3. DRAIN CIRCUIT Travel motor Swing motor From return line Main pump Turning joint Dr#, dr# Drain filter Dr Hydraulic oil tank Dr Check valve 1.5kgf/cm 2 900L3CI02 Besides internal leaks from the motors and main pump, the oil for lubrication circulates. These oil have to be fed to the hydraulic tank passing through drain filter and full flow filter in the hydraulic tank. When the drain oil pressure exceed 1.5 kgf/cm 2 (21 psi ), the oil returns to the hydraulic tank directly. 1) TRAVEL MOTOR DRAIN CIRCUIT Oil leaking from the right and left travel motors comes out of the drain ports provided in the respective motor casing and join with each other.
These oils pass through the turning joint and return to the hydraulic tank passing though a drain filter. 2) SWING MOTOR DRAIN CIRCUIT Oil leaking from the front and rear swing motors come out of the drain ports provided in the respective motor casing and join with each other and return to the hydraulic tank passing through a drain filter. 3) MAIN PUMP DRAIN CIRCUIT Oil leaking from main pump come out and return to the hydraulic tank passing through a drain filter. 3-4