MMD Equipment 185S-5C2 part 1 - Manual (Page 35)

4. Operation
4-17
[Function of AUTO IDLE (Purge control)]
Function Conditions of “ AUTO IDLE” lamp
① First engine speed drops to the minimum
speed by speed regulator, owing to
reduction of air consumption. Later the air
consumption is reduced further, the
unloader valve gradually closes and intake
negative pressure increases. In this stage,
the pressure sensor detects the intake
negative pressure. Then when the intake
negative pressure becomes higher than the
set pressure, the “AUTO IDLE” lamp
flickers at short intervals.
Lamp flickers at short intervals.
② When this condition continues for a
certain time, the solenoid valve (SV1)
functions to start purge mode operation.
Consequently, the pressure inside
separator receiver tank drops and reduces
the power of compressor air end. In this
stage, the lamp “AUTO IDLE” flickers at
longer intervals.
Lamp flickers at longer intervals.
③ Next, when the pressure for load down to
the purge releasing pressure owing to the
increase of air consumption, the solenoid
valve (SV1) operation gets “OFF” and it is
transferred to normal operation. In this
stage, the lamp “AUTO IDLE” goes on.
Lamp goes on.
[Standard set values prior to delivery ex-works ]
Item
Setting
knob
Set prior to delivery
ex-works
Setting range
Purge releasing pressure VR3 80 psi (5.5bar) 50-95 psi (3.5 – 6.6bar)
Purge starting rated of suction
pressure
VR2 30％ 0 - 80%
Timer for purge mode operation VR1 10 seconds 10 - 112 seconds