Johnson Controls SABROE Unisab III Control User Manual

Low oil pressure 45 sec.
High filter diff. pressure 600 sec.
Low superheat 300 sec.
High superheat 300 sec.
Low/high oil temperature 300 sec.
The delayed alarms are described in section 6.5. Timers.
Stopping sequence
When a SAB 193-233-283-355 compressor stops, Unisab III will attempt to move the capacity
slide below 5% position. The solenoid valves for decreasing capacity and Vi position are acti-
vated for maximum 300 seconds. If the capacity slide is not below 5% within the 300 seconds
a Capacity error shutdown will be issued.
Balance piston for SAB 355
For SAB 355, the AUX output is dedicated for control of the balance piston. Choose the AUX
output to be activated At max. cap. in the menu Compressor control – user functions and set
the Signal high limit to 70% referring to slide capacity.
3.3.20 SABCube 109, 133 and 159
The SABCube compressors are frequency regulated screw compressors without capacity slide
but with automatic Vi-control. The compressors have no oil pump.
Starting sequence
Once the compressor has received permission to start, Unisab III will send a start signal to
the frequency converter and to the internal water cooling pump.
When the compressor starts up, the SSSTV valve will close in order to reduce the internal
suction pressure and quickly increase the oil pressure. When the timer Start unload has run
out the Start-up limiter is activated and the timer Max. start-up time is started.
The SSSTV valve is kept closed until the oil pressure is above the low alarm curve Y + a Neu-
tral zone (NZ
oil,rel
) and the suction pressure is below high alarm limit for internal suction
pressure - a Neutral zone (NZ
suct,int
).
Speed will remain at 1,000 rpm until the oil pressure is above the low alarm curve Y and the
internal suction pressure is below high alarm limit for internal suction pressure.
If the timer Max. start-up time runs out before the oil and suction pressure is inside the alarm
limits, the compressor is stopped with a shutdown.
After this forced start-up period where oil and suction pressures are inside the alarm limits,
the compressor is now in normal operation. The SSSTV limiters for High torque, high internal
suction pressure and low oil pressure will now be active too.
The default setting for timer Start unload is 15 seconds and for Max. start-up time it is 600
seconds.
Alarm surveillance
During start the following alarms are delayed:
Low oil pressure 15 sec.
High filter diff. pressure 300 sec.
Low superheat 300 sec.
High superheat 300 sec.
Low/high oil temperature 300 sec.
Compressor control and surveillance
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Engineering manual - Unisab III 1.10
001930 en 2014.09

Johnson Controls SABROE Unisab III Control Specifications

General

Brand	Johnson Controls
Model	SABROE Unisab III Control
Category	Control Systems
Language	English