What it is and what it does
The Siemens 4EU2451-2UA00-0A is a three-phase mains choke (line reactor) designed for installation ahead of a variable-frequency drive (VFD). It smooths the input current, limits harmonic distortion, and protects the drive's DC bus from line transients. Rated for 400/480 VAC at 50/60 Hz, it carries a maximum continuous current of 160 A and a rated current of 144 A — the figure you use for sizing against your motor load. The 0.000088 H (88 µH) inductance produces a 2% relative inductive voltage drop at rated current and frequency. That 2% figure is the design target: it's enough to suppress harmonics without dropping excessive voltage across the choke under load.
Mounting and integration
This is an IP00 open-frame choke — no enclosure, no finger-safe covers. It's intended for installation inside a panel where the live bus bars and flat-type terminals are isolated by the cabinet door or a separate barrier. Dimensions are 0.225 m wide, 0.21 m high, and 0.147 m deep; plan your gland plate and DIN-rail layout accordingly, though the choke itself bolts to a mounting plate rather than snapping onto a rail. The main circuit connects via flat-type terminals — expect bus-bar or cable-lug terminations, not spring-cage or screw-clamp. Verify your lug width and bolt size against the terminal opening before panel assembly.
Thermal and insulation class
Rated for a 40 °C ambient, the coil dissipates 120 W at full load. Class H insulation (180 °C rated) gives a generous thermal margin — the choke can run hot without degrading the winding insulation, which matters in a crowded panel where airflow is restricted.