Spool hydraulic directional control valve 743

poppetpilot-operatedelectro-hydraulic

Description
The Moog valves of series 743 and 744 feature a simple, robust design for reliable, long-lasting operation. Key design elements include a field-replaceable first-stage filter and an internal null adjustment that serves as an electrical failsafe. The valves are FM-approved for non-hazardous locations and are primarily used in steam turbine applications.

Features

• 2-stage mechanical feedback valve for flow control
• Nozzle-flapper pilot stage for high resolution and low hysteresis
• High coil drive forces and rugged construction for extended service life
• Intrinsic-safe version available for applications requiring certification for potentially hazardous environments
• Optional 3-coil pilot configuration for additional protection against coil failure
• Field-replaceable pilot-stage filter
• Optional failsafe methods ensure predictable actuator movement on signal loss
• Designed to meet all requirements of General Electric specification 351A7620

Specifications
Specifications
Hydraulic data
Rated flow* | 743: 75 to 95 l/min | 744: 190 to 400 l/min
Standard configurations | 743: 95 l/min | 744: 190, 265 l/min
Max. operating pressure | 743: 210 bar | 744: 210 bar
Performance data
100% step response** | 743: 25 ms | 744: 110 to 170 ms
Frequency response*** | 743: 45 Hz | 744: 7 Hz
Electrical data
Rated signal**** | 743: 8 to 60 mA | 744: 17 to 96 mA
Standard configurations | 743: 16, 48 mA | 744: 17, 34.5, 96 mA
Physical data
Size (mounting pattern) | 743 & 744: Moog standard
Weight | 743: 1.54 kg | 744: 8.38 kg
Additional options | 743: Intrinsic-safe, magnetic null adjustment, vented motor cap, reverse polarity | 744: Additional options available

* @ ∆p 70 bar (1,000 psi)
** Response at 3,000 psi system pressure
*** at 90° phase lag
**** Single coil

Characteristics / Technical specifications

• Type: 2-stage mechanical feedback servo valve (series 743 and 744)
• Rated flow: 743: 75–95 l/min; 744: 190–400 l/min
• Standard flow configurations: 95 l/min (743); 190, 265 l/min (744)
• Max. operating pressure: 210 bar (both series)
• 100% step response: 743: 25 ms; 744: 110–170 ms
• Frequency response: 743: 45 Hz; 744: 7 Hz
• Rated signal: 743: 8–60 mA; 744: 17–96 mA
• Weight: 743: 1.54 kg; 744: 8.38 kg
• Options: intrinsic-safe version, magnetic null adjustment, vented motor cap, reverse polarity, optional 3-coil pilot configuration, failsafe methods