What it is and what it does
The Siemens SIDAC 4EP3806-0CS01 is a three-phase output reactor (output choke) rated for a switching frequency of 4 kHz, with an inductance of 0.9 mH. It's designed to sit between a variable-frequency drive and the motor, smoothing the PWM waveform and limiting voltage spikes that can stress motor windings or cause bearing currents. Rated for a 500 VAC system, the reactor handles a continuous current of 17.5 A at 200 Hz, and 15.8 A at the rated 4 kHz switching frequency. The 0.9 mH inductance and 7% impedance (UK) provide a meaningful dv/dt reduction without excessive voltage drop under load.
Mounting and environment
IP00 rating means this is an open-frame component — no enclosure protection. It's intended for installation inside a cabinet or panel where the environment is controlled. The screw-type terminals accept field wiring directly; plan for adequate clearance around the unit for airflow and heat dissipation. Dimensions are 0.17 m wide, 0.15 m high, and 0.12 m deep. The thermal class F insulation (IEC 60085) allows a 40 °C ambient temperature rating, with copper and iron losses totalling about 45 W (28.9 W coil + 15.9 W iron core). Mount it with some breathing room — it will run warm.