1. Basic Identification

• Model: D633-7235

• Brand: MOOG

• Type: Direct‑Drive Electro‑Hydraulic Servo Valve (DDV)

• Series: D633 (ISO 4401 Size 03 / NG6, direct drive, no pilot)

• Rating: 40 L/min (Δp = 35 bar per edge)

2. Mechanical & Environmental

• Design: 4/3‑way, single‑stage, spool‑in‑bushing; permanent magnet linear force motor

• Mounting: ISO 4401‑03‑03‑0‑94 (NG6)

• Weight: ~2.5 kg

• Protection: IP67 (connector), IP65 (body)

• Temperature: Ambient −20 °C to +60 °C; Fluid −20 °C to +70 °C

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

3. Hydraulic Ratings

• Rated Flow: 40 L/min (Δp = 35 bar per land)

• Max Flow: 75 L/min

• Max Pressure (P/A/B): 350 bar (5,000 psi)Moog Inc.

• T Port: 50 bar (without Y); 350 bar (with Y)Moog Inc.

4. Electrical Data

• Supply: 24 VDC (18–32 VDC)Moog Inc.

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

• Feedback: 4–20 mA (spool position)

• Max Current: ≤1.2 A

• Connector: M12 (6+PE pins)Moog Inc.

5. Performance (Typical)

• Step Response (0–100%): ≤12 ms

• Hysteresis: ≤0.2%

• Linearity: ≤0.1%

• Resolution: ≤0.05%

• Null Leakage: ≤1.2 L/min

6. Key Features

• Direct drive, no pilot flow needed

• Pressure‑independent dynamics, fast response

• Spring‑centered on power loss (safe state)

• Excellent contamination resistance

• Integrated LVDT position feedback

7. Applications

• Medium‑to‑high flow precision hydraulic control

• Injection molding (medium–large machines)

• Metal forming, pressing & stamping

• Metallurgical test stands & rolling equipment

• Industrial robotics & motion bases

• Vibration & fatigue testing (40 L/min range)