Download Operating instructions

Product description
2.4
Control devices
2.4 Control devices
Operating pressure
transmitter
The operating pressure transmitter (1) controls the operation of the compressor within the set switching limit.
Switch-on pressure pmin
If the net pressure drops to
the set switch-on pressure
pmin, the compressor switches
on.
Switch-off pressure pmax
If the net pressure increases
to the switch-off pressure
pmax, the compressor either
switches off (intermittent operation) or switches to idling
operation (continuous operation).
Fig. 2.3: Operating pressure transmitter
Proportional controller
(option) (not with SLF)
The proportional controller is an additional control device intervening in the sequences of the intake regulator.
The intake regulator only opens as far as necessary to supply the current compressed air requirement. Thus the compressor saves compression energy.
A compressor with proportional controller is able to supply its ’delivered quantity variable between 0% and 100%. However, the energy consumption does
not reduce accordingly. Therefore, a control is only practical between 50% and
100% of the delivered quantity.
The proportional controller is factory set to a delivered quantity between 50%
and 100% of the compressor capacity.
The proportional controller closes when the desired delivered quantity has
dropped below 50% of the compressor capacity. The compressor then operates in idling operation (continuous operation) or switches off (intermittent operation).
2.5 Safety and monitoring devices
General
The safety devices guarantee a high degree of operational safety, in connection with the BOGE monitoring system.
When one of the safety devices responds, the control system reacts as follows:
Page 16
–
The compressor is immediately switched off.
–
A flashing fault number in the left field of the display indicates the cause of
the fault.
BOGE Operating instructions for SL 270...SL 481 series screw compressors