Ransomes G - PLEX DP series, Service Course Manual

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8D
HYDRAULICS
SECTION 8D. TRANSMISSION
8D-17
SPECIFICATIONS
Pump: Sundstrand 15 series, 15 cc/rev. maximum, 51 litres/min @ 3400rpm engine
speed.
Charge (boost) pump: Integral part of transmission pump. 5.4cc/rev, 18.3litres/min @ 3400rpm
engine speed.
Charge relief valve: 10.3 bar (150psi)
Wheel motors: Parker Ross ME10 169cc
Optional 3WD: Parker Ross ME21 338cc
CIRCUIT DESCRIPTION
NOTE: All hydraulic pump outputs and pressures are given with the engine at maximum rpm and
with the oil at working temperature.
The foot pedal mounted on the right hand side of the platform is linked to the Transmission pump by
cable. A simple spring return system is provided to ensure the pump returns to a neutral position.
Movement of the pedal results directly in a corresponding movement of the transmission pump’s
swash-plate. The transmission system is not protected by any form of shock or relief valve. This is
considered unnecessary, as overloading the system will result in spinning the slick tyres.
Oil from the pump goes to a tee, which supplies both front motors before returning to the pump. The
front right hand motor has an oil shuttle that sets up an exchange of oil at a rate of
4 litres/minute
joining that going to the steering and lift circuit. This oil is replaced within the transmission pump by
cooler, filtered oil by the charge pump. This works whether forward or reverse drive is selected.
Third wheel drive is available as an optional accessory. A rear wheel motor of twice the capacity of
the front motors is connected in what is the return line to the pump in forward drive. As the oil has
already driven the front wheels in parallel this larger motor rotates at the same speed. A check valve
ensures that the rear motor can freewheel during severe hydrostatic braking on steep descents or
when reversing.