R900731881 4WRKE25W8-350L-3X/6EG24ETK31/A1D3M German Rexroth proportional electromagnetic directional control valve

FAQ:

1. Spool Type (W8)

   The W8 spool​ is an overlap spool​ (positive overlap). This design minimizes internal leakage when the valve is in the center position but requires a higher deadband control signal to initiate movement. It is suitable for applications where holding position and minimal leakage are critical.

2. Control Signal (/A1)

   The /A1​ suffix (±10 V voltage input) is ideal for high-precision control systems​ (e.g., servo controllers, motion controllers) where fine resolution and fast signal response are required.

3. Pilot Oil Configuration (/6EG24ETK31)

   This valve 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 25–315 bar) and ensure the Y port drains directly to the tank with minimal backpressure (max 10 bar).

4. Integrated Pressure Reducing Valve (/D3)

   The /D3​ option includes an integrated ZDR 6​ pressure reducing valve. It ensures the pilot stage receives a stable, reduced pressure (typically around 40 bar), protecting the sensitive pilot valve from high and fluctuating main system pressures.

5. Critical Installation Notes

   • Drain Line:​ The external pilot drain (Y port) must be connected directly to the tank with a dedicated line. Backpressure on Y must be < 10 bar.

   • Cleanliness:​ Maintain high oil cleanliness (recommended NAS 1638 Class 8 or ISO 4406 20/18/15 for the main stage).

   • Pilot Supply:​ Provide clean, regulated pilot pressure to the X port.