic back-up options can lead to A13 on a quick ramp-up afterwards. |
Evidence to collect
- Alarm log (15-30/15-32) with time of the A13
- Output current, speed and what the machine was doing at the trip
- 3-41 ramp-up time and 4-18 current limit
- Motor rating plate vs parameters 1-20 to 1-25
- Insulation test results with the motor disconnected
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