SYSTEM / Control System Overrunning Control (HST Motor) Purpose: When the machine speed is exceeds the allowable maximum speed, it forcibly decreases the machine speed within the speed range. Operation: 1. The HST control unit computes the machine speed on the basis of the signal from the speed sensor. 2. When the computed machine speed exceeds the allowable maximum speed, the HST control unit controls the motor to make displacement angle larger. Therefore, the machine speed decreases forcibly. 3. When the computed machine speed decreases within the speed range, the HST control unit releases the overrunning control and performs normal motor displacement angle control.
NOTE: When it is under overrunning control, the HST warning indicator and the service indicator blink and the buzzer souds continuously.
Displacement Angle after Control
HST Motor Displacement Angle
Displacement Angle before Control 0 Machine Speed
T2-1-8
T4FC-02-01-101
