HOSE AS 8X9941 - Caterpillar

Illustration 1 g03808876
Machine General Information
The propulsion control system contains an electrical portion, a hydraulic portion, and a mechanical portion. The electrical portion is made up of an electronic control module (ECM) and input and output devices. The hydraulic portion consists of two closed-circuit hydrostatic drive loops. The mechanical portion is comprised of a single-speed, planetary final drive which drives each track.In each hydrostatic drive loop, the machine ECM controls a variable-displacement propulsion pump. This pump drives a two-speed propulsion motor. Each motor drives a single-speed, planetary final drive. The final drives transfer power from the propulsion motors to the tracks. The planetary final drives have spring-applied, hydraulically released parking brakes. Charge pumps supply oil pressure which releases the brakes. The propulsion pumps supply oil pressure to engage the shifting mechanism in the two-speed propulsion motors.The electronic control system monitors the machine and monitors engine operating conditions. The control system determines if an output signal should be sent to the pump drive solenoids. The propulsion system is controlled through open-loop logic. The system prevents the machine from moving under the following conditions.
The travel direction switch is out of the NEUTRAL position when the machine is started.
The parking brake is engaged.
The operator is not standing on the operator platform.
The propulsion speed dial is in the minimum position.
The E-stop switch is in the STOP position.