SUN HYDRAULICS
FMDAMBN812N

This valve is a 3-way, meter-in, electro-proportional throttle. The flow path, unenergized, has the supply blocked at port 1 and port 2 is drained to tank at port 3. Energizing the coil generates a closing force on the spool, creating a metering orifice in the 1 to 2 direction that is proportional to the coil command current. The valve self-compensates in the 1 to 2 direction and with the addition of an external compensator will provide pressure compensated flow control.

Flow in the 2 to 3 direction is not proportional and is limited in the interest of increased resolution and capacity. Flow capacity in the 2 to 3 direction is about 1.5 gpm (6 L/min). This valve is meant to be used in a circuit that has a separate passage to tank such as a cushion lock circuit. Two FMDA's in conjunction with a cushion lock circuit create a meter-in/meter-out 3 position 4-way.

• Note: Flow in the 2 to 3 direction is limited to about 1.5 gpm (5 L/pm).
• The transition between positions is closed.
• Using 2 3-ways to create a 4-way allows one to choose existing flow ranges instead of cutting a special spool.
• These valves may be pressure compensated by an external, modulating, logic element. Use LR_C-XHN for a bypass circuit or LP_C-XHN for a restrictive circuit.
• The valve provides a degree of self-compensation and may be used as a flow control. To increase the accuracy of flow control, an external, modulating, logic element can be used to maintain a constant flow over a wider range of flows and pressures. See performance curves for additional information.
• All ports will accept 5000 psi (350 bar).
• On models equipped with the D or L control, the detent mechanism in the manual override is meant for temporary actuation. The D, E, L and T manual control assemblies have a mechanical life expectancy of approximately 7,000 cycles.
• The momentary/twist override option "E" allows the operator to shift the valve by twisting the manual override clockwise 90 degrees.
• Coils are interchangeable with Sun's other full flow, solenoid-operated valves and can be mounted on the tube in either direction.
• For optimum performance, an amplifier with current sensing and adjustable dither should be used. Dither should be adjustable between 100 - 250 Hz.
• Incorporates the Sun floating style construction to minimize the possibility of internal parts binding due to excessive installation torque and/or cavity/cartridge machining variations.