Johnson Controls SABROE Unisab III Control, Инструкция по эксплуатации

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Engineering manual - UniSAB III 1.10.8
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001930 en 2021.06
Compressor control and surveillance
3.4 Compressor control - reciprocating compressors
3.4.1 Start sequence
There is no particular starting up sequence for reciprocating compressors. However, some alarms are
delayed at start-up.
Alarm surveillance
During start the following alarms are delayed:
Low oil pressure 60 sec.
High oil pressure 20 sec.
Low suction gas superheat 20 sec.
High suction gas superheat 300 sec.
Low/high oil temperature 300 sec.
Low discharge gas superheat 300 sec.
Low/high intermediate discharge
temperature 300 sec.
See also section 6.5 Timers .
The following descriptions of the various functions must be compared with the wiring diagrams where
the activating connections are included.
3.4.2 Oil return
The solenoid valve for oil return from the oil separator/oil reservoir to the compressor will be open when
the compressor starts and an ON signal is issued to one digital input (or for two-stage compressors two
digital inputs).
For one-stage compressors, only the digital input for high pressure oil return is used. In this case, the in-
put must be ON before the digital output oil return is set.
For two-stage compressors where both the LP and HP part may have their own oil separator, the digital
inputs
intermediate pressure oil return and high pressure oil return are used. In this case, both inputs
must be ON before setting the digital output for oil return .
The opening of the solenoid valve (s) for oil return can be combined with an adjustable time delay. At
compressor start the output(s) for oil return is/are not opened until the time set in the
Oil return timer has
expired. The time delay function will be disconnected if the timer Oil return is set for 0 seconds or when
the digital inputs for intermediate and high pressure oil return are OFF.
The time delay Oil return is set in the timer picture Setup/Timers/Timer setup .
3.4.3 Start unloading system for TCMO 28 compressor
TCMO 28 reciprocating compressors have a unique unloading system which ensures low starting torque
and a correct balance between high and low pressure cylinders during part load. When the compressor
is stopped during start-up and at loading stages below or at 50%, a hot gas bypass valve “B” is activated
to ensure this. See information sheet for outputs in the wiring diagrams.
3.4.4 Additional steps on SMC compressors
From SMC 104 to SMC 108 the first capacity step is divided in two so that the compressor starts on one
cylinder. The other cylinder is used to connect changes in capacity stages. SMC 112 and 116 starts on
two cylinders and the other two are used to connect changes in capacity steps. See the wiring diagrams.
Please note that compressors with additional steps do not start totally unloaded but on one and
two cylinders respectively.