On the solenoid bank, each of the solenoid valves separately controls the feed of high pressure servo air to a single pneumatic valve. The valve is actuated by selectively energizing the corresponding solenoid to allow servo air to the servo port of the valve. To return the valve to its fail-safe position, the solenoid is de-energized to vent the servo port of the valve to ambient.

The solenoid bank is designed with an inlet port, a single servo line to each of the pneumatic valves, and independent vent passages for each solenoid.

The solenoids are two-stage pilot valves and are normally open with the solenoid de-energized, allowing high pressure supply air to the servo ports of the downstream pneumatic valves. Energizing the solenoid blocks high pressure air supply and simultaneously vents the pneumatic valve servo chamber to atmosphere, closing the respective pneumatic valve.

The Parker two-stage solenoid is designed to provide fast response times. The electrical configuration is a dual-coil redundant design providing an isolated circuit topology housed in a single package. Each coil is independent and identical in function.
• Designed for high vibration levels
• Uses aluminum alloy manifolds for light weight
• Designed for high-temperature environments
• Design architecture allows easy selection of two to six solenoid valves

APPLICATIONS: Commercial aircraft engines

FEATURES AND ATTRIBUTES:
• Low leakage: Total max external leakage for all solenoids combined. All solenoids, energized or de-energized, will not exceed the flow through of an equivalent orifice of effective area of 0.001 in2
• Fail-safe position: closed, engine running; closed, engine not running
• Pulse width modulation (PWM) current control mode (3.12 khz)
• Pull-in current: 150 milliamps (mA) max
• Hold current: 100 mA max
• Drop-out current: 5 mA min per coil, 10 mA min for both coils
• Coil resistance: 69.5 ±5 ohms at 68°f (20°c)
• No electromagnetic frequency (emf) suppression diodes are integrated into the solenoid bank
• Bonding resistance:
     o 2.5 megohms (MOhms) maximum between external case and mounting surface (new unit)
     o 5.0 MOhm maximum between external case and mounting surface (returned unit)
• Dielectric strength:1000 VAC @ 60 hz for one-minute coil-to-coil and each coil-to-case

OPTIONAL FEATURES:
Solenoid bank design architecture allows easy selection of two to six solenoid valves.