Product Description:

The 21.F4.C3R-3420 is a frequency inverter from KEB belonging to the F4 Combivert Frequency Inverters series. In industrial automation, this device converts fixed-frequency line power into a variable-amplitude, variable-frequency output so that connected motors can be accelerated, decelerated, and held at precise process speeds. Integration of this drive inside control cabinets allows energy use and torque production to be managed without mechanical gear changes, improving throughput in conveyors, pumps, and material-handling axes.

The inverter is designed for a three-phase power connection in the 400 V supply class. Under rated conditions, it draws a nominal input current of 100 A and delivers an output nominal current of 90 A, yielding a continuous apparent power of 62 kVA. An adjustable IGBT bridge operates at a fixed 4 kHz switching frequency to maintain smooth current flow, while overload and short-circuit protection are coordinated with the IP20 housing. Environmental limits follow climatic category 3K3 with permissible relative humidity up to 95% noncondensing. When installation requires reduced electromagnetic emission, the drive supports shielded motor leads up to 50 m and works with a typical 10 Ω braking resistor for controlled deceleration.

To complete the power path, the recommended line cross-section is 50 mm², a dimension selected to limit voltage drop and withstand transient events. Upstream protection must employ a line fuse not exceeding 160 A, while the inverter’s electronic monitor trips at an overcurrent of 162 A and tolerates short-term peaks up to 135 A before timing out. These coordinated thresholds help preserve semiconductor integrity during motor stalls or regenerative surges. The rated motor power that can be controlled is 45 kW, which matches the unit’s continuous-duty capability.