Basic Identification

• Model: D633Z371B (also written D633-Z371B)

• Brand: MOOG

• Type: Single‑stage, pilotless direct‑drive electro‑hydraulic servo valve (DDV)

• Series: D633 (ISO 4401 Size 03 / NG6)

• Rated Flow: 16 L/min (Δp=35 bar per edge)

• Equivalent Model: D633‑R16KA1M0NSX2

Mechanical & Environmental

• Configuration: 4/3‑way, permanent magnet linear force motor, integrated closed‑loop electronics

• Mounting: ISO 4401‑03‑03‑0‑94 (NG6)

• Weight: ≈2.5 kg (5.5 lb)

• Protection: Connector IP67, body IP65

• Ambient Temp: −20 °C to +60 °C

• Fluid Temp: −20 °C to +80 °C

• Fluid: Mineral hydraulic oil, ISO 4406 18/15/12; viscosity 15–100 mm²/s

• Seal Material: FPM (fluoro rubber)

Hydraulic Specifications

• Rated Flow: 16 L/min (Δp=35 bar/edge)

• Max Working Pressure: P/A/B 350 bar; T (without Y) 50 bar

• Null Leakage: ≤0.5 L/min (typical)

• Features: Pressure‑independent dynamics, spring centering on power‑off

Electrical Specifications

• Supply: 24 VDC (18–32 VDC)Moog Inc.

• Control Signal: ±10 V, ±10 mA, 4–20 mAMoog Inc.

• Position Feedback: 4–20 mA

• Max Current: ≤1.2 A

• Connector: M12 (6+PE)Moog Inc.

Performance

• Step Response: ≤12 ms (0–100%)

• Hysteresis: ≤0.2%

• Linearity: ≤0.1%

• Resolution: ≤0.05%

Applications

• High‑flow precision control, 2‑axis synchronisation

• Material testing, fatigue rigs

• High‑precision positioning, hydraulic robots

• Injection moulding, die‑casting closed‑loop control