The Siemens 4EU2552-0UB00-0AA0 is a 3-phase mains choke (Netzdrossel f. FU) designed for the input side of variable frequency drives. It reduces harmonic distortion and limits inrush current, protecting the drive's rectifier stage and improving power quality on the line side. Rated at 144 A continuous with a 160 A maximum, it operates at 690 V AC, 50 Hz, and delivers a 2 % relative inductive voltage drop at rated current — the standard impedance for most drive input reactors. Flat-type terminals accept busbar or lug connections for the main circuit.
The 144 A rated current (160 A maximum) matches the continuous input current of a drive sized for a 75–90 kW motor at 400 V, or roughly 110–130 kW at 690 V. The 2 % impedance is the typical value for drive input reactors — high enough to attenuate harmonics, low enough to avoid excessive voltage drop under load. Inductance is 0.00016 H (0.16 mH) per phase, measured at rated current and 50 Hz. This value, combined with the 2 % drop, confirms the reactor is tuned for standard 50 Hz drive applications — not for 60 Hz or for DC-link chokes. The 140 W coil loss plus 44 W iron core loss (184 W total) is the heat that must be ventilated out of the enclosure. Rated ambient temperature is 40 °C. If the panel ambient runs hotter, derate the current or increase airflow — the thermal class H headroom buys some margin, but the 40 °C rating is the design point.
Dimensions: 0.225 m wide × 0.21 m high × 0.176 m deep. This is a compact footprint for a 144 A reactor — roughly the size of a shoebox. It mounts via the flat-type terminals and its own chassis; no DIN-rail clip. Plan for a panel cutout or mounting plate that accommodates the 225 mm width and allows clearance for the flat terminals and ventilation around the 184 W heat dissipation.