Product Description:

The RD51.1-4N-315-F-NN-FW is a drive controller manufactured by Bosch Rexroth Indramat for the RD 500 Drive Controllers series. It forms the power-conversion link between a three-phase mains supply and an induction motor. The unit provides adjustable voltage and frequency so pumps, fans, and conveyors can follow changing process demands in industrial automation. By changing the output frequency, it lets connected motors ramp smoothly and maintain process speed without direct line operation. This operating principle is typical of variable-frequency drives used in general-purpose motion and process equipment.

At full load, the unit supplies 315 kW of mechanical drive power. It connects to line voltages from 380 to 480 V and tolerates fluctuations of up to ±10 %, which helps it remain in service on industrial grids with moderate instability. That input range fits common plant distribution systems and avoids the need for a dedicated step-down stage in many installations. The unit is a Converter 3 x AC device that uses a rectifier-inverter topology to produce a variable AC waveform suitable for scalar speed control. An integrated mains filter suppresses conducted emissions and supports installation in centralized motor-control centers.

The unit is supplied without built-in brake chopper, so rapid deceleration that returns excess energy requires an external braking resistor. In applications with high inertia or frequent stopping, that returned energy must be handled outside the base unit. Motor excitation uses U/f curve control, where voltage rises in proportion to frequency to maintain air-gap flux across the speed range. Thermal stability is maintained by forced air cooling with integrated liquid circulation, which combines internal airflow with coolant passages to remove heat from the power electronics during continuous operation. Classified as design generation 1, the hardware is delivered without added application functions, and optional functions depend on separately ordered software.