Motor Protection Breaker with ETU550M LSI Trip Unit
The Siemens 3VA2325-5MP32-0DC0 is a 3-pole IEC molded case circuit breaker on a frame 400 platform, purpose-built for motor protection. It carries a breaking capacity class M rating of Icu=55kA at 415 V AC, meaning it can safely interrupt fault currents up to that level without upstream cascading — a key spec for selectivity studies on motor control centers feeding pump, fan, or compressor loads. The ETU550M electronic trip unit provides LSI protection (long-time, short-time, instantaneous) with an adjustable overload pickup IR from 100 A to 250 A, and short-circuit protection ISD adjustable 1.2–15× In. The instantaneous pickup II also spans 3–15× In, giving the engineer room to coordinate with downstream contactors and overload relays.
Integration Notes
The breaker is configured for busbar connection, which simplifies panel layout in a motor control center or distribution board. The built-in undervoltage release (208–230 V AC, 50/60 Hz) provides a clean way to implement emergency-stop or safety-circuit dropouts without an external shunt-trip module. Two auxiliary switch changeover contacts are included for status feedback to a PLC or SCADA system — one less accessory to order separately.