Product Description:

The VACII D11-B spindle drive controller is produced by Okuma and belongs to the VAC Spindle Drives series. Designed for industrial automation, the module governs three-phase inverter outputs so a machine-tool spindle follows programmed velocity and torque references. It combines a power section with digital logic that executes vector algorithms, allowing closed-loop regulation without external converters. By coordinating stator flux and rotor position, the unit helps lathes, mills, and grinders maintain cutting accuracy under changing load conditions. Integration with the host CNC occurs through dedicated multi-pin connectors on the front panel.

Connector CN1 carries drive commands and feedback through 50 contacts, while CN13 and CN3 each provide auxiliary I/O through 20 pins. Control processing is handled by the VAC Board II and VAC Card 1 set, while motor flux is calculated through Vector Control routines executed in real time. The cooling fan is powered by a 200 V line at 50/60 Hz, keeping the heat sinks within their operating temperature range. The power stage accepts a mains input ranging from AC 170-250 V at 50/60 Hz. This input range supports operation on compatible industrial power systems without requiring transformer tap changes.

The drive’s control section exchanges data with the CNC over an optical link, eliminating ground loops that can corrupt analog measurements. Logic power is produced by a transformer that delivers 19 VAC to the regulator, and a 16-bit CPU calculates current vectors and error terms during each cycle. Built-in monitors provide separate torque and spindle-speed signals for diagnostic use. The torque channel outputs ±10 V in proportion to phase current, while the second channel represents spindle speed across the same voltage span. Hardware protection uses fixed trip points for current-related faults. An IOCR trip occurs below -6.6 V, while IOCS and IOGR faults activate when sensed levels exceed 250 mV. These thresholds allow the controller to interrupt operation during abnormal loads before semiconductor stress increases.