Product Description:

The RAC 3.5-150-460-D0I-Z1-220 is an AC main spindle drive controller produced by Bosch Rexroth Indramat for the RAC Spindle Drive Controllers series. The unit converts three-phase supply power into regulated output for machine tool spindles, allowing CNC systems to command speed and direction precisely. By processing digital speed references and feeding the appropriate current to the motor, it maintains stable spindle dynamics that support machining accuracy, surface finish, and repeatable cycle times across automated production cells. It is intended for spindle duty rather than general axis positioning, so its control behavior is geared toward smooth speed regulation over the operating range. This makes it suitable for cutting, drilling, and contouring processes in which spindle response must remain consistent as load conditions change.

Its power section accepts a three-phase input of 3 × AC 400 V / 460 V, which covers typical European and North American mains, and can deliver up to 150 A of output to the spindle motor. Control electronics are energized separately through an AC 230 V control supply, which keeps logic functions on an independent supply path from the high-power section. Thermal energy generated by switching losses is removed through an internal blower fan, so cabinet airflow can remain moderate during sustained operation. The commanded speed arrives as a 16-bit digital command, allowing fine setpoint resolution and consistent response without the analog drift associated with voltage-based reference signals. This arrangement supports stable spindle speed control during rapid program changes and repeated production cycles.

For rapid deceleration cycles, the unit carries an additional bleeder resistor that dissipates regenerated energy instead of returning it to the mains. Position feedback can be forwarded to downstream devices because an incremental encoder output is wired in parallel with the primary feedback loop. Field wiring terminates on the X4 25-pole terminal, which keeps external connections organized at the drive interface. The unit is in series 3 and is identified as version 5. It does not include an additional encoder input, so the feedback arrangement is centered on a single motor encoder channel.