The Siemens 4EM5001-1CB00 is a single-phase commutating choke (line reactor) designed for converter applications — it sits between the AC line and the converter's input rectifier to limit current rise, reduce harmonics, and protect the DC bus capacitors from high dV/dt stress. Rated for 50 A AC maximum at 230 V AC, 50 Hz, with an inductance of 0.28 mH and a relative inductive voltage drop of 2% at rated current — that 2% figure tells you the choke is sized for modest impedance, enough to smooth commutation notches without dropping excessive line voltage. On the DC side it carries 61.2 A, so it handles the higher RMS ripple current typical of a six-pulse rectifier output.
IP00 open-frame construction — no enclosure, no drip shield. This choke mounts inside a cabinet, not on the panel surface. Plan for at least 50 mm clearance around the core for natural convection; the combined copper and iron losses run 41.1 W (13.2 W copper + 27.9 W iron) at rated load, so forced airflow is recommended if the cabinet ambient exceeds 40 °C. Strip length 8 mm. The footprint is 97 mm wide × 128 mm tall × 124 mm deep; it's a standalone component, not DIN-rail mountable, so budget for a sub-panel or chassis-mount bracket.
Thermal class B insulation per IEC 60085 (130 °C continuous) and designed to EN 61558-2-20, the standard for small reactors and chokes. No UL or CSA mark in the evidence, so verify with your local inspector if the panel needs a third-party listing.
The 50 A AC maximum is the thermal current rating (Ith). The 45 A operational AC current (Iln) is the design-point current at which the 2% voltage drop is measured. The 61.2 A DC rating is the current the choke can handle on the DC side when used in a DC-link application — useful if you're repurposing it as a smoothing reactor after the rectifier rather than an AC line reactor.