Siemens · DAsl Diagnostics and Alarms
The smoothed total of the phase currents (i1 + i2 + i3) exceeds 4% of the maximum power unit current (r0209). This severe condition often indicates a DC link ground fault, which can introduce a DC component into the line currents, potentially damaging or destroying the power unit, line reactor, or line filter. Other causes include uncalibrated current measurement or a defective current measurement in the power unit.
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Disconnect the motor cable from the drive output and measure insulation resistance between motor phases and ground, and phase-to-phase, using a megohmmeter (e.g., 1000V DC).
Isolate sections of the DC link (disconnect motors, braking resistors, other drives) to pinpoint the ground fault location.
Measure insulation resistance of the DC busbar connections (DC+ to ground, DC- to ground) using a megohmmeter.
Check parameter P0209 (Max. power unit current) and P0210 (Rated motor current) to ensure correct scaling.
Verify integrity of current sensors within the infeed unit by comparing readings with an external clamp meter if possible.