What it is and what it does
The Siemens 4EP3904-8DB00-0A is a three-phase mains choke (Netzdrossel) rated for 500 V AC at 50 Hz, with a rated current of 1 A and a maximum current of 1.15 A. Its 0.8 H inductance smooths line-side harmonics and limits inrush current on drives or converters — a standard line-reactor job for a 3-phase input. Open-frame IP00 construction mounts inside a panel or enclosure. Coil loss is 42 W and iron-core loss is 4.7 W at rated load. Thermal class B per IEC 60085 means the insulation system handles a 130 °C hot-spot limit — adequate for a 50 °C ambient with natural convection, but if your cabinet runs hotter, derate or add forced air.
Mounting and connections
Dimensions: 0.219 m wide, 0.179 m high, 0.123 m deep. The screw-type and tab terminals on the main current circuit accept standard ring or fork lugs — no special crimp tool needed. IP00 means no built-in protection against dust or moisture; plan for panel-level sealing if the environment is dirty or humid.