Model Code Definition

D664 = NG25 ISO4401 mounting dimension, ServoJet jet-pipe pilot construction, built-in amplifier + full-stroke LVDT spool closed-loop feedback, high-flow D660 sub-series

4783 = Factory preset zero-overlap four-way spring-centered spool with tailor-made optimized flow gain, null position fully pre-calibrated at MOOG factory, standard amplifier circuit without special K-type parameter customization

Technical Specifications

Hydraulic Parameters

Rated Flow:522 L/min @35bar single-land differential pressure; peak instantaneous flow 1735 L/min @70bar supply differential pressure

Max Working Pressure:P/A/B main ports up to 350bar; internal T drain ≤210bar; external Y drain supports full 350bar rated working pressureMoog Inc.

Full Stroke Step Response:≤28.8ms under nominal 210bar supply oil pressureMoog Inc.

Control Precision:Hysteresis＜0.21%FS, Resolution＜0.061%FS, overall thermal drift(-20~+80℃)＜1.92%FS after factory gain fine calibration

Null Leakage:0.23~1.72 L/min subject to original spool machining tolerance

Working Medium:Anti-wear mineral hydraulic oil, cleanliness NAS6~7 / ISO4406 17/14/11, operating fluid temperature -20℃~+80℃

Net Weight:5.82kg

Electrical Parameters

Input Power Supply:24VDC wide input range(18~32VDC), static standby current ≤855mAMoog Inc.

Default Control Command:Factory standard ±10VDC differential analog input; ±10mA /4~20mA current signal optional via factory customized modification

Connector:11-pin circular aviation receptacle, IP65 protection after complete cable assemblyMoog Inc.

EMC Compliance:Conforms to EN55011 industrial electromagnetic compatibility standard

Port & Connection Configuration

Hydraulic Interface:ISO4401 NG25 standard hole layout including P supply port, A/B actuator control ports, separated built-in T internal drain and dedicated Y external drain; pre-mounted original NBR mounting gasket, unused X pilot port sealed with factory blank plug for non-external pilot oil application

Electrical Interface:11-pin circular socket integrates 24V power supply, ±10V command signal and full-travel LVDT feedback wiring; double-shielded control cable required with single-point cabinet grounding, no fieldbus communication functionMoog Inc.

Core Functions

1.Patented ServoJet jet-pipe pilot delivers outstanding dirt resistance compared with conventional nozzle-flapper pilot, guaranteeing long-term stable operation under medium-impurity hydraulic oil in metallurgical production sites and test laboratories.

2.Optimized fixed flow gain of 4783 spool satisfies high-precision large-flow closed-loop control requirement; four-way zero-lap spool realizes precise position/speed/force closed-loop adjustment for hot/cold rolling mill and heavy forging master cylinder; onboard LVDT automatically compensates temperature-induced spool drift.

3.Spring-centered fail-safe neutral structure: main spool automatically returns to middle position once power cuts off to block A/B oil passage and lock hydraulic actuator to prevent unexpected equipment runaway damage.

4.Factory pre-calibrated built-in amplifier features strong anti-interference capacity to adapt long-distance analog wiring under severe industrial environment.

Typical Application

Hot & cold continuous rolling mill AGC roll gap closed-loop servo regulation, heavy slab hydraulic forging press cylinder accurate flow control, full-scale hydraulic component fatigue test bench, large aluminum/steel extrusion forming equipment, marine hydraulic servo test system.

Installation & Maintenance Instructions

1.Install 3μm high-precision inline high-pressure filter on upstream P supply pipeline; replace filter cartridge after the first 15 working days of equipment commissioning startup.

2.Arrange power cable and shielded control wire inside separated wiring ducts to avoid inverter harmonic interference to analog control signal; fix valve with factory specified bolt tightening torque and standard flat washers.

3.Flow gain and null offset parameters of standard 4783 version are fully preset at MOOG factory; only minor on-site potentiometer fine-tuning is permitted; complete disassembly of ServoJet pilot assembly and main spool unit is strictly forbidden.

4.Seal idle spare T/Y drain ports with original factory blank plugs during spare part storage; store valve in dry dustproof warehouse to avoid NBR rubber seal ageing and subsequent oil leakage.