TEE AIR BRAKE 5P4414 - Caterpillar

Introduction
Hydraulic Power Control System Block DiagramThe hydraulic power control system consists of a hydraulic power control, an engine speed sensor, a mode selector switch, a throttle switch, a throttle switch interface and two proportional control valves.The hydraulic power control system gets information from the engine speed sensor, the mode selector switch and the throttle switch interface. The control processes this information and sends signals out to the pump control valve solenoids. The pump control valves are opened and closed by the control to vary the amount of hydraulic oil pressure to the implement pumps. The implement pumps output is controlled by this varying pressure.The mode switch is used to select one of three modes, the modes are selected by the operator to allow for different points of machine operation. Mode 1 (Economy) allows 70 percent of the engine power to be transferred to the pumps. Mode 2 (Fine Control) allows 85 percent of the engine power to be transferred to the pumps. Mode 3 (Power) allows all available power from the engine to be transferred to the pumps.Components Description
Hydraulic Power Control
Electronic circuits within the control makes pump control decisions based on inputs from the engine speed sensor, the throttle switch interface control and the mode switch. The control inputs and outputs are connected to the machine harness wiring through a 16 contact connector.Inputs
Several types of inputs provide information to the control.Operational
The operational inputs provide information about operator requests to the control. These inputs receive information from the mode switch. This switch provides a ground to the inputs of the control.Sensor
FrequencyAt the frequency sensor input, an AC signal is present which represents the engine speed. The control measures the frequency (Hz) of the AC signal to determine the engine speed. The control uses this speed information to make hydraulic pump control decisions. AnalogAt the analog sensor input, a voltage signal is present which represents the throttle switch position. The control measures the voltage of the voltage signal to determine the throttle switch position. The control uses this throttle information to make hydraulic pump control decisions.Solenoid Output
The solenoid outputs are connected to the pump control valve solenoids. The purpose of the pump control valve solenoid is to modulate the hydraulic pressure to the implement pumps. When the control increases the current to the solenoid, hydraulic pressure to the implement pumps is increased; when the current is zero, the implement pump pressure is minimum. The control varies the current (PWM signal) to the solenoid and the solenoid modulates the implement pump pressure.Throttle Switch Interface
Electronic circuits within the interface converts the throttle switch input information into an analog signal that is output to the hydraulic power control. The interface is connected to the machine harness wiring through an eight contact connector.Inputs
The inputs provide information about the throttle switch position selected by the operator. The throttle switch provides a ground signal to the inputs of the interface.Output
The throttle signal output is an analog signal that represents the throttle switch position selected by the