Product Description:

The RAC 3.5-150-460-L00-Z1-220 is an AC main spindle drive controller manufactured by Bosch Rexroth Indramat within the RAC Spindle Drive Controllers series. It receives three-phase line power and modulates it for high-speed machine-tool spindles, helping maintain the torque and speed accuracy needed in milling, turning, and grinding applications. In a machine tool, the controller regulates acceleration, steady running speed, and deceleration so the spindle follows command changes without unstable operation. Its role is to convert programmed motion commands into controlled rotational output while also protecting the motor and the connected supply during normal machine cycles.

Control electronics are supplied by AC 230 V at 50/60 Hz. The power stage accepts 3 × AC 400 V at 50 Hz with ±15% tolerance or 3 × AC 460 V. During full-load operation, the controller can deliver up to 150 A of output current, which supports spindle torque during continuous machining and other demanding duty cycles. Heat from the power semiconductors is removed by a built-in fan, which supports cabinet cooling without requiring a separate external heat exchanger in typical installations. Speed reference values are transmitted through a SERCOS interface, allowing deterministic communication with CNC or PLC systems so spindle speed changes stay synchronized with coordinated axis motion.

All fiber-optic command and diagnostic signals terminate at connector X4 for optical waveguides, which helps protect communication from electrical noise common in high-current spindle systems. Regenerative energy created during rapid deceleration is dissipated through additional bleeder resistors, preventing DC-bus overvoltage during braking events and reducing stress on the internal power section. This version is supplied without an additional encoder input, which simplifies wiring when only the primary spindle encoder is required. The drive is Series 3, and the unit is version 5.