Komatsu PC200-8M0, Shop Manual

Page: 285 / 1254

SEN06123-00
PC200, 200LC, 220, 220LC-8M0 10-600
19
600 Electrical system
Electrical control system
1) LS control function
q
Depending on the operation condition of the
actuator, this function changes the pressure
output from the LS-EPC valve to LS valve to
change the change point (LS set differential
pressure (DLS)) of the pump discharge in the
LS valve.
q By this operation, the start-up time of the pump
discharge is optimized and the composite
operation and fine control performance is
improved.
2) Cut-off function
q This function increases PC-EPC current (J) to
reduce the flow rate in the relief state, improv-
ing fuel consumption.
3) 2-stage relief function
q
The relief pressure in the normal work is 34.8
MPa {355 kg/cm
2
}. If the 2-stage relief function
is turned on, however, the relief pressure rises
to about 37.2 MPa {380 kg/cm
2
}. By this opera-
tion, the hydraulic force is increased further.
Operating condition for turning on cut-off function
When the average value of the front and rear pressure
sensors is above 27.9 MPa {285 kg/cm
2
} with the power
maximizing function off.
The cut-off function does not work, however, while the
machine is travelling in A mode, swing lock switch is in
the “ON” position.
Operating condition for turning on 2-
stage relief function
Relief pressure
• During travel
• When swing lock switch is turned to
the ON position
• When boom is lowered
• When power maximizing function is
turned on
• When L mode is operated
34.8 MPa
{355 kg/cm
2
}
O
37.2 MPa
{380 kg/cm
2
}