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Woodward 8915-971
Product Name: 3103 Gas Valve with EM35 Electric Actuator (Dual-Resolver Variant)
Product Introduction: The 8915-971 is a 3103 rotary sleeve gas valve driven by an EM35 electric actuator, configured with dual resolvers for redundant position detection. It is designed for high-precision fuel metering in industrial gas turbines, including DLE applications where no hydraulic oil source is available and where operation in hazardous areas is required.
Detailed content
Technical Specifications:
- Valve Type: 3103 rotary sleeve gas valve
- Actuator Type: EM35 electric actuator with dual resolvers
- Gas Flow Range: 23 to 18,144 kg/h (50 to 40,000 lb/h)
- Inlet Pressure: Enhanced up to 6205 kPa gauge (900 psig); CE limited to 4964 kPa (720 psia)
- Differential Pressure: 172 to 6205 kPa (25 to 900 psi)
- Fuel Temperature: -40 to +149 °C
- Ambient Temperature: -40 to +93 °C
- Metered Fuel: Natural gas, propane, methane (specific gravity 0.5 to 1.05)
- Filtration: 25 μm absolute (β=75)
- Flow Accuracy: ±5% of point or ±0.25% of maximum flow; ±2% of point for DLE
- Minimum Differential Pressure: 172 kPa standard; 345 kPa for DLE
- Output Shaft Rotation: 60°
- Continuous Output Torque: ±24.9 N·m (±220 lb-in)
- Peak Output Torque: ±62.4 N·m (±552 lb-in)
- Clutch Slip Torque: ±68 N·m (±600 lb-in)
- Torque Constant: 1.8 N·m/A
- Motor: Brushless DC with samarium-cobalt permanent magnets
- Power Input: 28 Vdc nominal (18–32 Vdc operating range)
- Current: 37 A max for 50 ms, 15 A max continuous
- Slew Rate: 150 ms open / 80 ms close on 50° stroke
- Bandwidth: >5 Hz
- Position Accuracy: ±0.50° analog, ±0.10° digital
- Resolver Accuracy: ±0.05°
- Component Weight: ~44 kg (96 lb)
- Gas Connection: 2-inch 600# ANSI B16.5 flange
Features: Fully electric drive with no hydraulic oil source; brushless DC motor with samarium-cobalt magnets and fully encapsulated stator windings; high-accuracy brushless resolver directly coupled to the metering sleeve; dual-resolver redundant position detection; internal slip-clutch protecting the drive train; fault detection and automatic protection; spring-return to minimum fuel on power loss; analog 4–20 mA or digital serial control; flameproof design with CSA and ATEX certification; self-cleaning geometry for sour-gas service.
Applications: Industrial gas-turbine fuel control; installations with no hydraulic oil source; hazardous-area fuel control; DLE high-precision control; interfaced with Woodward NetCon and MicroNet systems; power generation, cogeneration, and chemical-process applications.
Materials: Stainless-steel valve body; through-hardened stainless-steel internal parts; flameproof cast-aluminum actuator housing; samarium-cobalt brushless DC motor; non-contact electromagnetic resolver; stainless-steel torsional coupling; fuel-compatible elastomeric seals.
Structure: Planetary-gear EM35 actuator directly coupled to the 3103 valve body; dual resolvers sensing the metering-sleeve position; inlet guide tube with redundant sealing; integral slip-clutch.
Working Principle: The controller demand drives the motor to vary the valve sleeve position. The dual resolvers provide redundant closed-loop position feedback. On power loss or fault the spring returns the valve to minimum fuel.
Installation Requirements: Flameproof cover bolts torqued to specification; explosion-proof cable glands and conduit sealing; lifting aids for the ~44 kg assembly; proper earthing; 25 μm absolute fuel filtration upstream of the valve.
Usage Precautions: Motor cable must not be coiled; power must be isolated for maintenance in hazardous areas; periodic cable inspection; surface-temperature limits must be respected; mechanical stop screws must never be adjusted; valve freedom of movement must be verified after prolonged shutdown.
