The Siemens SIDAC 4EP4083-8DB00 is a 3-phase output reactor rated for 21 A maximum continuous current and a 7200 Hz switching frequency, with an inductance of 0.0011 H. It is designed for AC motor drive output circuits to limit voltage spikes and reduce motor bearing currents, particularly in PWM drive applications where the switching frequency is a key parameter.
What the ratings mean for fit
The 21 A maximum rating defines the continuous current the reactor can carry without exceeding its thermal class B (130 °C) insulation system at a 40 °C ambient. This is the hard ceiling for the motor full-load current on the output side — size the reactor so the drive's rated output current does not exceed this figure. The 7200 Hz switching frequency is the design point for the reactor's core; it will perform correctly at that carrier frequency, but operating significantly above or below may shift the impedance and saturation behavior. The 0.0011 H inductance combined with the 400 V line voltage yields a short-circuit voltage of about 3.13 %, which is typical for output reactors used to limit dV/dt and reflected wave effects on long motor cables.
Where it goes in the panel
This is an IP00 open-frame component — no enclosure, no finger-safe protection. It mounts inside a cabinet. The screw-type terminals accept the motor cable from the drive output and the motor leads. The 0.14 m depth, 0.21 m width, and 0.17 m height mean it occupies roughly the footprint of a small contactor.