Digital guide
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Woodward 9902-402
Product Name: VSV / IGV Servovalve and Actuator System Component
Product Introduction: The 9902-402 is a member of Woodward’s VSV (Variable Stator Vane) and IGV (Inlet Guide Vane) electro-hydraulic control product family, covered by Woodward manual 40136. Within the 9902 VSV/IGV series, it functions as part of the dual servovalve and actuator system providing closed-loop hydraulic positioning of compressor variable geometry.
Detailed content
Functional Features:
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Dual torque-motor servovalve architecture (IGV + VSV)
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Integral LVDT feedback per actuator
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Optional accumulator interface via “ACC” port
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System filtration protecting essential orifices
Application Scenarios: Industrial gas turbine compressor VSV/IGV control; anti-stall protection; part-load efficiency optimization.
Structural Characteristics: Aluminum servovalve case with through-hardened stainless steel internal parts. Marked hydraulic ports (ROD, HEAD, ACC). Servovalve installs directly over the hydraulic pump via kit 8924-874.
Working Principle: Hydraulic pump pressure is metered by the torque-motor-driven pilot stage to the actuator. LVDT feedback closes the position loop in the electronic final driver.
Installation Requirements: Install servovalve over pump using kit 8924-874. Connect ROD/HEAD ports to the matching actuator ports. Connect ACC to external accumulator if required. Ensure filtration. Follow manual 40136 Chapter 2 for receiving, storage, and installation.
Usage Notes: Read the entire manual 40136 before installation, operation, or servicing. Turbine requires an independent overspeed shutdown device. Use proper PPE. Emergency shutdown readiness during start-up is mandatory. Observe ESD handling precautions.
