Woodward 8915-1026

Digital guide

Product Description: This Woodward assembly combines a 3103-series stainless steel gas metering valve with an EM-35 electric actuator to form a complete fuel-control actuator/valve package. It is purpose-built for industrial gas turbine fuel control. The EM-35 actuator receives command signals from an electronic controller and drives the 3103 valve’s rotary metering sleeve with a fully electric drive system, achieving high-accuracy fuel flow metering. The unit is fully electric, low-maintenance, and factory-matched and base-calibrated for direct installation into turbine fuel systems.

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Detailed content

Technical Specifications:

Part Number: 8915-1026
Manufacturer: Woodward
Equipment Type: Actuator and valve combination unit
Valve Type: 3103 series stainless steel gas valve
Actuator Type: EM-35 electric actuator
Drive Mode: Fully electric servo drive (brushless DC motor + planetary gear reduction)
Position Feedback: Built-in high-precision resolver directly coupled to the valve metering sleeve
Control Compatibility: Compatible with Woodward analog and digital EM35 motor drivers
Actuator Output Shaft Rotation: 60° (limited by valve stroke)
Continuous Output Torque: ±25 N·m (±220 lb-in) maximum
Peak Output Torque: ±45 N·m (±400 lb-in) minimum
Clutch Release Torque: ±68 N·m (±600 lb-in)
Actuator Power: 28 Vdc nominal, 18–32 Vdc operating range
Current: 15 A continuous, 25 A peak (100 ms)
Steady-state Current: ~3 A
Valve Flow Range: 23–18144 kg/h (50–40000 lb/h)
Fuel Supply Pressure: Up to 6205 kPa (900 psia)
Differential Pressure Range: 172–6205 kPa (25–900 psi)
Gas Temperature Range: -40°C to +149°C (-40°F to +300°F)
Ambient Temperature Range: -40°C to +93°C (-40°F to +200°F)
Position Accuracy: ±0.50° (analog drive), ±0.10° (digital drive)
Bandwidth: >5 Hz
Stroke Time: 150 ms open, 80 ms close (28 Vdc, room temperature)
Explosion-proof Certification: CSA listed Class I, Division 1, Groups C & D; LCIE Zone 1 Group IIB

Key Features:

Actuator and valve are pre-matched with factory calibration, minimizing on-site commissioning effort.
EM-35 actuator uses brushless DC motor, fully electric drive with no hydraulic oil supply, reducing maintenance requirements.
Motor uses samarium-cobalt permanent magnets; rotor position detected via magnetic field orientation unit for precise control.
Planetary gear reduction provides high torque output with high transmission efficiency.
Clutch between motor and gearbox protects the motor and drive train when the valve is obstructed.
Output shaft directly drives the valve through a stainless steel torsion coupling, providing zero-backlash transmission.
Resolver is directly mounted on the valve metering sleeve; position feedback is precise and unaffected by intermediate transmission error.
3103 gas valve adopts rotary sleeve and shoe-type throttling structure, featuring self-cleaning and contamination resistance.
Valve design includes an inlet guide tube that directs fuel impurities toward the metering port, reducing debris accumulation in the valve body.
Metering sleeve support bearings are fully sealed from fuel to protect internal mechanisms.
On loss of power, valve spring loads to minimum fuel position, providing fail-safe protection.

Application Scenarios:

Fuel control for industrial gas turbine generator sets
Fuel management for gas compressor drivers
Gas supply regulation in combined heat and power (CHP) systems
Gas flow control in distributed energy stations
Fuel metering for dry low-emission (DLE) gas turbines
Marine and offshore platform gas power units

Material Composition:

Actuator Housing: Cast aluminum explosion-proof enclosure, surface treated
Motor Rotor: Samarium-cobalt permanent magnet, bonded and sleeve-fixed
Motor Stator: Fully encapsulated windings
Gearbox: Planetary gear reduction, high-strength alloy steel
Coupling: Stainless steel torsion coupling
Valve Body: Precision cast stainless steel
Metering Sleeve and Shoe: Fully hardened stainless steel, precision lapped
Seals: Fluororubber (FKM) or other fuel-resistant elastomer

Structural Characteristics:

Actuator and valve directly connected via adapter with no intermediate transmission link.
Rotary sleeve and shoe metering structure with excellent flow resistance characteristics.
Explosion-proof cast aluminum housing effectively dissipates motor heat to surrounding environment.
Output shaft supported by double roller bearings, providing strong load capacity.
Resolver directly coupled to valve metering sleeve, eliminating transmission chain error.
Compact overall structure, facilitating installation layout within turbine compartments.

Working Principle: The electronic controller sends a position command signal to the EM-35 driver. The driver energizes the brushless DC motor to produce precise rotation. The motor, after planetary gear reduction, directly drives the 3103 gas valve’s metering sleeve via a stainless steel torsion coupling to change the opening. The resolver detects the actual position of the metering sleeve in real time and feeds it back to the driver, forming a high-precision closed-loop position control. When the control system loses power or receives a shutdown command, the driver cuts off motor power and the valve’s built-in spring pushes the metering sleeve to the minimum fuel position, achieving fail-safe protection.

Installation Requirements:

Handle the unit carefully during handling and installation to avoid damage to seals, mounting surfaces, and factory adjustments.
Protect fuel connection ports with plastic plugs or caps when not connected to formal piping.
Ensure precise alignment of actuator and valve adapter via locating pins; ensure no jamming during installation.
Tighten actuator fixing bolts to specified torque.
Tighten coupling fixing screws to specified torque.
Configure a 25-micron absolute accuracy filter at the fuel inlet.
Route electrical connections through conduit interfaces; seal unused interfaces with explosion-proof plugs.
Use shielded cable for actuator and resolver wiring and ground properly.

Usage Notes:

Fuel cleanliness is critical to valve life; filters must be inspected and replaced regularly.
Fuel impurity levels must be strictly controlled: solids smaller than 10 microns not exceeding 30 ppm concentration, and larger than 10 microns not exceeding 0.3 ppm.
Regularly check the sealing of electrical connectors and the stability of position feedback signals.
Avoid operation under conditions of overpressure, overtemperature, or outside the voltage range.
Regularly check actuator housing temperature to ensure good heat dissipation.
Follow Woodward OEM recommendations for actuator maintenance intervals; return to factory for overhaul upon expiration to restore to “like-new” condition.
When replacing the actuator, no re-calibration of the valve is required because the resolver is directly installed on the valve metering sleeve.