A06250 — Infeed: Defective capacitor(s) in at least one phase of line filter

A06250 tells you that the capacitance of the line filter is no longer what the drive expects: on at least one line phase, the voltages and phase currents measured with a Voltage Sensing Module (VSM) deviate from the capacitance parameterized in p0221. The manuals describe this condition for the infeed of S120 and S150; depending on the drive configuration, the same condition can also be output as a fault or as a message without automatic reaction. The manuals warn: A change or a defect of the line filter capacitors results in a shift of the resonant frequencies and can result in severe damage to the drive system.

• The capacitance of the line filter has changed on at least one line phase.
• The voltages and phase currents that the drive measures at the line filter via the VSM indicate that the filter capacitances no longer match the value parameterized in p0221.

1. Check whether the filter capacitance parameterized in p0221 matches the line filter actually installed.
2. Check the VSM wiring: the differential voltages u12 and u23 must be present at the 100 V/690 V inputs of the VSM, and the phase currents of the line filter must reach the 10 V inputs through a current-voltage transformer.
3. Check in p3676 whether the alarm limit for the permissible filter capacitance deviation is set correctly.
4. Check the scaling of the line supply voltage measurement via the VSM (p3660).
5. Check the scaling of the filter current measurement via the VSM (p3670).
6. Inspect the line filter capacitors; if they prove defective, replace the line filter.
7. With power units connected in parallel: read the average capacitance of all filters in r3677[0...2] and the capacitance of each individual filter in r7320[0...n], r7321[0...n] and r7322[0...n]; the particular VSM identifies the defective filter.

• The drive stores the value in r2124 as a floating-point number: the currently calculated filter capacitance in µF, rounded off to an integer number.
• The first decimal place specifies the number of the phase — 1, 2 or 3 — in which the capacitance deviates from the specified value.

• p0221 — holds the filter capacitance that the drive compares its measurement against; verify that the value matches the installed line filter.
• r2124 — the alarm value of this message: the currently calculated capacitance in µF, rounded off to an integer number, with the phase number in the first decimal place.
• p3676 — the alarm threshold for the permissible filter capacitance deviation; check that this limit is set correctly.
• p3660 — scales the line supply voltage measurement at the VSM; check this scaling when A06250 appears.
• p3670 — gain of the VSM 10 V input for the current transformer; check the filter current measurement scaling with it.
• r3677 — shows the line filter capacitance; with power units connected in parallel, indices 0 to 2 give the average of all filter capacitances.
• r7320, r7321, r7322 — show the capacitance of each individual filter ([0...n]); together with the VSM assignment they localize the defective filter.

This message does not switch the drive off by itself. Rectify the cause first — an incorrect capacitance in p0221, incorrect VSM wiring or scaling, or a genuinely defective filter — and then acknowledge the message. If the drive raises the same condition as a fault, the acknowledgment requires a POWER ON.