Staring at Fault 2340 on your ABB ACS880? Learn how to identify motor short circuits, check for cabling errors, and resolve internal drive issues with our expert guide.
When an ABB ACS880 industrial drive stops and flashes Fault 2340 (Short Circuit), it is acting on its most critical protective instinct. This fault indicates that the drive has detected a massive surge of current—far beyond normal operating limits—suggesting a direct electrical short circuit between the output phases or to the ground.
Because this fault protects the internal IGBTs (Insulated Gate Bipolar Transistors) from literal destruction, the drive shuts down in microseconds. This guide provides a systematic, human-made approach to finding the short and getting your system back online safely.
Understanding the Root Cause
The 2340 error occurs when the drive’s output current exceeds its instantaneous hardware trip limit. While it sounds catastrophic, the cause is often found in the external cabling or motor rather than the drive itself. Common triggers include:
- Motor Winding Failure: Internal insulation breakdown inside the motor.
- Cable Damage: A nicked or crushed cable where two phases are touching.
- Moisture: Water ingress in the motor terminal box.
- Prohibited Components: Capacitors or surge suppressors installed on the output side.
Step-by-Step Solutions
1. Inspect Motor and Cable for Errors
The most common cause of Fault 2340 is a physical failure in the “field” equipment. Do not skip these checks:
- Visual Check: Inspect the motor terminal box for black soot, moisture, or loose wire strands that could be bridging the phases.
- Cabling Errors: Ensure that phases are not swapped or touching the conduit/ground.
- The Megger Test: Disconnect the motor leads completely from the drive. Use an insulation resistance tester (Megger) on the motor and cables. Check for shorts between phases (U-V, V-W, U-W) and from each phase to ground.
Note: Never Megger the drive terminals! Only Megger the disconnected cables.
2. Remove Prohibited Load-Side Equipment
VFDs output high-frequency PWM (Pulse Width Modulation) signals. Certain electrical components designed for traditional “across-the-line” motors will act as a dead short to a VFD:
- Power Factor Correction Capacitors: These must never be installed between the VFD and the motor. They will cause an immediate 2340 trip.
- Surge Absorbers/Suppressors: These are often found in older motor terminal boxes. They can misinterpret the VFD pulses as voltage spikes and attempt to clamp them, triggering the fault.
Action: If these components are present, remove them and wire the motor directly to the drive.
3. Perform a Power Cycle (Resetting the Logic)
In some rare cases, a transient electrical glitch can “latch” the short-circuit protection logic in the drive’s control unit.
- The Cold Boot: Turn off the main power and any external 24V DC control power.
- Wait for the display to go completely blank.
- Restore power. If the fault was a “ghost” caused by interference, the drive will return to “Ready” status.
Advanced Diagnostic: The Isolation Test
If you have verified that the motor and cables are perfect, but the drive still trips on 2340 the moment you press Start:
- Disconnect the motor cables (U2, V2, W2) from the bottom of the drive entirely.
- Attempt to start the drive (it will likely trip on “Motor Phase Loss,” but that is normal).
- If Fault 2340 still occurs with NO motor connected: The internal power module (IGBT) of the ACS880 is shorted. The drive unit itself is damaged and needs professional repair or replacement.
Summary Checklist
| Checkpoint | Action Required |
|---|---|
| Cabling | Ensure no loose strands are touching the metal casing. |
| Capacitors | Remove any power factor correction devices from the output. |
| Motor Insulation | Megger motor and cable (must be disconnected from VFD). |
| Sizing | Ensure 99.10 (Motor Nominal Power) matches the nameplate. |