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Woodward 8915-460
Product Name
AC LVDT (Alternating Current Linear Variable Differential Transformer) position sensor, HLR-750-7500 series.
Product Overview
The Woodward 8915-460 is a non-contact displacement detection component that provides high-precision linear displacement measurement for valves, actuators, and other moving parts. It is widely used in gas turbine fuel control, servo valve feedback, and industrial automation.
Detailed content
Technical Specifications
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Sensor type: AC LVDT
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Corresponding model: HLR-750-7500 series
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Housing diameter: 0.750 in (19 mm)
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Stroke range: 7.5 in (based on series code 7500)
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Linearity error: ≤ ±0.15% FSO (typical), ≤ ±0.25% FSO (maximum)
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Zero voltage: 0.5% full scale
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Repeatability: 0.01% full scale
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Hysteresis: 0.01% full scale
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Operating temperature: -54 °C to +135 °C (standard), -54 °C to +204 °C (high-temperature type)
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Thermal coefficient: < -0.02%/°C full scale
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Humidity: 90% relative humidity
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Expected life: Over 100 million operating cycles
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Shock rating: 1000 g, 11 ms
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Vibration rating: 20 g to 2 kHz
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Protection class: IP61 to IP68
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Lead wire: 28 AWG Teflon-insulated wire, standard length 305 mm
Functional Features
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Non-contact measurement principle with no friction or wear, theoretically unlimited service life
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Free armature design for easy coupling with external mechanical components
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Epoxy-potted coil windings with excellent shock and vibration resistance
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Typical linearity better than ±0.15%
Application Scenarios
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Gas turbine valve position feedback
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Hydraulic and pneumatic actuator stroke monitoring
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Fuel control system linear displacement detection
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High-precision positioning in industrial process automation
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Flow control feedback loops in the energy sector
Material Composition
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Housing: Fully stainless steel construction, corrosion-resistant and oxidation-resistant
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Coil bobbin and windings: High-temperature insulating material with epoxy potting protection
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Armature: High-permeability alloy with treated surface to reduce wear
Structural Characteristics
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Compact 19 mm diameter design suitable for space-constrained environments
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Free armature structure allowing connection to target mechanical components via extension rods
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Sealed design preventing ingress of moisture, dust, and chemical contaminants
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Standardized electrical interface compatible with mainstream LVDT signal conditioners
Working Principle
The sensor operates based on the electromagnetic induction principle. An AC excitation voltage is applied to the primary coil, inducing voltages in two symmetrically arranged secondary coils. As the armature moves within the coil assembly, the induced voltages in the two secondary coils change differentially. By measuring the ratio of the difference to the sum of the two secondary coil output voltages, a precise electrical signal proportional to the armature displacement is obtained. Since there is no physical contact between the armature and the coil, the sensor experiences no mechanical wear.
