R900704477 4WRZ25W8-325-7X/6EG24N9ETK4/D3M Servo valve German Rexroth proportional valve

FAQ:

1. Q: What is the main difference between this valve and the 4WRZE series?

   A:​ This valve (4WRZ) uses External Electronics (EE), meaning you must provide a separate amplifier card (e.g., VT-5000 series). The 4WRZE series has built-in onboard electronics (OBE).

2. Q: What does the /D3M suffix mean?

   A:​ The /D3​ suffix indicates an integrated pressure reducing valve (ZDR 6)​ for regulating pilot pressure. The /M​ suffix specifies standard NBR seals.

3. Q: How does the pilot oil configuration work?

   A:​ This valve (/6EG24N9ETK4) uses internal pilot oil supply (from main P port) and internal pilot oil return (to main T port). This "ET" configuration is the most convenient as it requires no external pilot lines, but you must ensure the main tank line (T-port) backpressure is controlled.

4. Q: Why choose this specific configuration?

   A:​ This model is ideal for high-flow applications (325 L/min) requiring simplified plumbing and cost-effective external amplifier control. The internal pilot drain (ET)​ reduces the number of hydraulic connections, while the integrated /D3 pressure reducer​ protects the pilot stage from system pressure fluctuations.

5. Q: What is the critical installation note?

   A:​ Since the pilot stage drains internally to T, you must ensure the main T-port backpressure is below 30 bar. High backpressure on T can prevent the pilot valve from draining properly, causing erratic main stage operation. Maintain high oil cleanliness (recommended NAS 1638 Class 8 or better for the main stage).