Product Description:

The RAC 2.3-250-460-D0D-W1 is an AC main spindle drive controller produced by Bosch Rexroth Indramat for the RAC Spindle Drive Controllers series. It controls the speed and torque of large machine tool spindles by supplying regulated three-phase power and interpreting digital setpoints from a numerical control. In an automated machine, the unit links the CNC command layer to the spindle motor so closed-loop speed control can be maintained during cutting, drilling, and grinding cycles. This makes it suitable for applications that need stable spindle response during changing loads.

The controller accepts a utility supply of 3 × AC 400 V / 460 V, so it can connect directly to standard factory mains without an intermediate transformer. Under rated conditions, it delivers 250 A of output for high-power induction or synchronous spindle motors used on heavy machining centers. Thermal management is provided by an internal blower, and the built-in fan pushes air through the heat sink channels to keep power components within a safe operating temperature range. Field wiring connects to the X4, 25-pole terminal block, which groups logic I/O and encoder signals in one location. Position commands are received through a digital position setpoint (16-bit parallel) interface, allowing high-resolution spindle orientation and tapping control from the CNC.

The speed command uses the same digital (16-bit parallel) bus, so speed and position signals share the same timing and scaling. For energy recirculation, the unit is supplied without an additional bleeder, so excess DC link energy must be handled by the connected motor or by an external braking module during deceleration. The controller also operates without an additional encoder input, which means only the primary spindle encoder is supported. The unit is Version 3, indicating the third version of this drive type.