RD52.1-4B-018-L-NN-NN-T1-FW

The RD52.1-4B-018-L-NN-NN-T1-FW is a drive controller assembled by Bosch Rexroth Indramat for the RD 500 Drive Controllers series. Positioned between the mains supply and an AC motor, the unit modulates output voltage and frequency so production lines can match motor speed to process demand instead of running at fixed grid frequency. In automated conveyors, winders, and pump stations this function reduces energy consumption, limits mechanical stress, and enables programmable acceleration and deceleration profiles that synchronize with sensors and higher-level PLC commands.

During continuous operation with a 4 kHz switching frequency, the drive supplies a rated current of 35 A, translating into a rated apparent output of 23 kVA to the connected machine. When coupled to an induction or synchronous motor, this electrical envelope supports a rated mechanical shaft capability of 18.5 kW. Sustaining these conditions produces internal losses of 0.57 kW, so the controller relies on an external airflow of 0.05 m³/s to evacuate the heat from its power modules and bus capacitors. These baseline ratings define the thermal equilibrium point and establish the limit for application-wide duty-cycle calculations.

Additional headroom is reserved for transient events such as start-up and rapid directional changes. The output stage can draw 70 A for 0.5 s, hold 60 A for 1 s, and still maintain 46 A for a full minute before protective derating is triggered. Within these intervals the inverter reaches an apparent power of 30 kVA, allowing a motor to overcome static friction or momentary load spikes without oversizing the entire drive train. Distinguishing these time-dependent limits from the steady-state figures lets engineers tune overload monitoring, select contactor ratings, and coordinate braking resistor activation to match real process dynamics.