Product Description:

The RAC 3.5-100-460-AP0-W1-220 is an AC main spindle drive controller built by Bosch Rexroth Indramat for the RAC Spindle Drive Controllers series. The device coordinates torque and speed for the primary spindle motor in metal-cutting and high-speed machining centers, translating CNC commands into regulated three-phase power. By combining power conversion, protective monitoring, and command processing in one housing, it serves as the central control unit for spindle acceleration, holding torque, and controlled braking. This arrangement helps the machine maintain stable spindle behavior during speed changes and varying cutting loads.

The power stage accepts 3 x AC 400 V, 50 Hz, ±15% or 3 x AC 460 V, allowing direct connection to common industrial mains. The unit delivers 100 A of continuous armature current, while its control logic uses a separate AC 230 V / 50-60 Hz supply to support stable command processing. Heat is removed by an internal air blower, so no external ducting is required. Velocity references are supplied as an analog (± 10 V) command that is converted into pulse-width-modulated output for the spindle motor. Because the unit is supplied without an additional bleeder, an external resistor is required when the application returns substantial regenerative energy during deceleration.

An additional encoder input for spindle feedback can be enabled when dual-loop regulation is needed, supplementing the primary high-resolution Indramat encoder channel for improved low-speed control. Signal connections terminate on the X4, 9-pole interface, which keeps wiring organized inside the cabinet. This feedback arrangement supports accurate speed regulation during demanding spindle moves such as threading, rigid tapping, and low-speed cutting. Hardware coding marks the converter as series 3, version 5, while the RAC platform keeps the overall interface layout consistent across related units.