Product Description:

The RD51.1-4N-075-L-NN-FW drive controller is produced by Bosch Rexroth Indramat within the RD 500 Drive Controllers series. Designed for cabinet installation in automated plants, the unit converts three-phase line power into a regulated AC output for induction motor operation in conveyors, pumps, and general machinery. By modulating voltage and frequency, it acts as an adjustable-speed interface between the mains supply and the mechanical load in industrial automation lines. This allows the connected motor to follow process speed requirements more smoothly during startup and routine operation.

The controller has a rated output of 75 kW, giving it the capacity to run medium-size production motors without derating. It is engineered for incoming line voltages from 380 to 480 V and accepts fluctuations within a ±10 % window, so operation remains stable on industrial power systems with moderate variation. The supply side uses Converter 3 × AC topology, which means the unit rectifies the incoming three-phase supply before inverting it to a variable-frequency output. Motor excitation follows U/f curve control, which links output voltage to frequency and suits constant-torque applications where sensorless operation is acceptable. No additional application functions are preinstalled, so the controller can be configured for the intended motor task.

Thermal management relies on forced air cooling, so airflow paths must remain unobstructed to remove heat from the power stage continuously. An integrated mains filter is included, helping reduce conducted interference without requiring a separate line filter in many installations. The drive is supplied without a built-in brake chopper, so braking energy must be handled by an external resistor module when the application includes frequent deceleration or overhauling loads. The unit is part of design generation 1. With no optional function modules installed, the internal card area remains available for later expansion if the application changes.