Product Description:

The RAC 2.2-250-380-A01-W1 is an AC main spindle drive controller produced by Bosch Rexroth Indramat as part of the RAC Spindle Drive Controllers series. It forms the power interface between a machine-tool CNC and the motorized spindle, regulating current, torque, and rotational speed so that cutting forces stay consistent during rapid load changes. By integrating into multi-axis automation cells, the controller lets the supervisory PLC synchronize spindle acceleration with feed motions, supporting precise chip removal and improved surface finish on metals, composites, or plastics.

This model connects to plant power through a three-phase supply rated at 3 x AC 400 V, 50-60 Hz. Inside the converter stage, a bus system sized for 250 A distributes filtered current to the output bridge that drives the spindle windings. Speed reference arrives through an analog (+/- 10 V) differential signal, allowing the motion controller to command bidirectional rotation with fine resolution. All low-voltage wiring terminates on the control board at X4, 9 poles, simplifying service access and loop checks. Thermal energy created by switching losses is removed by a built-in fan, which pulls cabinet air across the heat sink so continuous duty is possible without external ducts.

For position feedback, the unit provides an incremental encoder output that mirrors spindle shaft movement to downstream drives or the CNC. It is shipped without an additional bleeder, so surplus regenerative energy must be handled by the DC bus network or by mechanical damping. It also has no additional encoder input, which means any secondary measuring systems must interface through the machine control rather than the drive. The hardware platform corresponds to Version 2, standardizing diagnostic behavior across the second generation of this controller platform.