Product Description:

The RAC3.5-200-460-L00-WI-220 is an AC main spindle drive controller built by Bosch Rexroth Indramat in the RAC Spindle Drive Controllers series. It is intended to govern high-power machine-tool spindles by translating incoming three-phase mains into controlled output that follows SERCOS speed commands. Within an automation cell, the device closes the torque loop between the CNC and the motor so that cutting, grinding, or drilling operations can hold programmed surface speeds under varying load.

The power section is designed for a supply of 380–460 V AC three-phase, and it delivers a continuous armature current of 92 A while maintaining a thermal continuous output of 35 kW. When short bursts are required for acceleration or heavy chip loads, the inverter can reach a peak mechanical output of 55 kW. A rated output current of 200 A sets the upper operating limit for the power semiconductors and bus capacitors, helping prevent overcurrent trips during rapid spindle ramps. Protective circuits supervise these limits even though no auxiliary bleeder, additional encoder input, or secondary interface is fitted, reducing component count and wiring complexity.

At an 8 kHz switching frequency, the controller sustains 30 kW, balancing electromagnetic noise against efficiency, and it can return braking energy to the mains with a continuous regenerative capability of 27 kW. Short-term regenerative peaks match the motoring peak, so dynamic deceleration does not overheat the DC link. Control electronics are powered from a dedicated 200 VA supply fed by a 230 V AC control line, isolating logic circuits from spindle transients. The housing carries an IP10 rating, so forced-air cooling from the cabinet is required, and the 49 kg mass must be supported on a rigid back panel. The open enclosure style places the controller inside a protected cabinet rather than directly on the machine frame.