Product Description:

The RD51.1-4B-200-R-M1-FW is a drive controller produced by Bosch Rexroth Indramat within the RD 500 Drive Controllers series. Industrial automation systems use this unit to regulate induction motor speed and torque through voltage-to-frequency modulation. By combining the power electronics, control logic, and braking circuitry in one enclosure, the device forms a compact link between the plant's three-phase supply and the driven machine. This operating method suits high-power applications where controlled motor speed is needed for continuous process equipment and heavy-duty machine functions.

The unit is rated at 200 kW, allowing it to operate large machinery. It accepts a three-phase AC input of 380 to 480 V, and the permissible supply fluctuation is ±10 %, so the controller can remain stable when line conditions vary within that range. Speed regulation is handled by U/f curve control, which helps maintain approximately constant motor flux across the operating range. That control method is commonly used where dependable speed adjustment is required without a more complex feedback structure. Heat is removed by liquid cooling with an internal pump, and the closed-loop circuit transfers thermal energy to an external heat exchanger instead of the cabinet air. Removing heat through the cooling loop helps reduce the thermal burden inside the enclosure.

Incoming power is conditioned by an integrated mains filter, which reduces conducted electromagnetic noise before it reaches the facility supply. This arrangement also helps limit interference on nearby electrical equipment. Dynamic deceleration is supported by a built-in brake chopper that diverts regenerated energy to external resistors, so no separate braking module is required. The power section is arranged as a 3 × AC converter, which rectifies and re-inverts the grid supply for variable-frequency motor output. The unit is supplied without output chokes, so external reactors are only needed when cable length or dv/dt limits require them. This keeps the base configuration straightforward while still allowing adaptation to the installation layout.