R900707649 4WRZE25W8-325-7X/6EG24N9K31/A1M Proportional hydraulic servo valve from Rexroth, Germany

FAQ:

1. Q: What is the main feature of this valve?

   A:​ This model (4WRZE) features Integrated On-Board Electronics (OBE), meaning the amplifier is built into the valve. It accepts a ±10 V control signal (/A1)​ directly, eliminating the need for an external amplifier card.

2. Q: How does the pilot oil configuration differ from previous models?

   A:​ This valve uses internal pilot supply (from main P) and external pilot drain (to Y port). You must connect the Y port directly to the tank​ with a dedicated line (max backpressure 30 bar). This configuration is simpler than external supply but requires careful management of the external drain line.

3. Q: Does this valve have a pressure reducing valve?

   A:​ No.​ The suffix /A1M​ indicates it does not​ include the /D3​ option (integrated pressure reducing valve). The pilot pressure is taken directly from the main system pressure. If system pressure fluctuates widely, consider a model with /D3​ for stable pilot operation.

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:​ Ensure the external pilot drain (Y port) is connected directly to the tank with minimal backpressure​ (max 30 bar). High backpressure on Y can cause the pilot valve to malfunction. Since there is no integrated pressure reducer (/D3), ensure your system pressure is stable or provide an external pressure-reducing valve if needed.