Woodward 8915-1152

Digital guide

Product Name: 3103 Series Stainless Steel Gas Valve with EM35MR All-Electric Actuator Package

Product Overview: 8915-1152 is a fully matched, factory-calibrated actuator-and-valve combination unit manufactured by Woodward. It integrates a 3103-series stainless steel gas valve with an EM35MR all-electric actuator, driven by a brushless DC motor with planetary gear reduction. The package is designed to eliminate hydraulic oil supply entirely, removing hydraulic contamination and maintenance overhead from gas turbine fuel control.

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Detailed content

Technical Specifications:

Actuator Drive: All-electric servo drive (brushless DC motor + planetary gear reducer)
Position Feedback: Built-in high-precision resolver directly coupled to the valve metering sleeve
Control Compatibility: Works with Woodward DVP digital valve position controller and EM 24V digital driver
Actuator Power Supply: 28 Vdc nominal (18–32 Vdc operating range)
Actuator Current: 15 A continuous, 37 A peak (50 ms), ~3 A steady-state
Output Shaft Rotation: 60° (limited by valve travel stops)
Continuous Output Torque: ±25 N·m (±220 lb-in) maximum
Peak Output Torque: ±62 N·m (±552 lb-in) minimum
Clutch Release Torque: ±68 N·m (±600 lb-in)
Valve Flow Range: 23 to 18,144 kg/h (50 to 40,000 lb/h)
Gas Supply Pressure: Up to 4,964 kPa absolute (720 psia) standard; enhanced up to 6,205 kPa gauge (900 psig)
Differential Pressure Range: 172 to 6,205 kPa (25 to 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

Functional Features:

Actuator and valve are pre-matched and factory-calibrated, minimizing on-site commissioning effort
Brushless DC motor with samarium-cobalt permanent magnets; rotor position detected by magnetic field orientation unit for precise control
Planetary gear reduction delivers high torque output with high transmission efficiency
Slip clutch between motor and gearbox protects motor and drive mechanism when valve is obstructed
Output shaft drives valve directly via stainless steel torsional coupling for zero-backlash transmission
Resolver installed directly on the valve metering sleeve for position feedback immune to intermediate transmission error
3103 gas valve uses rotary sleeve and gate-type throttling structure with self-cleaning and anti-contamination capability
Inlet guide tube directs gas contaminants toward the metering port, reducing impurity accumulation in the valve body
Metering sleeve support bearings are positively sealed from gas to protect internal mechanism
Spring-loaded to minimum fuel position on power loss — built-in fail-safe protection

Application Scenarios: Industrial gas turbine generator set fuel control; gas compressor drive fuel management; combined heat and power (CHP) gas supply regulation; distributed energy station gas flow control; dry low-emission (DLE) gas turbine fuel metering; marine and offshore platform gas power units.

Material Composition: Stainless steel valve body; hardened stainless steel internal parts; cast aluminum explosion-proof actuator housing; samarium-cobalt permanent magnet brushless DC motor; stainless steel torsional coupling; non-contact electromagnetic resolver.

Structural Characteristics: EM35MR actuator connected via adapter directly to 3103 valve body; resolver coupled to metering sleeve through stainless steel bellows; inlet guide tube with redundant sealing design; integral explosion-proof conduit entries.

Working Principle: The electronic controller sends a position command to the EM driver, which energizes the brushless DC motor for precise rotation. The motor, after planetary gear reduction, drives the 3103 gas valve metering sleeve through a stainless steel torsional coupling to change the opening. The resolver detects the actual position of the metering sleeve in real time and feeds back to the driver, forming a high-precision closed-loop position control. On power loss or shutdown command, the driver cuts motor power and the internal spring pushes the sleeve to minimum fuel position for fail-safe protection.

Installation Requirements:

Handle with care during lifting and installation to avoid damaging seals, mounting faces, and factory calibration settings
Protect gas connection ports with plastic plugs or caps when not immediately connected to piping
Align actuator-to-valve adapter with locating pins to ensure no binding
Tighten actuator mounting bolts and coupling set screws to specified torque
Install a 25 µm absolute-accuracy gas filter upstream of the valve inlet
Route electrical connections through conduit entries; seal unused entries with explosion-proof plugs
Use shielded cable for actuator and resolver wiring with proper grounding

Usage Precautions:

Gas cleanliness is critical to valve life — inspect and replace the filter regularly
Strictly control gas contaminant levels: solid particles <10 µm diameter not exceeding 30 ppm by volume; >10 µm diameter not exceeding 0.3 ppm by volume
Do not operate beyond rated pressure, temperature, or voltage range
Regularly check actuator housing temperature to ensure adequate heat dissipation
Follow Woodward OEM-recommended maintenance intervals; return to factory for overhaul at end of service life
Actuator replacement requires no valve re-calibration because the resolver is mounted directly on the valve metering sleeve