6.3 Solenoid Operated Valves
Describe a solenoid operated valve and identify its purpose in an electrically controlled system
Describe the similarities and differences between a solenoid operated valve and a contactor
Differentiate between the terms NO and NC as applied to electrical switches and valves
Draw the hydraulic schematic symbol for a spring offset, 2 position, four way, solenoid operated valve with a cross connect in the deactivated state and a straight through in the activated state
Draw the electrical schematic symbol for the coil of a solenoid operated valve
Describe a solenoid and discuss its function and purpose inside a solenoid operated valve
Describe the purpose of the drain port inside a solenoid operated hydraulic valve
Describe the purpose of a manual override for a solenoid operated valve and draw its schematic symbol
Differentiate between the applications of closed, tandem, float, and open center 3 position valves
Describe the problems associated with the simultaneous activation of both solenoids for a double solenoid valve and discuss the means of preventing this from occurring
Differentiate between electrically held and detented solenoid operated valves
Describe the components of a typical solenoid operated valve and identify their purpose
Define and differentiate between rated voltage, pickup voltage, hold in voltage, and dropout voltage
Describe why a 120V AC coil cannot be used with 24V DC
Differentiate between inrush and sealed in current
Describe why a means of voltage spike suppression must be used for certain coils
Discuss points of inspection and maintenance procedures for solenoid operated valves
Describe shift limit characteristics for solenoid operated valves
Define both “rated flow” and “maximum inlet pressure” for solenoid operated valves
Describe both the “pressure drop for different flow rates” and “operating limits” performance curve for solenoid operated valves
Describe leakage, fluid compatibility, and required filtration specifications for solenoid operated valves
Describe a variable solenoid operated valve and discuss its application for a hydraulic system
Describe a piggyback valve and discuss its application for a hydraulic system
