Siemens alarm F30080: Power unit: Current increasing too quickly

What it means

The power unit detected an excessive rate of current rise (di/dt monitor), pointing to a very low-impedance fault path or a control step-response problem. On motors this strongly suggests winding short-circuit or frame fault; on infeeds it appears with heavy charge/discharge currents during line dips or with a missing line reactor. The fault value bit-codes the affected phase U/V/W.

Likely causes

• motor winding short-circuit or ground fault
• motor power cables misconnected, shorted or over maximum length
• missing/incorrectly connected line reactor at the infeed
• poor line supply quality causing large post-dip charging currents
• incorrect controller parameterization; defective power unit

Replacement parts

We supply the following units for this alarm — tested, warranty-backed:

• 6SL3121-… Motor Module (if output stage suspected)

  motor-module · Common cause

  Request a quote →