Product description
2.4
Control devices
Page 24
Operating instructions for S 40-3...S 150-3 series screw compressors
Controlled operation
(frequency control)
If the pressure has dropped below the switch-on pressure p
min
the compressor
starts and operates in load operation.
Once the operation pressure p
target
has been exceeded the control is activated
and reduces the speed.
If the pressure has dropped below the operating pressure p
target
the control is
activated and increases the speed.
Upon reaching the switch-off pressure p
max
the compressor switches to idling-
operation.
The settings for p
min
and p
max
are effected by the parameterisation of the BASIC/
FOCUS.
For the BASIC control the setting for p
target
is effected at the potentiometer R3
in the compressor switch cabinet.
For the FOCUS control the setting for p
target
is effected via parameterisation of
the control.
Short operating times
2.4 Control devices
Operating pressure
transmitter
The operating pressure transmitter (1) controls the operation of the compres-
sor within the set switching limits.
Fig. 2.3: Operating pressure transmitter
WARNING!
During short operating times, the compressor does not reach its operating
temperature. It operates below the dew point. The condensate generated
due to physical causes mixes with the oil. The lubricating ability of the oil is
reduced. This leads to damage to the air end. It is of utmost importance to
consult BOGE if you operate your system with short operating times.
Switch-on pressure p
min
If the network pressure drops
to the set switch-on pressure
p
min
, the compressor switches
on.
Switch-off pressure p
max
If the network pressure in-
creases to the switch-off
pressure p
max
, the compres-
sor either switches off (inter-
mittent operation) or switches
to idling operation (continu-
ous operation).
