D155AX-5 komatsu (EN)

Fan circuit To EPC valve input port To fan motor Fan pump To drain EPC valve Fan motor Bleed plug Fan guard Page 2 D155AX-5 Hydraulic fan circuit JETT000200 Prepared by J. Ghesquiere

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EPC valve Safety valve EPC valve ODi1l5 5cAoX-o5 ler outlet Oil cooler inlet To tank Hydraulic fan circuit Page 3 To cooler and tank JETT000200 From fan pump Prepared by J. Ghesquiere ODi1l5 5cAoX-o5 ler outlet Hydraulic fan circuit JETT000200 From fan pump Prepared by J. Ghesquiere

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Fan pump Function The rotation and torque of the engine are transmitted to the shaft of this pump and converted into hydraulic energy in this pump. This pump discharges the pressurized oil according to the load. Radiator The discharge of this pump can be changed by changing the swash plate angle in it. Motor Engine Water Temp. To Fan motor Pump Controller Oil Temp. PTO Drain Fan speed Current send D155AX-5A Pump charge D155AX-5B 1050rpm from controller from controller Current send 450rpm Water temp' : 95 ° P/L Oil temp' : 107 ° Water or P/L oil temp' EPC Pilot pressure Page 4 D155AX-5 Hydraulic fan circuit JETT000200 Prepared by J. Ghesquiere

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COOLING FAN PUMP [No.1] A: Drain side B: Pump discharge pressure input side Fan pump C: EPC output pressure received D: EPC output pressure Swash plate angle Function The servo valve controls the  current input to the EPC valve and the swash plate angle of the pump so that they will be related as shown in the figure. Servo pressure Big The relationship between the input  current to the EPC valve and the output pressure of the EPC valve Cooling fan rotation is as follows.

High Oil or Water EPC Servo Swash plate Pump flow Fan speed Tem'p Current(A) Pressure Angle ( Q ) ( rpm ) Low High High Small Small Slow Oil or Water Tem'p Low EPC Current(A) High Servo Pressure High Swash plate Angle Small Pump flow ( Q ) Small Fan speed ( rpm ) Slow High Low ---- Low Low High Big Big Page 5 Big Big Fast Fast JETT000200 Prepared by J. Ghesquiere D155AX-5 ( Out of order ) Hydraulic fan circuit

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