Guangdong Yanhui Hydraulic Co., Ltd. is one of the leading manufacturers and suppliers of moog d661 series servo valve in China. We warmly welcome you to wholesale bulk moog d661 series servo valve for sale here from our factory. If you have any enquiry about pricelist and quotation, please feel free to email us.
Product Overview
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The Moog D661 Series is a highly reliable, two-stage electro-hydraulic servo valve with integrated electronics (OBE - On-Board Electronics), designed for precise closed-loop control of position, velocity, force, and pressure in demanding industrial hydraulic applications. Featuring an ISO 4401 Size 05 (NG10) mounting interface, the D661 series combines high flow capacity with outstanding dynamic response and exceptional stability.
Key Advantages
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Advanced ServoJet® Pilot Technology: Utilizes Moog's proprietary ServoJet® pilot stage for superior pressure recovery, high spool driving forces, and reduced contamination sensitivity compared to traditional flapper-nozzle designs.
Integrated On-Board Electronics (OBE): Features 24 VDC SMD electronics built directly into the valve, providing precise closed-loop spool position feedback and eliminating external amplifier card tuning.
High Flow Capacity & Dynamics: Delivers rated flows from 20 to 200 L/min (up to 250 L/min max flow) within a compact NG10 footprint.
Configurable Fail-Safe Modes: Offers multiple fail-safe options (e.g., mechanical spring return or hydraulic fail-safe) ensuring controlled system shutdown during power loss or fault conditions.
Robust Construction: Designed with IP65 enclosure protection and rugged cast/machined body construction capable of handling system pressures up to 350 bar (5,000 psi).
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Technical Specifications
▔▔| Parameter Category | Specification / Value | Additional Details |
| Mounting Interface | ISO 4401-05-05-0-94 (NG10 / D05) | Standard 5-port pattern with optional 2nd tank port |
| Valve Architecture | 2-stage pilot-operated with ServoJet® pilot | Closed-loop main spool position control via LVDT |
| Max Operating Pressure (Ports P, A, B) | 350 bar (5,000 psi) | High-pressure rated main body |
| Max Tank Port Pressure (Port T) | 210 bar (3,000 psi) internal Y / 350 bar external Y | Depends on pilot drain configuration |
| Rated Flow Rate | 20 to 200 L/min (5.3 to 52.8 gpm) | Available in multiple spool profile choices |
| Maximum Flow Rate | Up to 250 L/min (66 gpm) | At maximum valve opening and differential pressure |
| Step Response Time (0–100%) | 6.5 ms to 18 ms | Dependent on spool size and supply pressure |
| Supply Voltage | 24 VDC (18 to 32 VDC range) | Max power consumption approx. 300 mA |
| Electrical Connector | 6 + PE pole MS style connector (e.g., EN 175201-804) | Shielded mating connector required for EMC |
| Operating Fluid | Mineral-based hydraulic fluid (DIN 51524) | Synthetic fluids upon request |
| Cleanliness Standard | ISO 4406 $< 16/14/11$ (Recommended) | NAS 1638 Class 5 or 6 |
| Enclosure Rating | IP65 (EN 60529) with mated connector | Dust-tight and splash water resistant |
| Approximate Weight | 5.5 kg to 5.7 kg (12.3 lbs) | Compact, robust metal housing |
Applications
▔▔| Application Field | System / Equipment | Key Role of Moog D661 Servo Valve |
| Metallurgy & Steel Industry | Rolling mills, automatic gauge control (AGC), continuous casting | High-dynamic position and pressure control for strip thickness regulation. |
| Plastics & Rubber Processing | Injection molding machines, blow molding machines, extruders | Precise wall-thickness control (parison control) and dynamic injection speed profiling. |
| Power Generation | Steam and gas turbine control, governor EH hydraulic systems | Precise valve positioning for fuel valve actation and emergency trip fail-safe functions. |
| Heavy Machinery & Pressing | Hydraulic presses, die-casting machines, metal forming equipment | Synchronization of multi-cylinder presses and rapid high-tonnage pressure control. |
| Testing & Simulation | Hydraulic fatigue test rigs, flight simulators, structural testing | High-frequency closed-loop force, displacement, and acceleration control. |
Related Models
▔▔| Model Code / Part Number | Primary Features / Application Target |
| D661-4651 / D661-4651C | Standard closed-loop position & force control in steel mills |
| D661-4440E | High-flow press control and heavy industrial machinery |
| D661-4697C | Precise injection molding / blow molding axis control |
| D661-4086 | Multi-input retrofit control for die-casting machines |
| D661-4443C | Turbine speed regulation and power station EH systems |
| D661-4506C | Hydraulic test rigs and fatigue simulation systems |
| D661-5730 | Direct drop-in replacement model for older machinery upgrades |
FAQ
▔▔Q1: Can the Moog D661 replace older Moog 641 series proportional valves?
A: Yes. Moog provides direct cross-reference models (such as the D661-5000 series) designed specifically to replace legacy 641 series valves. However, attention must be paid to mounting bolt length (M6 x 60 mm vs. older M6 x 50 mm) and wiring adaptations due to differences in supply voltage and connector types.
Q2: How does the integrated electronic fail-safe mechanism work in the D661 series?
A: During power supply loss or if the voltage drops below 18 VDC, the integrated electronics de-energize the pilot system or release hydraulic pilot pressure, allowing the main spool to immediately shift to a predefined fail-safe position (center zero or end position) via mechanical spring force or hydraulic bias.
Contact Us
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Request a Quote Today to ensure your hydraulic system performs at its best with genuine components from Yanhui Hydraulic.
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