Product Description:

The BDU-100A is an Okuma base drive unit positioned within the BDU Servomotor Drives series. Designed as an AC drive interface, it converts and manages the direct-current link that feeds individual servomotor amplifiers. In a machining center or similar automation cell, the unit receives digital motion commands, supplies regulated power, and coordinates feedback so a BL servomotor can maintain commanded velocity and position. Its role is to bridge the numerical controller and the power stage, forming the electrical backbone for closed-loop axis control.

Drive logic receives motion words as a Digital RCON stream originating from the SVP board, eliminating analog drift. Internal electronics are powered by ±12 VDC and 5 VDC control rails that isolate low-level circuits from the energy bus. Separate control rails help command and supervision circuits remain stable while the main bus carries the larger power load. The common DC link supplies 300 VDC to downstream amplifiers, giving them a stable reservoir for acceleration demands. A hardware trip opens at 430 VDC if regenerated power raises the bus too high, and operation ceases below 220 VDC to avoid undervoltage misfires. These limits are supervised on the SVC board in the Base Unit + BDC + SVC assembly.

The internal DC power supply can feed up to 6 Drive Amplifiers, allowing a single base unit to support multiple axes. Each amplifier is matched to one 1 BL Motor, using the current ratings and commutation tables intended for that rotor type. Position recovery after power-up is immediate because the feedback path supports an Absolute Position Encoder rather than an incremental signal. For thermal and semiconductor protection, an early overcurrent warning appears at 10% of the IOCM trigger, prompting the controller to decelerate the load before the main cutoff engages. This helps reduce abrupt shutdowns when current rises toward the trip threshold.