The Siemens 3VU2912-4DF0 is a shunt release rated 110/127V AC, designed as a trip accessory for the 3VU2.1, 3VU2.2, and 3VU2.3 motor protection circuit breakers. It provides remote undervoltage or shunt-trip capability, letting a control system or emergency-stop circuit drop the breaker without a manual handle operation.
The release mounts directly into the accessory slot on the front of 3VU2.1, 3VU2.2, or 3VU2.3 frames. No additional wiring harness or adapter plate is needed — the internal trip mechanism couples mechanically to the breaker's toggle latch. Coil voltage is 110/127V AC; verify the control transformer taps match before wiring.