Product Description:

The RD51.1-4B-090-L-D1-FW is a three-phase AC drive controller manufactured by Bosch Rexroth Indramat and assigned to the RD 500 Drive Controllers series. Installed inside automation cabinets, it receives commands from PLCs and conditions mains power for induction motors that drive conveyors, pumps, and material-handling lines. By adjusting output frequency and voltage, the unit enables precise speed regulation while keeping motor flux constant. This allows the connected motor to follow process demand more closely during acceleration, steady running, and controlled slowing.

The controller employs U/f curve control to keep the voltage-to-frequency ratio steady across the speed range. Its power stage is rated at 90 kW, allowing continuous operation of medium-size motors without derating. An input window of 380 to 480 V feeds the DC bus, and the unit uses a three-phase AC converter topology that produces a PWM output for the inverter section. A built-in brake chopper directs regenerative energy to an external resistor during quick stops, which helps prevent DC-bus overvoltage during deceleration. Thermal energy is removed by forced air cooling, so unobstructed airflow through the heat sink is required. A NAMUR terminal strip simplifies field wiring, and a 24 V standby circuit keeps the control electronics active when the main supply is off.

This model is classified as design generation 1, which matches first-generation option cards used with this drive platform. An integrated mains filter suppresses conducted emissions, eliminating the need for an external RFI stage. The power section tolerates line variations of ±10 % without issuing a fault, helping the drive remain stable when plant voltage fluctuates. These features make the controller suitable for continuous-duty applications where consistent motor speed and orderly stopping behavior are required.