Product Description:

The PSU-20-ACL is a servo power supply from Okuma's PSU Servo Power Supplies series. Installed inside the automation cabinet, it rectifies incoming AC power and maintains a stable DC link for the connected servo amplifiers that drive motion axes and spindles. That internal bus gives the amplifier section a consistent energy source during acceleration, deceleration, and changing spindle demand, which helps motion remain stable across the machine. Because the power conversion is handled in one supply stage, cabinet power distribution can remain more orderly than with separate rectification at each axis module.

The supply accepts 3-Phase AC mains with an input range from 180 Vrms to 253 Vrms. It operates on 50/60 Hz line frequency and tolerates up to 10% Max variation from the selected nominal value without shutting down. This input window supports operation on industrial power systems that remain within normal tolerance bands. A maximum supply inductance of 140 µH limits the rise of fault current, while the grounding scheme follows Class D to help control leakage paths. The incoming network should also remain properly balanced so the rectifier stages are not exposed to uneven loading, and symmetrical phase conditions help the input bridge conduct evenly across all three legs.

The converter generates a regulated internal bus of 300 VDC for the drive modules. Frequency drift is limited to ±1 Hz, mains imbalance can reach 5% Max before the protective threshold is exceeded, and the protective earth must remain below 100 Ω Max for reliable fault clearing. Internal monitoring watches these supply conditions and issues a fault before abnormal input behavior can disturb connected servo drives. A regulated DC bus also helps connected modules share a common power source during coordinated motion, especially when several axes are active at the same time.