What it is and what it does
The Siemens 4EP3801-3DS00 is a 3-phase commutating choke (line reactor) designed for converter front-ends. It limits current rise and harmonics on the AC side of variable-speed drives and rectifiers, protecting the converter diodes and smoothing the DC bus. Rated 40.5 A continuous with a 45 A maximum, it handles 400 V AC at 50 Hz. The 0.62 mH inductance with a 4 % relative inductive voltage drop at rated current gives the filtering performance a drive designer expects from this class of choke.
Key ratings and what they mean for fit
The 40.5 A rated current (I LN) is the continuous thermal rating at 40 °C ambient — the number you size against the drive's input current, not the motor FLA. The 45 A maximum (I thmax) is the short-term overload ceiling; sustained operation at 45 A requires derating. The 0.62 mH inductance at 4 % voltage drop (u k) is the standard impedance for 400 V class drives — it limits DC bus ripple and reduces harmonic distortion to within typical grid-code limits. IP00 means no enclosure protection; the choke must be mounted inside a panel or cabinet with at least IP2x guarding.
Where it goes and how it connects
Mounts on the panel floor or a mounting plate — no DIN rail, this is a bolted-down component. Screw-type terminals for the main circuit accept standard power wiring. The 0.178 m width, 0.153 m height, and 0.12 m depth footprint fits a typical drive cabinet section alongside the input contactor and fuse block. Thermal class B (130 °C) insulation per IEC 60085 means it can run hot without degrading the winding; the 52.8 W coil loss and 19.5 W iron-core loss total about 72 W of heat to vent in the enclosure.
Lifecycle and sourcing reality
Mature lifecycle stage — established, stable design still in the Siemens portfolio. No EOL notice or successor code appears. Sourced to order against an RFQ through independent distribution.