SYSTEM / Control System

Purpose: The High-Low selection control controls the HST motor displacement angle according to the selected speed.

Operation:

Displacement Angle Control of HST Motor

1. When the HST control unit detects the machine speed, it computes the most suitable HST motor displacement angle.

2. The current equivalent to the computed displacement angle operation is supplied to the EP motor solenoid valve of the HST motor and changes the displacement angle.

3. The HST motor displacement angle is controlled by repeating step 1 to step 2.

NOTE: The speed selection is carried out by the High-Low selector switch. When the Low mode is selected, the signal of the selected speed (Low mode) is sent to the HST control unit.

When Low mode is selected:

• The ON signal is sent to the HST control unit from the High-Low selector switch.

• The HST motor displacement angle is controlled among A-B-C and the machine speed increases (decreases).

When High mode is selected:

• The OFF signal is sent to the HST control unit from the High-Low selector switch.

• The HST motor displacement angle is controlled among A-B-D and the machine speed increases (decreases). T4FC-02-01-101