F30081 — Power unit: Switching operations too frequent

F30081 is raised when the power unit has executed too many switching operations for current limitation. The drive tells you through the fault value which output phase was affected. The manuals for S120, S150, G130 and G150 additionally list causes at the infeed and causes that apply only to a parallel switching device; the G120 and G120XA manuals limit the causes to motor, cabling and the power unit itself.

• The power unit has executed too many switching operations for current limitation.
• The closed-loop control is parameterized incorrectly.
• The motor has a short-circuit or a fault to ground (frame).
• U/f operation: the up ramp is set too low.
• U/f operation: the rated current of the motor is much greater than that of the power unit.
• Where the converter includes an infeed (S120, S150, G130, G150): high discharge and post-charging currents after a line voltage dip.
• Infeed: high post-charging currents when the motor is overloaded while motoring and the DC link voltage dips.
• Infeed: short-circuit currents at switch-on because no line reactor (commutating reactor) is fitted.
• The power cables are not correctly connected.
• The power cables exceed the maximum permissible length.
• The power unit is defective.
• Parallel switching device (r0108.15 = 1): a power unit has tripped (switched off) due to a ground fault.
• Parallel switching device (r0108.15 = 1): the closed-loop circulating current control is either too slow or has been set too fast.

1. Check the motor data and, if required, carry out commissioning again.
2. Check the motor circuit configuration (star-delta).
3. In U/f operation, increase the up ramp.
4. In U/f operation, check the assignment of rated currents of motor and power unit.
5. On converters with an infeed (S120, S150, G130, G150): check the line supply quality.
6. Infeed: reduce the motor load.
7. Infeed: correct the connection of the line reactor.
8. Check the power cable connections.
9. Check the power cables for short-circuit or ground fault.
10. Check the length of the power cables.
11. If the fault persists, replace the power unit.
12. With a parallel switching device (r0108.15 = 1): check the ground fault monitoring thresholds (p0287).
13. With a parallel switching device (r0108.15 = 1): check the setting of the closed-loop circulating current control (p7036, p7037).

• The message value carries the fault cause (%1) in binary form; the drive stores it as the fault value r0949.
• Interpret r0949 bitwise binary:
• Bit 0: Phase U.
• Bit 1: Phase V.
• Bit 2: Phase W.

• r0949 — fault value: read it bitwise binary to see whether phase U, V or W signalled the switching operations fault.
• r0108 — bit 15 set to 1 tells you a parallel switching device is configured; only then do the additional ground-fault and circulating-current causes and checks apply.
• p0287 — ground fault monitoring shutdown threshold: check it when, in a parallel switching device, a power unit tripped due to a ground fault.
• p7036 — proportional gain of the circulating current control: check its setting when the closed-loop circulating current control is too slow or has been set too fast.
• p7037 — integral time of the circulating current control: check it together with p7036 for the same cause.

The drive reacts with OFF2, i.e. the power unit coasts down and no restart is possible until the fault is cleared. After working through the checks above, acknowledge the fault IMMEDIATELY and restart the drive; the manuals name no further reset procedure for this code.