Product Description:

The RD51.1-5N-018-L-C1-FW is a drive controller produced by Bosch Rexroth Indramat for the RD 500 Drive Controllers series. It regulates three-phase induction motors in conveyor lines, pumps, and other general machinery by varying output frequency and voltage to match process demand. In an automation system, the unit works as the interface between the incoming line supply and the motor, responding to PLC or operator commands while keeping the control and power sections electrically separated. This arrangement supports adjustable-speed operation in applications that do not require a highly complex feedback-based motor control scheme.

The controller is rated for 18.5 kW of continuous motor power, so it can support motor loads up to that level under normal operation. It connects to a three-phase supply of up to 500 V, and the input uses a 3 x AC converter stage to process the incoming power for variable-frequency output. Motor behavior is managed through U/f curve control, which is a scalar control method suited to constant-torque and quadratic-torque applications where basic speed regulation is sufficient. Heat is removed by forced air cooling, with internal airflow carrying switching and conduction losses away from the heatsink. This cooling method helps the power section maintain stable operation during sustained load conditions.

The controller comes without a built-in brake chopper, so regenerative energy requires an external resistor or another suitable return path. The control electronics accept a dedicated 24 V standby power input, which allows the control section to remain active even when the main power stage is not operating. The unit is in Design Generation 1, matching the first RD 500 design version. It also uses firmware ordered as a separate subposition, so the software package can be selected to fit the intended application.