Product Description:

The RAC 3.5-150-460-AP0-W1-220 is an AC main spindle drive controller built by Bosch Rexroth Indramat and placed within the RAC Spindle Drive Controllers series. The unit supervises torque and speed on high-power machine-tool spindles, converting the speed demand from the CNC into regulated three-phase output for the motor. By integrating closed-loop encoder feedback and high-current switching stages, it supplies the dynamic control necessary to maintain surface finish, cutting accuracy, and cycle-time consistency in automated machining centers.

The controller connects directly to plant power through a three-phase supply of 3 × AC 400 V, 50 Hz ± 15 % or 3 × AC 460 V, so it can operate on both European and North American mains networks. With that input, it delivers a continuous output of 150 A, which is suitable for large-frame asynchronous spindle motors. Heat generated by the switching devices is removed by a built-in fan, allowing cabinet installation without external ducts. The velocity request arrives as a ± 10 V analog signal, and command and status lines terminate on the X4, 9-pole terminal strip. The drive ships without an additional bleeder, so excess regenerative energy must be handled by the DC bus or an external resistor bank.

For position verification, the electronics include an additional encoder input for spindle feedback, enabling synchronous monitoring of the motor-mounted sensor and the reference transducer on the machine. Control logic and gate drives are energized separately from the power stage by an AC 230 V 50–60 Hz service supply, which keeps diagnostics active even when the main line is isolated. The unit interprets signals from a high-resolution INDRAMAT encoder, supporting fine interpolation of spindle speed and synchronization signals. Hardware revision is identified as 5.