What this output reactor does for a VFD line
The Siemens SIDAC 4EP3900-0AS00 is a 3-phase output reactor rated for a maximum continuous current of 22A at a switching frequency of 8 kHz, with an inductance of 0.3 mH per phase. It sits between the variable-frequency drive output and the motor leads, smoothing the PWM waveform and limiting the rate of voltage rise (dV/dt) that can stress motor insulation or cause bearing currents. The 22A rating means it handles motor loads drawing up to that current in continuous duty — sized for a typical 7.5 kW to 11 kW induction motor on a 400 VAC line, depending on the drive's switching pattern and cable length.
Mounting and integration — IP00, screw terminals, panel fit
The screw-type terminals accept field wiring for the main circuit, so no special crimp tooling is needed. Dimensions are 0.21 m wide by 0.17 m tall by 0.12 m deep, which fits a standard sub-panel footprint; plan for a 210 mm width on the mounting plate and allow clearance around the terminals for screwdriver access and cable bending radius.
Thermal design and duty cycle
Total power loss splits between the coil (70 W) and the iron core (11.7 W), summing to roughly 82 W of heat that must be dissipated inside the panel. The reactor is rated for a 40 °C ambient temperature with Class B insulation (130 °C hot-spot limit per IEC 60085). In a sealed cabinet, factor that 82 W into the thermal budget — forced airflow or a larger enclosure may be needed if the panel already runs near its dissipation limit.