Product Description:

The RD51.1-4B-004-L-NN-NN-NN-FW is a drive controller manufactured by Bosch Rexroth Indramat for the RD 500 Drive Controllers series. It is intended to modulate the voltage and frequency supplied to standard induction motors so that machine speed can be matched to process demands without adding external gearbox stages. Within automated conveyors, mixers, or pump skids, the controller serves as the power conversion stage and provides basic motor protection while remaining compatible with common industrial switchgear.

This model is fed from a three-phase mains range of 380 to 480 V. Motor excitation follows a U/f curve control strategy, so the output frequency and voltage remain proportional across the adjustable speed band, giving predictable torque on fan or pump loads. Regenerative energy produced during deceleration is dissipated by the built-in brake chopper, eliminating the need for an external resistor assembly in moderate-inertia applications. Heat produced by the switching devices is removed through forced air cooling, and airflow across the heat sink helps keep semiconductor temperatures within safe limits when the unit is mounted in a control cabinet. Line-side harmonics are attenuated by an integrated mains filter, reducing conducted interference that could affect neighboring equipment.

The supply interface is classified as a converter 3 x AC, which means the device rectifies three-phase input before generating a variable AC output through an inverter bridge. Input variations up to ±10 % from the nominal voltage are tolerated without derating, supporting operation during moderate utility fluctuations. The unit is design generation 1, indicating compatibility with early RD 500 option cards. The controller is not equipped with optional technology functions, so advanced positioning or fieldbus modules must be added externally if those capabilities are required.