What it is and what it does
The Siemens 4EP3604-3DK00 is a three-phase commutating choke (line reactor) designed for converter front-ends. It limits current rise and harmonics on the AC line feeding a variable-frequency drive or DC drive, protecting the converter diodes and smoothing commutation notches. Rated for 9 A continuous (10 A maximum) at 400/480 V AC, 50/60 Hz, with an inductance of 2.9 mH and a relative inductive voltage drop of 4 % at rated current. That 4 % drop is the design target — it tells you the choke will drop about 4 % of line voltage across itself at full load, which is typical for a line reactor sized to limit inrush and harmonic content without excessive voltage loss. Total power loss is 45.4 W (37.6 W in the coil plus 7.8 W in the iron core), dissipated as heat. Thermal class B per IEC 60085 means the insulation system is rated for a 130 °C continuous hot-spot temperature — adequate for most industrial panel environments when mounted with free air circulation.
Mounting and integration
Open-frame IP00 construction — no enclosure, no finger-safe protection. This choke mounts inside a panel or cabinet, not in a wet or dusty location. Dimensions are 148 mm wide, 126 mm tall, 78 mm deep; allow clearance around it for the 45 W heat dissipation. Termination is via screw-type and tab terminals on the main circuit.