Product Description:

The VAC2-D8-A spindle drive is produced by Okuma as a member of the VAC Spindle Drives series. The unit is designed to regulate spindle speed and torque through the dedicated power electronics in its configuration, allowing the associated CNC control to command high-speed machining operations. By converting incoming three-phase power into controlled output for the motor, the drive integrates into Okuma machine tools where precise spindle performance is required. That controlled output supports stable acceleration, commanded speed changes, and repeatable torque delivery during cutting.

The drive protects its main DC circuit with a base circuit fuse rated at F7161, which is a 200 V, 5 A component that disconnects the supply if excess fault current flows. Thermal energy from the power stage is removed by a rear heat-sink fan, so cabinet airflow remains steady during prolonged cutting cycles. A single one diode module forms the free-wheeling path for regenerative currents, while six transistor modules switch the spindle phase voltages under vector control. Input protection is provided by a No-Fuse Breaker, allowing the unit to be isolated without replacing consumables after a short-circuit event. Command signals are delivered over an optical interface, which helps eliminate ground loops and improves noise immunity.

The logic and feedback circuits are driven by the VAC Card 1 controller board, while real-time gate drive and monitoring functions are handled by the VAC Board II control PCB. Overcurrent clearing is handled by a fuse bank of six, giving separate protection paths for auxiliary feeds and logic rails. The drive exchanges spindle commands with Okuma numerical controls such as OSP 5020 and the newer OSP 7000 variant, supporting parameter compatibility across machine generations. This layout separates supervisory control, switching control, and protective functions across dedicated sections within the drive.