P3 Bus Dip

What does 11315 mean?

The DC bus voltage on port 3 has dipped more than 180V below the drive's bus memory when the drive is offline or in stand-alone mode. This indicates an unstable DC bus voltage, which can affect drive reliability.

• Transient voltage sag in the incoming AC line voltage (Port 3) from the utility grid or plant distribution system.
• Intermittent connection or high resistance at the main input power terminals (R, S, T) for Port 3, causing voltage drops.
• Degradation or failure of DC link capacitors (Port 3), leading to a loss of capacitance and inability to buffer voltage dips.
• Abnormal regenerative energy feedback from an external braking resistor or motor (Port 3) causing bus voltage instability.
• Faulty DC bus voltage sensor or its associated signal conditioning circuit (Port 3) providing an incorrect reading.

Click steps to track your progress.

1. 1

   Use a power quality analyzer to monitor the 3-phase AC input voltage (Port 3) for sags or momentary interruptions.

2. 2

   Inspect and tighten all input power wiring connections at the drive's L1, L2, L3 terminals (Port 3) and upstream devices.

3. 3

   Inspect DC link capacitors (Port 3) for physical defects like bulging, leaking electrolyte, or discoloration.

4. 4

   Verify the integrity and correct connection of any external braking resistors or regenerative units associated with Port 3.

5. 5

   Measure the actual DC bus voltage across the P+ and N- terminals (Port 3) with a multimeter to verify the controller's displayed value.