Technical Specifications:​ Specific standalone technical parameters for 8904-632 require reference to the official Woodward product manual. Based on the 8904 series combined unit architecture (exemplified by related models such as 8904-780), typical specifications include:

Structural Features:​ The actuator and valve are directly connected via an adapter with no intermediate transmission link. The rotary sleeve and gate metering structure provide excellent flow resistance characteristics. A dual-acting servo piston delivers powerful driving force. The hydraulic inlet fitting has a built-in 40 µm strainer for additional contamination protection. An electrical position feedback sensor is built into the actuator for closed-loop control.

Working Principle:​ The electronic controller sends an electrical command signal to the torque motor servo valve inside the TM-series actuator. The servo valve generates a pressure differential to drive the secondary spool, regulating the flow of hydraulic oil to the two ends of the dual-acting servo piston. The piston movement drives the final output shaft to rotate, thereby changing the opening of the valve metering sleeve. The built-in electrical position sensor detects the position in real time and feeds back to the controller, forming a high-precision closed-loop position control.

Installation Requirements:​ Handle with care during lifting and installation to avoid damaging seals, mounting surfaces, and factory calibration settings. Protect hydraulic and gas connection ports with plastic caps or covers when not connected to formal piping. The actuator is delivered pre-calibrated and purged of calibration fluid, ready for installation without additional cleaning or calibration. Confirm hydraulic supply pressure is within the specified range before installation. Bleed trapped air from the hydraulic system to prevent abnormal initial operation. Configure a filter meeting requirements at the gas inlet. Use shielded cable for electrical connections with proper grounding.

Usage Notes:​ Hydraulic oil cleanliness is critical to actuator life; maintain the specified filtration grade. Strictly control gas impurity content (solid particles < 10 µm: no more than 30 ppm; > 10 µm: no more than 0.3 ppm). Regularly inspect hydraulic system pressure and oil condition. Avoid operation under overpressure, overtemperature, or out-of-range viscosity conditions. Periodically check electrical connector sealing and position feedback signal stability. Follow Woodward OEM recommendations for maintenance intervals; return to factory for overhaul upon expiry to restore to “like-new” condition.