Product Description:

The RAC 2.3-200-380-APD-Z1 is an AC main spindle drive controller produced by Bosch Rexroth Indramat for the RAC Spindle Drive Controllers series. It regulates spindle torque and speed so CNC tools can cut, grind, or drill at commanded rates with minimal lag. By converting command signals from a higher-level control into precise three-phase output, the unit serves as the central power stage in machining systems that require fast spindle acceleration and repeatable surface finishes. This type of controller is used where spindle speed must remain stable as cutting loads change during milling, turning, and grinding operations. The product is version 3 in design line 2.

The controller is configured for a three-phase mains connection of 3 x AC 400 V, 50–60 Hz, and its output stage is rated for 200 A, allowing it to drive large spindle motors during heavy material removal. Thermal management is handled by an internal blower, which moves air across the heat sink to keep the power electronics within their operating range. Velocity commands can be issued through an analog (±10 V) reference input, which supports direct speed control from the higher-level system. Position commands can also be sent as a 16-bit parallel digital position setpoint, allowing the controller to process position-related commands without additional signal conversion. These input options let the machine use either speed-loop or position-loop operation, depending on the spindle task.

Feedback is provided by a high-resolution INDRAMAT encoder, and the housing includes a 9-pole X4 terminal for the associated feedback connection. During rapid deceleration, the unit uses an additional bleeder to dissipate returned energy and help prevent DC-bus overvoltage. A separate encoder input for spindle feedback is also available, allowing an additional feedback channel for spindle orientation, homing, and monitoring during demanding machining cycles. This arrangement supports applications that require accurate spindle response during acceleration, speed holding, and controlled braking. The dedicated feedback path also helps keep signal handling separate from the power output section.