LSU charge failed

What does 7584 mean?

The supply unit (LSU) did not become ready (e.g., main contactor/breaker closing) within the expected timeframe. This indicates a problem with the LSU's pre-charging or readiness sequence. The drive cannot operate without a ready supply unit.

• No incoming AC mains voltage present at the LSU's input terminals (e.g., L1, L2, L3) or one phase is missing.
• Main input contactor (or circuit breaker) for the LSU failed to close or its auxiliary contact did not provide feedback.
• Pre-charging circuit resistors or contactor within the LSU are faulty, preventing the DC link from charging correctly.
• DC link voltage did not reach the minimum threshold within the expected time, possibly due to excessive load or a short circuit.
• Control power supply (e.g., 24VDC) to the LSU's control board is missing or too low, preventing proper control sequence.

Click steps to track your progress.

1. 1

   Verify the incoming AC mains voltage at the LSU's input terminals (e.g., L1, L2, L3) using a multimeter. Ensure all three phases are present and within tolerance.

2. 2

   Check the operational status of the external main contactor or circuit breaker supplying the LSU. Verify its auxiliary contacts are wired correctly to the LSU's control inputs.

3. 3

   With power off, measure the resistance of the pre-charging resistors within the LSU (if accessible) to check for open circuits.

4. 4

   Monitor the DC link voltage (e.g., via diagnostic menu) during the power-up sequence to see if it begins to charge and where it stalls.

5. 5

   Verify the control power supply (e.g., 24VDC) for the LSU's control board at its dedicated input terminals (e.g., X1) using a multimeter.