Digital guide
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Woodward 9902-400
Product Name: VSV / IGV Servovalve and Actuator System Component
Product Introduction: The 9902-400 is part of Woodward’s VSV (Variable Stator Vane) and IGV (Inlet Guide Vane) electro-hydraulic control product family, covered by Woodward manual 40136. As a member of the 9902 VSV/IGV series, it functions within the dual servovalve and actuator architecture providing closed-loop positioning of compressor variable geometry.
Detailed content
Technical Specifications: Configuration-specific parameters for 9902-400 are detailed in Woodward manual 40136. Maximum actuator output stroke: 3.445 inches (87.50 mm). Operating fluid: MIL-L-23699 or MIL-L-7808 turbine engine oil.
Functional Features:
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Dual torque-motor servovalve (independent IGV and VSV channels)
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Integral LVDT position feedback
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Optional accumulator interface
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System-level filtration
Application Scenarios: Industrial gas turbine VSV/IGV control; compressor anti-stall; part-load efficiency optimization.
Structural Characteristics: Aluminum servovalve case, through-hardened stainless steel internals. Marked ROD/HEAD/ACC ports. Mounts directly over the hydraulic pump with kit 8924-874.
Working Principle: Pilot stage meters pump pressure to the actuator based on torque motor command; LVDT feedback closes the position loop.
Installation Requirements: Mount over pump using kit 8924-874. Connect ROD/HEAD to actuator ports. ACC to external accumulator if required. Follow manual 40136 Chapter 2.
Usage Notes: Read manual 40136 before installation. Independent overspeed shutdown required. PPE mandatory. ESD handling precautions for electronics.
