Description
D138-002-001: Product Overview
The MOOG D138-002-001 is a two-stage electrohydraulic servo valve from the D138 Series, engineered for precision control of hydraulic actuators in dynamic systems requiring moderate-to-high flow rates and compact integration. In an automation architecture, it serves as the critical interface between electronic controllers (e.g., PLCs, motion controllers) and hydraulic actuators (e.g., cylinders, small motors), converting low-power electrical command signals into proportional hydraulic flow and pressure. The D138 Series balances robust construction with millisecond-level response, making it suitable for laboratory test rigs, small-scale industrial machinery, and simulation systems where space constraints coexist with accuracy demands. This valve operates on a nozzle-flapper pilot stage (for signal amplification) and a sliding spool main stage (for flow modulation), ensuring stable output across varying loads. The “002-001” configuration denotes a single-channel design (optimized for straightforward integration into single-actuator systems), distinguishing it from dual-channel variants like D138-002-012. It is typically deployed in closed-loop setups with position/force feedback, where adjustments to the input signal maintain desired actuator behavior—essential for avoiding overshoot in high-accuracy positioning tasks.
MOOG D138-002-001
D138-002-001: Technical Specifications
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Model Number: D138-002-001
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Manufacturer: Moog Inc.
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Product Type: Electrohydraulic Servo Valve (Two-Stage)
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Valve Configuration: 4-way spool (symmetrical flow paths, spring-centered), single-channel (002-001 configuration)
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Nominal Flow: 15 GPM (56.8 L/min) @ 1000 psi (69 bar) differential pressure
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Maximum Pressure: 3000 psi (207 bar) per port
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Input Signal: ±10VDC (standard), ±40mA (via optional G123 series amplifier)
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Response Time: <20 ms (step input to 90% flow)
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Resolution: <0.15% of full scale (hysteresis <0.6%)
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Operating Temperature: -20°C to +80°C (-4°F to 176°F) (fluid-dependent)
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Fluid Compatibility: Petroleum-based oils (ISO VG 32/46), phosphate ester synthetic fluids (e.g., Skydrol)
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Weight: 2.2 kg (4.9 lbs, valve body only)
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Dimensions: 152mm (L) x 83mm (W) x 108mm (H) (approximate)
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Certifications: CE, ISO 9001 (manufacturing standard), AS9100 (aerospace quality)
Core Features & Customer Value
Single-Channel Simplified Integration: The 002-001 configuration provides a single 4-way spool circuit, eliminating the complexity of dual-channel synchronization. For engineers integrating into single-actuator systems (e.g., a uniaxial test rig), this reduces wiring and programming effort by 30% compared to dual-channel valves.
Moderate-Flow Precision Control: With 15 GPM nominal flow and <0.15% resolution, the valve delivers linear output proportional to the ±10VDC input. In material testing machines, this ensures force application accuracy within ±0.5% of setpoints—critical for valid tensile/compression data.
Balanced Dynamic Response: A <20 ms response time allows rapid adjustment during transient conditions (e.g., cyclic loading in fatigue tests). In small hydraulic presses, this minimizes actuator lag, improving cycle time consistency by 10-15% compared to slower alternatives.
Rugged Construction for Industrial/Aerospace Use: The valve body is forged aluminum with a hardened spool, resisting corrosion and wear from synthetic fluids (common in aerospace) or contaminated oils (industrial environments). For maintenance teams, this extends service life to 12,000+ operating hours, reducing replacement costs.
Seamless System Integration: Native compatibility with Moog G123 amplifiers (for ±40mA signals) and standard analog controllers (PLCs, PID loops) enables plug-and-play setup. The single-channel design integrates with PLCs via analog outputs, simplifying centralized control of single-actuator systems.
MOOG D138-002-001
Typical Applications
The D138-002-001 is deployed in systems prioritizing single-actuator control, moderate flow, and precision:
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Material Testing: Universal testing machines (tension/compression control), fatigue test rigs (cyclic load application up to 10 Hz).
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Laboratory Equipment: Benchtop hydraulic trainers, fluid power demonstration systems.
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Small Industrial Machinery: Robotic part feeders (positioning accuracy ±0.1mm), small press brakes (bend angle control).
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Simulation Systems: Flight control surface simulators (small-scale actuators), vehicle suspension test rigs.
In a university materials lab, for example, the D138-002-001 controls a hydraulic cylinder in a fatigue test rig for composite materials. Its <20 ms response ensures the cylinder follows a 5Hz sinusoidal load profile within ±0.1mm displacement accuracy—critical for collecting valid material property data.
