GEA Grasso - Page 42

Grasso
Refri
g
eration Division
GRASSO SYSTEM CONTROL
Chap. 2 - 6 638660E_chapter2.doc 01.2004/1
2.5 Switch off sequence
2.5.1 Switching off sequence in the normal case for booster, single- and two stage compressor packages
Stop command
Output — compressor motor on
Decrease of capacity
Minimum capacity reached
Figure 2.6, Switching off sequence in the normal case (booster, single- and two stage)
•
If
(1) Stop command
→
Then
(3) Decrease capacity
•
If
(4) Minimum capacity reached
→
Then
Reset the actuating signals (2) and (3)
2.5.2 Switching off sequence in case of an alarm for booster, single- and two stage compressor packages
Alarm generated
Output — compressor motor on
Release of capacity control system
Figure 2.7, Switching off sequence in case of an alarm (booster, single- and two stage)
•
If
(1) Alarm generated
→
Then
(2) Reset the actuating signal compressor motor on
→
Then
(3) De-energise capacity solenoid valves