Product Description:

The RAC 3.1-150-460-A0I-W1-220 is an AC main spindle drive controller manufactured by Bosch Rexroth Indramat for the RAC Spindle Drive Controllers series. Installed between the CNC control and a high-speed spindle motor, it regulates torque and speed during turning, milling, or grinding processes. The device belongs to series 3 and version 1 of the platform, linking directly to induction or synchronous spindle machines that require finely controlled current and reliable field-oriented regulation. Designed for cabinet mounting, the unit combines power conversion, speed reference handling, and internal cooling in a single housing.

Its control electronics draw auxiliary power from AC 230 V at 50/60 Hz, ensuring compatibility with standard shop supplies. The power bridge is designed for 3 x AC 400 V, 50 Hz, ±15%, or 3 x AC 460 V mains, so the same model can serve both 400 V European networks and 460 V North American plants. Continuous motor current capability reaches 150 A, giving adequate headroom for heavy cutting cycles without derating. Thermal stability is maintained by an internal blower that circulates air through the integrated heat sink, eliminating the need for ducted cabinet air. Spindle speed is commanded through an analog (±10 V) reference, allowing a simple interface to analog CNC spindle channels and quick velocity changes during tool transitions.

The signal cluster is accessed on the X4, 9-pole terminal, simplifying wiring by grouping enable, reference, and feedback lines on one connector. Because the unit ships without an additional bleeder, excess regenerative energy must be handled by the internal circuitry or a separately mounted resistor if braking cycles are intense. It is delivered without an additional encoder input, so external position sensors cannot be connected. However, the controller provides an incremental encoder output that mirrors spindle position for downstream CNC or monitoring equipment.