Product Description:

The RAC 3.5-100-460-L00-Z1-220 is an AC main spindle drive controller manufactured by Bosch Rexroth Indramat for the RAC Spindle Drive Controllers series. The device sits between the machine tool's CNC and the spindle motor, translating digital velocity commands into controlled three-phase output while monitoring current and voltage in real time. Its purpose is to keep spindle speed stable under varying cutting loads so that surface finish and cycle time remain within required limits in industrial automation cells. It integrates power conversion, feedback processing, and protective functions into a single panel-mount module for continuous spindle operation.

Its power section accepts a three-phase supply of 3 × AC 400 V at 50 Hz ±15% or 3 × AC 460 V, allowing the same controller to operate on European or North American mains without rewiring. The unit can source up to 100 A of armature current, which supports large-frame spindle motors that require high starting torque and stable output under load. Control electronics are energized separately from an AC 230 V / 50–60 Hz utility feed, so diagnostics and stored settings remain available even when the main contactor is open. Velocity references arrive through the SERCOS interface, which provides fiber-optic communication with the CNC for rapid speed changes. All fiber-optic conductors terminate at the X4 optical waveguide terminal, helping reduce electrical noise near sensitive feedback circuits.

The built-in internal blower cooling circuit moves air directly over the heat sink and helps maintain semiconductor temperature during sustained high-current operation. Regenerative peaks created during deceleration are routed to an additional bleeder, which helps prevent DC-bus overvoltage during braking events. The controller is supplied without an additional encoder input when spindle position is already provided through the primary resolver channel, which simplifies external wiring. Within the RAC family, the unit is Series 3 and version 5.