Product Description:

The RAC 2.3-250-460-A00-Z1 is an AC main spindle drive controller in the RAC Spindle Drive Controllers series manufactured by Bosch Rexroth Indramat. It is intended for heavy-duty turning, milling, and grinding centers where the spindle must respond accurately to commanded torque and speed. The unit modulates three-phase line power for the attached spindle motor and supports closed-loop operation with current regulation, field-oriented control, and integrated protective functions. This arrangement helps maintain stable spindle performance during demanding machining cycles that require quick acceleration and consistent rotational accuracy.

The power section accepts 3 x AC 400 V, 50 Hz, +/-15%, or 3 x AC 460 V, so it can operate from common industrial line supplies without a separate transformer. The output bridge is rated for 250 A, which allows the controller to drive large spindle motors during prolonged cutting duty. Velocity reference is provided through a differential analog (+/- 10 V) input, allowing proportional speed commands while helping resist ground noise. Low-level control, ready, and fault signals are connected through X4 with 9 poles, which keeps external wiring compact. Thermal stress is reduced by a built-in blower that moves air across the heat sinks. Regenerative energy produced during rapid deceleration is handled by an additional bleeder, which protects the DC link from overvoltage.

The controller is supplied without an additional encoder input, so any secondary position channel must be connected outside the drive. The unit is series 2 and version 3. These identifiers correspond to the internal layout used for this build. During operation, the controller closes the spindle axis loop by enforcing current limits, monitoring bleeder temperature, and issuing fault messages to the supervisory CNC. This supports reliable spindle control in machine tools that depend on stable feedback processing and protective monitoring during continuous use.