What it is and what it does
The Siemens 4EP3700-1BP00 is a 3-phase filter reactor rated at 5 kVAR, 400 V, 50 Hz with a 7% p impedance. It's built to EN 61558-2-20, the standard for chokes and reactors. The IP00 enclosure means it's an open-frame component intended for installation inside a panel or cabinet — not for standalone outdoor or washdown duty. Terminals are free conductor ends, so you'll land your own lugs or ferrules.
Where it fits in a drive line
This reactor sits between the supply and a VFD or between the drive and the motor. The 7% p impedance limits harmonic distortion and reduces peak currents on the DC bus.
What the ratings mean for fit
The 5 kVAR rating is the reactive power at rated voltage and frequency — that's the core sizing parameter. The 7% p impedance determines the voltage drop across the reactor at full load; 7% is a typical value for line reactors in industrial drives, providing a good balance between harmonic attenuation and voltage drop. The resonant frequency is 189 Hz, which is well above the 50 Hz fundamental and below typical switching frequencies, so it won't create a parallel resonance with the drive's DC bus capacitors. The 40 °C ambient rating (TA/ISOKL:40 /B) means it's rated for continuous duty at 40 °C ambient with Class B insulation (130 °C rise).