Current Unbalance

Hva betyr UnbC ?

The internal current sensor has detected an unbalanced current flow on the motor phases. This could indicate issues with motor wiring, damaged internal power transistors (IGBTs) within the drive, or short-circuits/grounding problems on the connected motor, leading to inefficient operation or potential drive damage.

• One or more motor phases open or having high resistance (e.g., loose terminal, broken wire).
• Motor winding insulation degradation causing phase-to-phase leakage or shorts.
• Damaged IGBTs in one leg of the drive output, resulting in unequal current delivery.
• Unequal impedance in motor cable lengths or cross-sectional areas.
• Poor terminal connections at either the motor or the drive output.

Klikk på steg for å spore fremgangen.

1. 1

   1. Disconnect motor leads (U, V, W) from the drive output terminals.

2. 2

   2. Measure the resistance of each motor winding (U-V, V-W, W-U) using a low-resistance ohmmeter and compare for equality (within 2-5% deviation).

3. 3

   3. Check all motor cable connections at both the drive and motor for tightness, corrosion, or signs of overheating.

4. 4

   4. Measure insulation resistance of each motor phase to ground and between phases using a megohmmeter (e.g., 500VDC).

5. 5

   5. With the motor disconnected, power cycle the drive and check if the fault recurs without a load, indicating an internal drive issue.

6. 6

   6. If the motor and cables are confirmed good, replace the drive unit.