Product Description:

The RAC 3.5-150-460-API-W1-220 belongs to the RAC Spindle Drive Controllers series from Bosch Rexroth Indramat. It is an AC main spindle drive controller that regulates spindle speed and torque in automated machining centers and similar production lines. By converting three-phase mains power into controlled motor output and processing feedback from high-resolution Indramat encoders, the unit supports closed-loop control for precision cutting and drilling operations. This helps the spindle maintain stable operation during speed changes and varying cutting loads.

This Series 3, Version 5 controller connects to plant power through a rated three-phase supply of 3 × AC 400 V at 50 Hz, or through an alternate line of 3 × AC 460 V. The control electronics are energized separately with AC 230 V at 50–60 Hz, which keeps the logic circuits isolated from the high-current path. The output stage can deliver a continuous spindle current of 150 A, supporting large-frame motors that require substantial startup and cutting torque. Speed reference comes from an analog command of ± 10 V, allowing the CNC or PLC to modulate spindle velocity through straightforward voltage scaling. The unit operates without an additional bleeder and relies on internal circuitry to dissipate regenerated energy during rapid deceleration.

Forced convection is supplied by an internal blower, which keeps the power semiconductors within thermal limits during high-duty cycles. Feedback wiring terminates on connector X4 with a layout of X4, 9 poles, which simplifies encoder hookup inside the cabinet. For downstream monitoring or master-slave spindle setups, the drive provides an incremental encoder output. It also offers an additional encoder input for spindle feedback, allowing dual-loop arrangements that combine motor-side and load-side position data for improved accuracy.