R900767522 4WRZE25W8-325-7X/6EG24N9K31/A1D3M Proportional servo valve Rexroth German hydraulic valve

FAQ:

1. Q: What is the main difference between this valve and the previous R900707649?

   A:​ This valve (R900767522) features an external pilot oil supply (X)​ and an integrated pressure reducing valve (/D3). R900707649 used internal pilot supply and had no pressure reducing valve. The /D3​ valve ensures stable pilot pressure independent of main system fluctuations, which is critical for high-performance applications.

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

   A:​ This valve (/6EG24N9K31) uses external pilot oil supply (X port) and external pilot oil return (Y port). You must provide clean, filtered pilot oil to the X port (typically 20–100 bar) and ensure the Y port drains directly to the tank with minimal backpressure (max 30 bar).

3. Q: Why choose the /A1 version?

   A:​ The /A1​ suffix (±10 V DC voltage input) is standard for many PLC analog output cards and motion controllers. It is simple to interface but can be susceptible to noise over long cable runs. For noisy environments, the /F1​ version (4–20 mA) is recommended.

4. Q: Why choose the W8 spool?

   A:​ The W8 spool​ provides a control area ratio of 2:1 (A:B)​ and is an overlap spool​ (O-type mid-position). It offers good metering characteristics and is suitable for applications requiring smooth control of asymmetric cylinders.

5. Q: What is the critical installation note?

   A:​ You must connect the external pilot drain (Y port) directly to the tank​ with a dedicated line. Backpressure on the Y port must be below 30 bar to ensure proper pilot valve function. Provide clean, regulated pilot pressure to the X port (20–100 bar). Maintain high oil cleanliness (recommended NAS 1638 Class 8 or better for the main stage).