The Siemens 4EU3921-1BA00-0A is a 3-phase commutating choke for converter applications, rated 750 V AC operating voltage and 450 A continuous current (500 A maximum). Its 0.11 mH inductance limits di/dt and reduces harmonic stress on the converter's semiconductors — a critical component for protecting the drive stage in high-power rectifier or inverter circuits.
Power loss splits into 360 W coil loss and 277 W iron-core loss at rated conditions, totalling 637 W. That heat must be managed in the enclosure — the IP00 open-frame design assumes installation in a cabinet with forced airflow or sufficient natural convection, not a sealed box. Thermal class H (180 °C) per IEC 60085 means the insulation system can handle peak hot-spot temperatures up to 180 °C, giving margin for overloads or higher ambient conditions. The 40 °C ambient rating is the baseline; derating applies above that.
Mounting and connection
The main current circuit terminates via flat-type connectors — expect bus-bar or heavy cable lugs, not screw terminals. Physical footprint is 0.41 m wide × 0.385 m high × 0.229 m deep; plan panel layout around those dimensions and the open-frame IP00 mounting.
Designed to EN 61558-2-20 (safety of transformers, reactors, and power supply units — particular requirements for small reactors). The choke is rated for 50 Hz operating frequency, 3-phase AC voltage.