The Siemens 4EU3951-0UB00-0A is a three-phase mains choke (Netzdrossel f. FU) designed for the input side of variable frequency drives. It sits between the supply and the drive's rectifier, limiting current harmonics and reducing voltage notching. A 4% impedance is a common choice for general-purpose drive input filtering — enough to meet IEEE 519-2014 harmonic limits for most six-pulse drives without oversizing the DC bus.
Rated 450 A at 690 V AC, 50 Hz, with a 500 A maximum — this choke is sized for a drive with a nominal input current around 450 A. The 0.101 mH inductance (0.0001 H) is the value that, combined with the 4% drop, gives the harmonic attenuation curve. Power loss splits into 540 W in the copper coil and 198 W in the iron core, totalling 738 W at rated load. That heat must be removed from the enclosure — the IP00 rating means no integral enclosure, so the choke is intended for mounting inside a ventilated cabinet. Ambient temperature rated at 40 °C; above that, derate the current per the manufacturer's thermal curve. The flat-type terminals accept busbar or cable lugs — common for high-current connections in drive panels.
Deployment context
This choke is a panel-mount component — no DIN-rail clip, no IP-rated housing. It bolts into a drive cabinet via its chassis, and the flat terminals connect to the incoming supply busbars and the drive input. The 0.41 m width, 0.385 m height, and 0.229 m depth mean it needs a clear footprint inside the enclosure, with adequate ventilation around the core and coil for the 738 W total heat dissipation.