Grasso
Refrigeration Division
GRASSO SYSTEM CONTROL
01
.200
4
/
1
638660E_chapter2.doc Chap. 2 - 11
2.7.1
Oil system monitor of piston compressor packages
The oil system monitor is responsible for monitoring the functionality of the oil system. The package is switched
off if alarms occur.
The difference between the oil pressure and the crankcase pressure is monitored. In case no crankcase pressure
is measured, the suction pressure is used in stead.
2.7.1.1
Switching sequence in the normal case
Start conditions fulfilled
Unloaded start
Output — compressor motor on
’Oil dif press’ OK
’Oil dif start’ timer active
’Oil dif run’ timer active
’Low oil differential pressure’ alarm
Figure 2.13, Oil system monitor in the normal case
A..
During start up
B..
Brief lowering of the oil differential pressure during running
•
If
(1)
Start conditions fulfilled
→
Then
(2)
Set the actuating signal ’Unloaded start’
→
Then
(3)
Output — compressor motor on
•
If
(3)
Output — compressor motor on equals 1
→
Then
(5)
Start ’Oil dif start’ timer
•
If
(4)
’Oil dif press’ OK equals 0
and
•
If
(5)
’Oil dif start’ timer expired
→
Then
(6)
Start ’Oil dif run’ timer
If the oil differential pressure is OK again within the appropriate delay time, there is no alarm shutdown.
Summary of Contents for Grasso
Page 4: ......
Page 8: ......
Page 9: ......
Page 10: ......
Page 12: ......
Page 32: ......
Page 33: ......
Page 34: ......
Page 73: ......
Page 74: ......
Page 76: ......
Page 84: ......
Page 85: ......
Page 86: ......
Page 88: ......
Page 95: ......
Page 96: ......
Page 98: ......
Page 109: ......
Page 110: ......
Page 112: ......
Page 134: ......
Page 135: ......
Page 136: ......
Page 138: ......
Page 147: ......
Page 148: ......
Page 154: ......
Page 155: ......
Page 156: ......
Page 164: ......
Page 165: ...02 04 Master_Backpage doc 1 ...
Page 166: ......