What it is and what it does
The Siemens 4EP3700-2US00 is a three-phase AC mains choke (line reactor) designed for installation ahead of a frequency converter (Netzdrossel f. FU). It limits harmonic distortion and reduces current spikes on the drive input, which protects both the converter and upstream distribution gear. Rated for a maximum continuous current of 35.5 A at 480 V AC, 50/60 Hz, with a rated operational current of 31.95 A. The inductance is 0.0004 H and the relative inductive voltage drop is 2% at rated current, voltage, and frequency. Total power loss splits between the coil (49.6 W) and the iron core (9.7 W), with thermal class B insulation. The 40 °C ambient rating is the standard reference; derate above that.
Mounting and connection
IP00 protection class means this choke has no enclosure — it must be mounted inside a panel or cabinet that provides the environmental seal. Dimensions are 0.178 m wide, 0.153 m tall, and 0.105 m deep, so it fits a standard backplate footprint with room for screw-terminal access on the main circuit connections. Main circuit connections are screw-type terminals, which accept common lug or ring-terminal wiring. No DIN-rail clip; this is a bolt-down component.