Komatsu PC200-8M0, Shop Manual

Page: 291 / 1254

SEN06123-00
PC200, 200LC, 220, 220LC-8M0 10-600
25
600 Electrical system
Electrical control system
1) Swing lock and swing holding brake func-
tion
q
The swing lock function (manual) is used to
lock machine from swinging at any position.
The swing holding brake function (automatic)
is used to prevent hydraulic drift after the
machine stops swinging.
q Operation of swing lock switch and swing lock/
holding brake
Swing holding brake cancel switch
q If the controller, etc. has a problem, the swing
holding brake does not work normally, and the
machine cannot swing, the swing lock can be
reset with the swing holding brake cancel
switch.
q Even if the swing holding brake cancel switch
is turned on, if the swing lock switch is placed
in the ON position, the swing brake is not
released.
q If the swing lock is reset, only the hydraulic
brake is applied by the safety valve. Note that
if swinging is stopped on a slope, the upper
structure may swing by its gravity.
2) Quick hydraulic oil warm-up function when
swing lock switch is turned on
q
If swing lock switch (2) is turned on, the pump
cut-off function is cancelled and the relief pres-
sure rises from 34.8 MPa {355 kg/cm
2
} to 37.2
MPa {380 kg/cm
2
}.
If the work equipment is relieved under this
condition, the hydraulic oil temperature rises
quickly and the warm-up time can be short-
ened.
Lock
switch
Lock
lamp
Function Operation
OFF OFF
Swing
holding
brake
If swing lever is set in neu-
tral, swing brake operates
in about 5 sec. If swing
lever is operated, brake is
released and machine can
swing freely.
ON ON
Swing
lock
Swing lock operates and
machine is locked from
swinging. Even if swing
lever is operated, swing
lock is not reset and
machine does not swing.
Swing
holding
brake cancel
switch
ON
(when controller has
trouble)
OFF
(when controller is
normaly)
Swing lock
switch
ON OFF ON OFF
Swing brake
Swing
lock is
turned on.
Swing
lock is
canceled.
Swing
lock is
turned on.
Swing
holding
brake is
turned on.