Product Description:

The RAC 2.3-250-380-API-Z1 is produced by Bosch Rexroth Indramat for the RAC Spindle Drive Controllers series. Designed for cabinet installation alongside Indramat inverter modules, the unit governs main spindle motors in CNC machines and other production equipment, converting drive commands from a higher-level control into precise speed and torque regulation for the attached AC spindle. By managing acceleration, braking, and steady-state rotation, it links the numerical control to the mechanical spindle and supports high-speed metal-cutting, grinding, and drilling processes in automated lines.

For power integration, the controller accepts a three-phase supply of 3 x AC 400 V, 50–60 Hz, matching standard plant mains without a transformer. Its output channel is rated at 250 A, allowing rapid starts of large spindle rotors without current derating. Thermal stability is maintained by a built-in fan that circulates cooling air through the housing during continuous duty. Speed references arrive through a ±10 V analog input, so conventional PLC or CNC hardware can modulate velocity with minimal conversion circuitry. Field wiring for auxiliary functions is consolidated on the X4 9-pole connector, simplifying encoder, sensor, and brake terminations.

Energy released during deceleration is diverted to an additional bleeder, preventing DC-bus overvoltage when heavy spindles brake abruptly. Precision feedback enters through an additional encoder input for spindle feedback, while a synchronized incremental encoder output lets downstream axes share real-time spindle position. Internally, motion is resolved with a high-resolution Indramat encoder, improving interpolation at low speeds and supporting better surface finish. The controller is Series 2 and Version 3, which supports compatibility with Indramat diagnostics and parameter sets used in multi-drive installations.