Siemens · SINAMICS G120
A critical hardware fault has occurred within the inverter's power stack, likely due to a short circuit in an IGBT or the chopper circuit, leading to excessive DC-link current. This indicates severe internal damage to the inverter power components and requires replacement to prevent further system failure and potential safety risks.
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De-energize the drive and wait for DC-link voltage to discharge (e.g., below 50VDC), then perform a diode test on the drive's IGBTs using a multimeter (e.g., between DC+ and output phases U, V, W).
Inspect the DC-link capacitors for physical damage, bulging, or leakage, which may indicate failure.
If a braking resistor is connected, disconnect it and measure its resistance (e.g., using an ohmmeter) to ensure it is within specified limits and not shorted.
Visually inspect the power stack for any signs of burnt components, arcing, or discoloration.
Verify the drive's cooling system (fans, heatsinks) is operational and free from obstruction to prevent thermal stress on power components.