Hitachi HISCREW V PLUS NEXT Series - Capacity Control System Explained; Capacity Control Modes

Control air flow
Operation
Mode
20US
20P
Action of
suction
throttle valve
55kW 75kW
Starting NO−COM NO−COM Opened Fully closed
Loading NC−COM NC−COM Closed Fully opened
Unloading NO−COM NO−COM Opened Fully closed
Stopping NO−COM NO−COM Opened Fully closed
Pressure
sensor
PS
COM
NO
NC
20US
COM
NC
NO
20P
55kW
Only 75kW
20P
Suction Throttle Valve Aftercooler
From air
intake filter
Orifice
To the
air end
To the discharging
air pipe
Orifice
20P：Blowoff solenoid valve 20US：Control solenoid valve PS：Pressure sensor (1)
Oil Separator
To the air end
6.2 Capacity Control System
See page 15 for changing the pressure settings and the
capacity control mode respectively.
6.2.1 Relation between Air Consumption Rate and Capacity Control System
The Vplus
HI
SCREW supports three (V, I, and P) capacity control modes. As illustrated in the table below, the capacity
control system automatically activates the most desirable mode depending on the air consumption of your plant airline.
Compressed
Air
Consumption
(%)
Operating
Frequency
（
Hz
）
Mode of Capacity Control
Pressures
to Set
Factory
Settings
(MPa)
Allowable
Setting
Range
(MPa)
Settings of
F mode
30 to 105 40 to 142
① V-mode:
CPCS Motor Speed
Control
Target
pressure
0.7 0.45 to 0.85
F011…0 (Disable)
or
F011…1 (Enable)
3 to 30 40
② I-mode:
Online/Offline Control
with Blowoff
Cutout
pressure
0.78
Target pressure +
( 0.02 to 0.08)
F011…0 (Disable)
or
F011…1 (Enable)
Cutin
pressure
0.7
Target pressure
0 to 3
Motor
OFF
③ P-mode:
Automatic Motor
Stop/ Restart Control
Motor restart
pressure
0.6
0.45 to
Target pressure
F011…0 (Disable)
30
6. SYSTEM OF EACH COMPONENT [Capacity Control System]