Siemens alarm F30061: Bridging contactor monitoring

What it means

The bypass (bridging) contactor that shorts out the pre-charge resistor after DC-link charging did not deliver the expected feedback within p0255[1]. Fault-value bits distinguish switching timeout, opening during operation, and closing while OFF/during pre-charge. A bypass that fails to close leaves the pre-charge resistor permanently in circuit, where it overheats; this monitor prevents that condition from going unnoticed.

Likely causes

• bridging/bypass contactor contacts worn or welded
• feedback signal wiring or auxiliary contact faulty
• p0255[1] monitoring time mismatched to contactor response
• contactor coil driver output defective

Replacement parts

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

• Bypass contactor per infeed rating (Siemens 3RT/3TF series)

  infeed · Common cause

  Request a quote →