Quadro Control - KAESER SM 8 Service Manual

Construction and Operation
5.5

QUADRO Control

p
max
p min
Full load
Idle
Standstill
t
p
rise
t
p
decay
Running period
Idle/
standstill period
Run ---on period
Stop point for the running period or idle / standstill period
p upper switching point
max
p lower switching point
min
t pressure rise time (the time during which the air system pressure rises
p
rise
from the lower to the upper switching point)
t pressure decay time (the time during which the air system pressure decays
p
decay
from the upper to the lower switching point)
Functional description
Two fixed periods --- the running period and idle/standstill period --- are taken as the crit-
erium for selection of the operating mode of the compressor package when the air mains
pressure reaches the upper switching point. These two periods are set according to the
maximum permissible cut ---in frequency of the compressor motor.
The running period starts every time the compressor package is switched on. It lasts as
long as the compressor motor runs and stops when the compressor package switches to
full stop.
The idle/standstill period starts every time the operating mode changes from full load to off
load running. It runs during idle and also when the compressor package is switched to
standstill after the idle period. It stops when the compressor package switches to full load.
Every switching off point is delayed by the run ---on period, during which time the com-
pressor package vents.
The following switching cycles are possible:
-
If the air systems pressure decays to the lower switching point, the compressor pack-
age switches to full load (1) irrespective of its previous operating mode. If the com-
pressor motor was at a standstill the opening of the inlet valve is delayed to allow an
unloaded compressor package start.
1 1 2 1 3 1 4 1 2 1 4 5 1 1
Time
5 --- 16