What it is and what it does
The Siemens 4EU3951-6UB00-0A is a three-phase mains choke (line reactor) designed for the input side of a variable-frequency drive. It smooths current harmonics, limits inrush, and provides a degree of protection against line-side transients — the 2 % relative inductive voltage drop at rated current and frequency is the key figure that governs its filtering effect. Rated for 1008 A continuous (1120 A maximum) at 690 V AC, 50 Hz, with an inductance of 0.022 mH. The 540 W coil loss and 190 W iron-core loss at rated conditions give a total self-heating of 730 W — that heat must be managed in the enclosure, especially given the IP00 open-frame construction. Thermal class H (180 °C) insulation per IEC 60085 means the winding can handle sustained hot-spot temperatures up to that class limit, which is typical for drive-duty chokes that see high ambient plus self-heating.
Mounting and integration
The choke measures 0.41 m wide by 0.385 m tall by 0.229 m deep — a substantial footprint. IP00 means it has no enclosure; it must be mounted inside a panel or cabinet that provides the required touch protection and cooling airflow. The flat-type terminals on the main circuit accept busbar or large cable lugs; plan for adequate bending radius and clearance around the connections.