Product Description:

The RD51.1-4N-004-L-NN-NN-NN-FW is a variable-speed drive controller produced by Bosch Rexroth Indramat as part of the RD 500 Drive Controllers series. The unit converts fixed mains power into a modulated three-phase output so that induction motors can match process demands without mechanical gear changes. It fits cabinet-mounted automation where digital or relay logic issues a speed request and expects the controller to deliver stable torque under changing load conditions. This type of drive is commonly used where adjustable motor speed helps improve process control in general industrial machinery.

Its power section is designed for networks that deliver 380 to 480 V, and it tolerates line variation of ±10 %, allowing operation on lightly fluctuating utility feeds. The input uses a 3 x AC converter arrangement that rectifies and inverts the supply for motor use. Speed regulation follows U/f curve control, so voltage rises with frequency to help maintain motor flux across the operating range. Thermal management relies on forced air cooling, and a dedicated fan moves air across the heat sinks to remove waste heat from the power semiconductors. This operating method is suitable for standard asynchronous motors that do not require encoder-based feedback.

The drive is in Design Generation 1, so it follows the geometry and interface layout used for that generation. For applications that need only fundamental drive tasks, the controller is not equipped with additional options, which keeps the configuration straightforward. Dynamic braking energy must be handled externally because the controller is supplied without a built-in brake chopper. Line-side electromagnetic compatibility is supported by an integrated mains filter, reducing the need for separate filtering hardware in the cabinet.