PILOTSYSTEM

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PILOTSYSTEM

The oil delivered from the pilot pump performs the following main functions. -Provides pilot oil pressure to the pilot control valves for implements, swing and travel to perform machine operations. -Creates pilot oil pressure to control the output flows of the main pumps. -Creates pilot oil pressure to automatically operate the control devices.

The pilot circuit is classified into the following circuits and each circuit performs one of the above functions.

-pilot control valve circuit - power shift pressure system -pressure switch circuits - straight travel valve circuit -swing parking brake - boom priority -swing priority - automatic travel speed change

This section of the presentation will cover the pilot manifold, the implement joysticks, and the travel pilot valves.

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Agear-type pilot pump (1) provides oil flow to the pilot system. The pilot pump is mechanically connected to the drive pump.

The oil delivery from the pilot pump flows through the pilot oil filter (2) and into the components in the pilot system.

The pilot relief valve (3) is located on the mounting base for the pilot oil filter. The pilot relief valve limits the pressure in the pilot system. The pilot relief valve setting is adjustable.

Pilot system pressure can be checked at the test port (4) on the right side of the filter base. Next to the pilot pressure test port is the pilot system S•O•S port (5).

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The filter element in the pilot oil filter removes contaminants from the pilot oil.

If the pilot oil is extremely cold or if the flow of pilot oil through filter element becomes restricted by contaminants, the oil bypasses the filter element through the bypass relief valve.

The bypass relief valve is built into the base for the pilot oil filter.

The pilot oil flows from the pilot pump to the inlet port. When the pressure in the pilot oil system reaches the pressure setting of the pilot relief valve, part of the pilot oil flow is returned to the hydraulic tank through the port. The pressure of the pilot system oil in outlet lines is equal to the pressure setting of the pilot relief valve.