R900765029 4WRZE10W6-85-7X/6EG24N9ETK31/A1D3M Rexroth Germany hydraulic proportional directional valve

Key Differences & Selection Guide

1. Q: What is the difference between "W6" and "E" spools?

   A:​ The W6-spool​ is an overlap spool​ designed for applications requiring smooth acceleration and deceleration (e.g., crane or winch control). It has a progressive flow characteristic. In contrast, the E-spool​ (zero overlap) is used for high linearity and precise speed control without a dead zone.

2. 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.

3. Q: What is the purpose of the /D3 suffix?

   A:​ The /D3​ suffix indicates that the valve is equipped with an integrated pressure reducing valve (ZDR 6). This valve regulates the pilot pressure supplied to the main stage, which can be used to limit the maximum force or speed of the actuator for safety or control purposes.

4. Q: Does this valve have LVDT feedback?

   A:​ No.​ Unlike the 4WREE valves you inquired about earlier, this standard 4WRZE model does not​ have LVDT feedback for the main spool position. It operates in open-loop for the main stage (though the pilot stage is closed-loop). For closed-loop control of the main stage, you would need a model with an "L" in the spool designation (e.g., E1..L).

5. Q: What is the critical installation note?

   A:​ Ensure the T-port backpressure is below 210 bar. The pilot stage relies on internal drain (T port), so excessive backpressure can cause malfunction. Maintain high oil cleanliness (recommended NAS 1638 Class 8 or better).