HOSE AS 9V8970 - Caterpillar

Solenoids
Illustration 1 g01114964
Transmission Pilot Supply solenoidFree-Fall Clutch solenoidLeft-Hand Forward Pump solenoidLeft-Hand Reverse Pump solenoidRight-Hand Forward Pump solenoidRight-Hand Reverse Pump solenoidBoom Raise solenoidBoom Lower solenoidHook Raise solenoidHook Lower solenoidFree-Fall Clutch Backup solenoidHook Motor solenoidDead Engine Counterweight solenoidCounterweight Extend solenoidCounterweight Retract solenoid
Illustration 2 g01340348
Implement Shutoff solenoidEach of these solenoid valves is designed to control the pilot pressure to the main control valve. The transmission pilot supply solenoid then controls the rate of flow of the hydraulic oil to the implement circuit. The pilot solenoid valve is used for the following functions: free-fall clutch, free-fall clutch backup, boom raise, boom lower, hook raise, hook lower, hook motor, counterweight extend and counterweight retract. The solenoids modulate the flow of the pilot oil that cause the movement of the machine. The ECM will adjust the solenoid valves according to the request that is made by the operator through the joystick control handle. The solenoids that are used in order to control the direction and speed of the machine are: left-hand forward pump solenoid, left-hand reverse pump solenoid, right-hand forward pump solenoid and right-hand reverse pump solenoid. These solenoid valves are the proportional type of solenoid valve. The ECM uses a pulse width modulated signal (PWM) in order to vary the current to the solenoid. The solenoid receives electrical current from the ECM. The solenoid plunger then travels a distance that is in proportion to the electrical current that is sent from the ECM. The electrical current to the solenoid controls the position of the valve. The ECM can detect a failure in the solenoid circuit