Short circuit

What does ALARM 16 mean?

There is a short circuit condition present in the motor or its wiring. This is a critical fault that can lead to immediate damage of the frequency converter's output stage if not quickly resolved.

• Motor phase-to-phase short circuit due to winding insulation breakdown.
• Motor phase-to-ground short circuit from moisture ingress or insulation degradation.
• Motor cable insulation failure between phases or to ground (e.g., due to chafing or mechanical damage).
• Water or conductive debris in motor terminal box causing short circuit.
• Faulty frequency converter output IGBT leading to a detected short circuit (less common).

Click steps to track your progress.

1. 1

   Disconnect main power supply to the frequency converter at the upstream breaker. Verify zero voltage at L1, L2, L3 terminals.

2. 2

   Disconnect the motor cables (U, V, W) from the frequency converter output terminals (T1, T2, T3).

3. 3

   Measure insulation resistance between motor phases (U-V, V-W, W-U) and from each phase to motor frame ground using a megohmmeter (500VDC).

4. 4

   Measure continuity and insulation resistance of the motor cables from drive terminals to motor terminals.

5. 5

   Visually inspect motor cables for signs of physical damage, chafing, or signs of overheating along their entire length.

6. 6

   If motor or cable insulation resistance is below 1 Megohm, isolate and replace the faulty component.