Main Circuit Error

What does E25. mean?

This fault signifies a critical error occurring within the inverter's main circuit board. It can be caused by significant electrical noise interference or an internal hardware defect. This type of error impacts the fundamental power conversion and control functions of the inverter, typically rendering it inoperable and requiring internal repair or replacement.

• Internal hardware defect or component failure (e.g., IGBT gate driver, DC bus capacitor, current sensor) on the main circuit board.
• Severe voltage transients or spikes on the incoming AC supply exceeding the inverter's surge withstand capability, damaging power components.
• Excessive electromagnetic interference (EMI) coupled into the main circuit board, potentially disrupting sensitive control logic within the power stage.
• Short circuit or ground fault on the output side (motor or motor cabling) causing severe stress on main power components, even if momentary.

Click steps to track your progress.

1. 1

   Disconnect all power to the inverter. Visually inspect the main circuit board for any signs of burnt components, bulging capacitors, or discolored areas.

2. 2

   Use a multimeter to perform a diode check on the IGBT modules (DC bus P to U, V, W and N to U, V, W) for shorts or open circuits.

3. 3

   Verify the incoming AC supply voltage is stable and within the inverter's specified operating range (e.g., 380-480VAC) using a True RMS voltmeter.

4. 4

   Inspect all power wiring connections (input AC, output motor) for secure terminal connections and proper torque according to manufacturer specifications.

5. 5

   Isolate the inverter by disconnecting the motor. Power up the inverter without the motor connected and observe if the fault immediately reoccurs. If it does, the internal main circuit is faulty.