Product Description:

The 25.DR.B18-1341 motor input choke is built by KEB for the DR Motor Input Chokes series. This passive component is wired in front of an inverter or motor starter to increase line impedance, damp switching peaks, and limit harmonic distortion. By moderating the steep current edges generated by pulse-width-modulated drives, the choke safeguards drive semiconductors and extends motor insulation life in automated machines that must meet electrical interference limits.

The choke is matched to distribution networks that deliver a maximum of 400 V AC, and its windings carry a continuous line current of 230 A without saturation. An inductance of 0.13 mH provides impedance that filters high-frequency components while keeping the fundamental voltage drop low. Under bolted short-circuit conditions, the unit develops a short-circuit voltage of 4%, indicating its energy storage and the resulting voltage drop across the reactor. Thermal dissipation from copper and core losses reaches 230 W, so cabinet layouts must provide sufficient airflow or heat sinking to keep the coil temperature within insulation limits. The calculated impedance is applied equally across the three legs, allowing the coil stack to maintain phase symmetry during dynamic load changes.

Bus bars sized for a conductor cross-section of 150 mm² fit into the clamp terminals without additional adapters. The laminated core measures 267 mm wide, 335 mm deep, and 230 mm high, giving the choke a compact rectangular footprint for panel installation. Slotted holes on mounting centers of 249 × 113 mm accept 7 × 12 mm mounting hardware for secure fastening when the assembly weighs 31 kg. Three identical windings support the unit’s three-phase configuration and maintain balanced impedance across the connected supply lines. The choke can be mounted upright or horizontally, allowing cables to be routed without bends that are tighter than the conductors permit.