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Woodward 8915-969
Product Name: 3103 Gas Valve with EM35 Electric Actuator (Clutch-Equipped Variant)
Product Introduction: The 8915-969 is an all-electric fuel-metering assembly of the 3103 rotary sleeve valve with an EM35 actuator. It incorporates an internal slip-clutch and a higher peak-torque motor than the base EM35, protecting the gear train against impact loads while providing the precision required for DLE applications.
Detailed content
Technical Specifications:
- Valve Type: 3103 rotary sleeve gas valve
- Actuator Type: EM35 electric actuator with integral slip-clutch
- Gas Flow Range: 23 to 18,144 kg/h (50 to 40,000 lb/h)
- Inlet Pressure: up to 6205 kPa (900 psia); 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 service
- Minimum Differential Pressure: 172 kPa standard; 345 kPa (50 psid) for DLE
- Output Shaft Rotation: 60° (limited by valve mechanical stops)
- 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 bonded and encapsulated in the rotor
- 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 (28 Vdc, room temperature); 100 ms close at 137:1 reduction ratio
- Bandwidth: >5 Hz
- Position Accuracy: ±0.50° analog, ±0.10° digital (±6 arc-min RSS)
- Resolver Accuracy: ±0.05°
- Valve/Actuator Weight: ~44 kg (96 lb)
- Gas Connection: 2-inch 600# ANSI B16.5 flange
Features: Fully electric drive with no hydraulic oil source or associated maintenance; brushless DC motor with samarium-cobalt magnets, stator windings fully encapsulated; high-accuracy brushless resolver directly coupled to the metering sleeve; motor resolver for rotor position, valve resolver for output-shaft position; integral slip-clutch that slips at 1.5× maximum gear-train output force to protect the motor shaft and gearbox against full-speed impact on the hard stop; fault-detection circuitry monitoring the 4–20 mA interface, position controller, driver, and feedback; spring-return to minimum fuel on fault or external shutdown; analog 4–20 mA or digital serial communication with NetCon/MicroNet; flameproof actuator and resolver enclosure compliant with ATEX Category 2; CSA certification: Class I, Division 1, Groups C & D; Class I, Division 2, Groups B, C & D (NRTL/C); LCIE Zone 1 Group IIB; driver CSA-certified for Class I, Division 2, Groups A–D (NRTL/C).
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 with encapsulated stator; non-contact electromagnetic resolvers; stainless-steel torsional coupling; fuel-compatible elastomeric seals.
Structure: Planetary-gear EM35 actuator directly coupled to the 3103 valve body; dual resolvers (motor and valve); integral slip-clutch in the drive train; inlet guide tube with redundant sealing.
Working Principle: The controller demand drives the motor through the planetary reducer and slip-clutch to the valve sleeve. The resolvers provide closed-loop position feedback. The slip-clutch disengages at 1.5× the maximum output force to absorb impact against the mechanical stop. 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; wiring in accordance with Class I, Division 1 (North America) or Zone 1 (Europe) methods.
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; clutch is a protective device and is not intended for routine slipping.
