2340 Short Circuit Fault in ABB ACS800 Drive

2340 Short Circuit in the ABB ACS800 Drive indicates that the drive has detected a short circuit at the motor output, typically in the motor cable or motor windings. The ACS800 continuously monitors the output current, and if it detects an abnormally high current caused by a short circuit, it immediately generates Fault 2340 and shuts down the inverter to protect the IGBTs and other power electronics from damage.

This fault generally indicates a problem with the motor, motor cable, or external components connected to the motor output, rather than an internal control fault.

Possible Causes

• Short circuit in the motor windings.
• Short circuit in the motor cable.
• Damaged motor cable insulation.
• Motor cable crushed or pinched.
• Loose or damaged motor terminals.
• Moisture inside the motor terminal box.
• Motor winding insulation failure.
• Phase-to-phase short circuit.
• Phase-to-ground short circuit.
• Power factor correction capacitors connected between the drive and motor.
• Surge absorbers installed on the motor cable.
• Incorrect motor wiring.
• Damaged output terminals.
• Internal inverter output stage failure.
• Defective output IGBT module.

Solutions

• Cycle power to the drive and check whether the fault clears.
• Inspect the motor cable for physical damage.
• Check the motor cable insulation.
• Verify all motor terminal connections are secure.
• Measure the motor winding resistance.
• Perform an insulation resistance (Megger) test on the motor and motor cable.
• Inspect the motor terminal box for moisture or contamination.
• Check for phase-to-phase or phase-to-ground faults.
• Remove any power factor correction capacitors connected between the drive and the motor.
• Remove any surge absorbers installed on the motor cable.
• Verify the motor wiring is correct.
• Inspect the drive output terminals for damage.
• Check the inverter output stage if no external fault is found.
• Replace damaged motor, motor cable, or inverter components if necessary.
• Contact ABB technical support if the fault persists after inspection.

Additional Information

The ABB ACS800 provides fast electronic protection against output short circuits to prevent catastrophic damage to the inverter power semiconductors.

Fault 2340 is generated when the drive detects an abnormally high output current caused by a short circuit in the motor circuit. ABB specifically recommends checking:

• The motor.
• The motor cable.
• That no power factor correction capacitors are installed between the drive and the motor.
• That no surge absorbers are connected to the motor cable.

Power factor correction capacitors and surge absorbers must not be connected between a variable frequency drive and the motor because they can create excessive current, switching transients, and false short-circuit detection, potentially damaging the drive.

Common causes include:

• Damaged motor insulation.
• Crushed or deteriorated motor cables.
• Moisture inside the motor.
• Incorrect motor wiring.
• Internal output stage failure.

Unlike an Overcurrent Fault, which may result from excessive load or rapid acceleration, Fault 2340 is specifically associated with an electrical short circuit on the drive output.

Common Symptoms

• Drive trips with Fault 2340.
• Motor fails to start.
• Fault occurs immediately after the Start command.
• High output current before shutdown.
• Circuit breaker or fuses may trip.
• Motor cable shows signs of damage.
• Burning smell from the motor or cable.
• Drive remains in fault state after reset.
• Motor does not rotate.
• Production process is interrupted.

Recommended Troubleshooting Sequence

1. Disconnect power from the drive.
2. Inspect the motor cable for physical damage.
3. Check all motor terminal connections.
4. Measure motor winding resistance.
5. Perform an insulation resistance test on the motor and cable.
6. Inspect the motor terminal box for moisture.
7. Check for phase-to-phase and phase-to-ground shorts.
8. Remove any power factor correction capacitors from the motor circuit.
9. Remove any surge absorbers connected to the motor cable.
10. Verify correct motor wiring.
11. Inspect the drive output terminals.
12. Test the inverter output stage if the external circuit is normal.
13. Replace defective components if necessary.
14. Restart the drive and verify normal operation.
15. Contact ABB technical support if the fault persists.

Short Circuit Check Table

Check Point	Action
Power off	Disconnect the drive before inspection
Motor cable	Inspect for cuts, crushing, or insulation damage
Motor terminals	Tighten and inspect all connections
Motor winding resistance	Measure all three phases
Insulation resistance	Perform a Megger test on the motor and cable
Motor terminal box	Check for moisture or contamination
Phase-to-phase fault	Inspect for short circuits
Phase-to-ground fault	Test insulation to ground
Power factor correction capacitors	Remove if installed between the drive and motor
Surge absorbers	Remove if connected to the motor cable
Drive output terminals	Inspect for damage
ABB technical support	Contact if the fault remains after inspection

Preventive Maintenance Tips

• Inspect motor cables regularly for mechanical damage and insulation wear.
• Perform periodic insulation resistance testing on motors and motor cables.
• Keep motor terminal boxes clean, dry, and securely sealed.
• Tighten motor and drive output terminals during scheduled maintenance.
• Never install power factor correction capacitors between the drive and the motor.
• Do not connect surge absorbers directly to the motor output cable unless specifically approved by ABB.
• Route motor cables to prevent crushing, abrasion, or moisture ingress.
• Replace damaged motor cables immediately.
• Monitor motor insulation condition as part of predictive maintenance.
• Record recurring short-circuit faults to assist long-term diagnostics.

Proper inspection of the motor, motor cable, and output wiring, routine insulation testing, and ensuring that power factor correction capacitors and surge absorbers are not installed between the drive and the motor will help prevent recurring 2340 Short Circuit faults in ABB ACS800 drives, ensuring reliable inverter protection, safe motor operation, and dependable long-term performance of the drive system.