What it is and what it does
The Siemens 4EP3700-1BK00 is a three-phase mains choke (line reactor) designed for installation upstream of a variable frequency drive (VFD). Its job is to smooth the input current, reduce harmonic distortion, and limit inrush current spikes that would otherwise stress the drive's rectifier and DC bus capacitors. Rated for a continuous current of 15.6 A with a maximum of 17.3 A, the choke handles the full-load current of a typical 7.5 kW to 11 kW drive on a 480 V three-phase supply. The 1.7 mH inductance delivers a 4 % relative inductive voltage drop at rated conditions — a standard impedance value that balances harmonic mitigation against voltage drop across the choke. The 4 % voltage drop means that at full rated current, the drive sees about 461 V instead of 480 V at its input terminals. That is within the operating window of most industrial drives, but if your drive is already marginal on input voltage (e.g., a 460 V unit on a 480 V line), factor the 4 % drop into your voltage budget.
Key ratings and what they mean for fit
The choke is rated for an operating voltage of 460 V to 480 V AC at 50/60 Hz. That covers the common North American 480 V and international 460 V industrial three-phase supplies. Total power loss is 56.5 W — 46 W in the coil and 10.5 W in the iron core. That heat must be dissipated inside the enclosure. In a sealed IP54 cabinet, that 56.5 W adds to the thermal load; factor it into your ventilation or cooling calculation. Protection class IP00 means the choke has no enclosure — it is an open-frame component intended for mounting inside a panel that provides the environmental protection. The screw-type and tab terminals accept standard ring lugs or fork terminals for the main power connections.
Panel integration notes
The choke measures 0.178 m wide by 0.153 m tall by 0.105 m deep. It is a panel-mount component, not DIN-rail clip-on. Plan for screw-mounting on a backplate with clearance for the screw/tab terminals on top. Because it is IP00, the choke must be mounted inside an enclosure that provides at least finger-safe protection (IP2X or better). Keep at least 50 mm clearance around the choke for airflow to carry away the 56.5 W of heat.