Product Description:

The RAC 2.2-250-460-A00-W1/S001 is manufactured by Bosch Rexroth Indramat within the RAC Spindle Drive Controllers series. It serves as a main spindle regulator in CNC machining centers, transfer lines, and grinding machines, converting reference signals from the numerical control into controlled three-phase power for the motor. In machine tools, this kind of regulator supports consistent spindle behavior during acceleration, load changes, and steady-state cutting. It maintains commanded speed and torque during continuous industrial operation and is used where stable spindle regulation is required over long duty cycles.

This controller connects to plant line power through 3 × AC 400 V with a tolerance of ±15% at 50 Hz, or it can operate from an alternate 3 × AC 460 V supply. It can deliver a continuous output of 250 A to the spindle motor, providing the current needed for sustained machining loads. Thermal management is handled by an integrated internal blower, so additional cabinet ducting is not required. Speed reference is processed through an analog ±10 V input channel for proportional control across the speed range, and field control wiring lands on the X4 9-pole terminal for enable, ready, and fault signals. That arrangement keeps the control connections grouped in one place and simplifies signal routing inside the panel.

The unit is supplied without an additional bleeder, so regenerative energy from rapid deceleration must be handled by external braking components when the application returns significant energy. It is also supplied without an additional encoder input, so motor feedback uses the primary spindle encoder routed to the CNC rather than a separate feedback channel inside the drive. Classified as an AC main spindle drive controller, it is suited to systems that use direct analog control and need a broad constant-power operating range. This layout is common in systems where the CNC manages feedback processing while the drive focuses on power conversion and spindle response. The controller is version 2 and uses the option-card arrangement assigned to that revision.