Product Description:

The RD51.1-4B-018-P-NN-FW is a drive controller manufactured by Bosch Rexroth Indramat and assigned to the RD 500 Drive Controllers series. It serves as the power conversion stage in variable-speed AC motor systems, rectifying incoming three-phase line power and then inverting it to produce the voltage and frequency needed by the motor. In typical automation service, it manages the electrical conversion between the plant supply and the motor so rotating equipment can respond to changing load conditions. This makes it suitable for conveyors, mixers, and fan systems that need smoother acceleration and more consistent speed control than fixed-speed starters provide.

It is rated for a continuous motor load of 18.5 kW, which suits mid-range production machinery. The power section accepts 380 to 480 V input, and the supply type is a three-phase AC converter, so it can connect directly to common industrial power feeds. The permissible input fluctuation is ±10 %, allowing the controller to continue operating through normal line variation. Speed regulation uses U/f curve control, a scalar method that keeps voltage and frequency in step so induction motors maintain stable magnetic flux across the operating range. Because this method does not rely on motor feedback, it is well suited to general-purpose drive applications that require dependable speed adjustment without added feedback hardware.

For deceleration duty, a built-in brake chopper dissipates regenerated energy instead of allowing excess voltage to build on the DC bus. An integrated mains filter helps reduce conducted noise returning to the supply, while a heat dissipation panel supports panel mounting for units up to 18.5 kW without forced airflow. This arrangement supports compact cabinet layouts by combining braking and filtering functions within the drive. This model belongs to design generation 1. The option set is minimal, so the unit is supplied without additional option functions.