What it is — and what the ratings mean for fit
The Siemens SIDAC 4EM5308-1CB00 is a 1-phase smoothing choke — a DC link reactor — designed to smooth current ripple on DC bus lines in drives, converters, and power supplies. Rated for a maximum DC current of 20 A (18 A rated continuous), it handles the steady-state load without saturating the core. The 690 V insulation voltage means it can sit on a 400–480 VAC rectified DC bus with margin; the 13 mH inductance (0.013 H) gives enough filtering to knock down the switching-frequency ripple from a 6-pulse or 12-pulse rectifier. Total power loss runs 47.9 W (46.8 W coil + 1.1 W iron core), so plan for that heat in a ventilated enclosure — this is an open-frame IP00 part, no enclosure of its own.
Where it lands in a panel
At 151 mm wide × 151 mm high × 129 mm deep, this choke takes up a solid footprint on a mounting plate — not a DIN-rail clip-on. The screw-type and tab terminals accept ring lugs or fork terminals for the main DC circuit. Thermal class B per IEC 60085 means the insulation system is rated for a 130 °C hot-spot; the 40 °C ambient rating is the standard derating baseline. IP00 means no drip shield or finger guard — mount it inside a locked cabinet or behind a panel door.