Product Description:

The RD51.1-5N-090-L-DL-FW is a drive controller manufactured by Bosch Rexroth Indramat for the RD 500 Drive Controllers series. It serves as the regulating element between the plant’s three-phase mains and an induction motor, shaping voltage and frequency so that speed and torque match the programmed process profile in automated lines and material-handling cells. This arrangement allows the motor to start smoothly, run at controlled speed, and respond to load changes during normal operation. The unit is suited to variable-speed industrial duties where stable motor control is required across a broad operating range.

This model delivers a nominal output of 90 kW, giving it enough capacity for large pumps, blowers, or conveyor drives. The supply section is a 3 x AC converter that accepts line voltages in the 500 V range, so it fits heavy industrial power systems. Motor regulation relies on U/f curve control, which keeps the voltage-to-frequency ratio constant so standard squirrel-cage motors can maintain magnetic flux without encoder feedback. That control method is well suited to applications that need dependable speed control rather than precise servo positioning. Thermal energy from the power electronics is removed by forced air cooling, and the heat sink layout is arranged for continuous airflow inside the cabinet.

Operation is without a built-in brake chopper, so any dynamic braking resistor must be installed externally when the application returns excess energy during deceleration. The unit is part of generation 1. A NAMUR terminal strip provides discrete I/O and uses 24 V standby power from an external supply to keep the control logic active when the main bus is off. For long motor leads, the unit supports cable damping feedback (C3, D3) to reduce reflected waves and minimize dv/dt stress on motor insulation. This helps protect the motor connection over extended cable runs.