KAESER Aircenter SX 3 User manual

Service manual
Screw compressor
Aircenter SX 3/7.5 SIGMA CONTROL BASIC
Number: 9_6945 01USE
manroland document no.:
80.95A0S–C338

Original instructions
/KKW/SSX 1.01 en 01 IBA-SCHRAUBEN-AC-MAN-SCB

1 Regarding this Document
1.1 Using the Document ......................................................................................................... 1
1.2 Additional Documents ...................................................................................................... 1
1.3 Copyright .......................................................................................................................... 1
1.4 Symbols and Identification ............................................................................................... 1
1.4.1 Warnings ............................................................................................................. 1
1.4.2 Other instructions and symbols .......................................................................... 2
2Technical Data
2.1 Nameplate ........................................................................................................................ 3
2.2 Options ............................................................................................................................. 3
2.3 Weight .............................................................................................................................. 4
2.4 Temperature ..................................................................................................................... 4
2.5 Ambient Conditions .......................................................................................................... 4
2.6 Ventilation ........................................................................................................................ 5
2.7 Pressure ........................................................................................................................... 5
2.8 Air receiver ....................................................................................................................... 5
2.9 Free air delivery ............................................................................................................... 6
2.10 Sound pressure level ....................................................................................................... 6
2.11 Motors and power ............................................................................................................ 7
2.11.1 Compressor drive motor ..................................................................................... 7
2.12 Cooling Oil Recommendation .......................................................................................... 7
2.12.1 Basic Information ................................................................................................ 7
2.12.2 KAESER Lubricants ............................................................................................ 7
2.13 Cooling oil Volume ........................................................................................................... 8
2.14 Power Supply ................................................................................................................... 8
2.15 Power supply specifications ............................................................................................. 9
2.16 Refrigeration dryer ........................................................................................................... 10
3 Safety and Responsibility
3.1 Basic Information ............................................................................................................. 11
3.2 Specified Use ................................................................................................................... 11
3.3 Improper Use ................................................................................................................... 11
3.4 User's Responsibilities ..................................................................................................... 11
3.4.1 Observe statutory and universally accepted regulations .................................... 11
3.4.2 Qualified personnel ............................................................................................. 12
3.4.3 Adherence to inspection schedules and accident prevention regulations .......... 12
3.5 Dangers ............................................................................................................................ 12
3.5.1 Safely Dealing with Sources of Danger .............................................................. 13
3.5.2 Safe Machine Operation ..................................................................................... 15
3.5.3 Organizational Measures .................................................................................... 15
3.5.4 Danger Areas ...................................................................................................... 15
3.6 Safety Devices ................................................................................................................. 16
3.7 Safety Signs ..................................................................................................................... 16
3.8 In Emergency ................................................................................................................... 18
3.8.1 Fire fighting ......................................................................................................... 18
3.8.2 Remove any compressor cooling oil from your person. ...................................... 18
3.8.3 Injury from Handling Refrigerant ......................................................................... 18
3.9 Warranty ........................................................................................................................... 19
3.10 Environmental Protection ................................................................................................. 19
4 Design and Function
4.1 Housing ............................................................................................................................ 20
4.2 Function ........................................................................................................................... 21
4.3 Refrigeration Dryer ........................................................................................................... 22
4.4 Air receiver ....................................................................................................................... 22
Contents
Number: 9_6945 01USE
Service manual Screw compressor
Aircenter SX 3/7.5 SIGMA CONTROL BASIC i

4.5 Floating relay contacts ..................................................................................................... 22
4.6 Options ............................................................................................................................. 23
4.6.1 Machine mountings ............................................................................................. 23
4.6.2 LOAD-IDLE control by remote contact ............................................................... 23
4.6.3 Microfilter ............................................................................................................ 24
4.6.4 Activated carbon filter ......................................................................................... 24
4.7 Operating modes and control modes ............................................................................... 25
4.7.1 Operating modes ................................................................................................ 25
4.7.2 Control modes .................................................................................................... 25
4.8 Refrigeration Dryer Control Modes .................................................................................. 26
4.9 Safety Devices ................................................................................................................. 27
4.10 SIGMA CONTROL BASIC Keys and Indicators ............................................................... 27
4.11 SIGMA CONTROL BASIC function .................................................................................. 28
4.11.1 Display layout .................................................................................................... 28
4.11.2 Parameters ......................................................................................................... 29
4.11.3 Messages ........................................................................................................... 30
5 Installation and Operating Conditions
5.1 Safety ............................................................................................................................... 31
5.2 Installation conditions ....................................................................................................... 31
5.2.1 Determining location and clearances .................................................................. 31
5.2.2 Ensure adequate ventilation ............................................................................... 32
5.2.3 Exhaust duct design ........................................................................................... 32
5.3 Using the Compressor to Supply A Compressed Air System. ......................................... 33
6 Installation
6.1 Safety ............................................................................................................................... 34
6.2 Reporting Transport Damage ........................................................................................... 34
6.3 Making the Compressed Air Connection .......................................................................... 34
6.4 Making the Power Supply Connection ............................................................................. 35
6.4.1 Refrigeration dryer: Connecting the transformer according to the power supply.
.............................................................................................................................
36
6.5 Connecting the condensate drain .................................................................................... 36
6.6 Options ............................................................................................................................. 37
6.6.1 Anchoring the machine ....................................................................................... 37
6.6.2 Connecting the remote contact LOAD-IDLE control ........................................... 37
7 Initial Start-up
7.1 Safety ............................................................................................................................... 38
7.2 To be noted before commissioning .................................................................................. 38
7.3 Checking positioning and operating conditions ................................................................ 39
7.4 Setting the overload protection cut-out ............................................................................ 40
7.5 Hot gas bypass valve setting ........................................................................................... 40
7.6 Pouring cooling oil into the airend .................................................................................... 42
7.7 Checking direction of rotation ........................................................................................... 43
7.8 Starting the machine for the first time .............................................................................. 43
7.9 Checking the Door Interlock Switch ................................................................................. 44
7.10 Setting the setpoint pressure ........................................................................................... 44
8 Operation
8.1 Switching on and off ......................................................................................................... 46
8.1.1 Switching on ....................................................................................................... 46
8.1.2 Switching off ....................................................................................................... 46
8.2 Switching Off in an Emergency and Switching On again ................................................. 47
8.3 Acknowledging alarm and warning messages ................................................................. 48
8.4 Setting parameters ........................................................................................................... 48
Contents
ii Service manual Screw compressor
Aircenter SX 3/7.5 SIGMA CONTROL BASIC Number: 9_6945 01USE

9 Fault Recognition and Rectification
9.1 Basic Information ............................................................................................................. 50
9.2 Alarm messages (machine stop) ...................................................................................... 50
9.3 Warning messages .......................................................................................................... 51
9.4 Other Faults ..................................................................................................................... 52
10 Maintenance
10.1 Safety ............................................................................................................................... 53
10.2 Maintenance Schedule ..................................................................................................... 53
10.2.1 Logging maintenance work ................................................................................. 53
10.2.2 Resetting maintenance interval counters ............................................................ 54
10.2.3 Regular maintenance tasks ................................................................................ 54
10.2.4 Cooling oil changing interval ............................................................................... 55
10.2.5 Regular service work .......................................................................................... 56
10.3 Cooler: Cleaning or Renewing the Filter Mats ................................................................. 56
10.4 Cleaning or Replacing the Control Cabinet Filter Mats .................................................... 57
10.5 Cooler Maintenance ......................................................................................................... 57
10.6 Air Filter Maintenance ...................................................................................................... 58
10.7 Drive Motor Maintenance ................................................................................................. 59
10.8 Maintaining the drive belts ............................................................................................... 59
10.9 Pressure relief valve checking ......................................................................................... 60
10.10 Checking the Overheating Safety Shutdown Function ..................................................... 62
10.11 Checking the cooling oil level ........................................................................................... 62
10.12 Venting the machine (depressurizing) .............................................................................. 62
10.13 Topping up the Cooling Oil ............................................................................................... 64
10.13.1 Venting the Machine (depressurizing) ................................................................ 65
10.13.2 Top up with cooling oil and test run .................................................................... 66
10.14 Changing the cooling oil ................................................................................................... 67
10.15 Changing the oil filter ....................................................................................................... 69
10.16 Changing the oil separator cartridge ................................................................................ 71
10.17 Refrigeration dryer maintenance ...................................................................................... 72
10.17.1 Cleaning the refrigerant condenser .................................................................... 72
10.17.2 Checking condensate drainage .......................................................................... 73
10.17.3 Condensate drain maintenance .......................................................................... 73
10.18 Service air receiver .......................................................................................................... 75
10.18.1 Drain condensate manually. ............................................................................... 75
10.18.2 Checking the safety relief valve .......................................................................... 75
10.19 Document maintenance and service work. ...................................................................... 76
11 Spares, Operating Materials, Service
11.1 Note the nameplate .......................................................................................................... 77
11.2 Ordering consumable parts and operating fluids/materials .............................................. 77
11.3 KAESER AIR SERVICE .................................................................................................. 78
11.4 Service Addresses ........................................................................................................... 78
11.5 Spare Parts for Service and Repair ................................................................................. 78
12 Decommissioning, Storage and Transport
12.1 Putting Out of Operation .................................................................................................. 81
12.2 Packing ............................................................................................................................ 81
12.3 Storage ............................................................................................................................. 81
12.4 Transporting ..................................................................................................................... 82
12.4.1 Safety .................................................................................................................. 82
12.4.2 Transporting with a forklift ................................................................................... 82
12.4.3 Transporting with a crane ................................................................................... 82
12.5 Disposal ........................................................................................................................... 83
Contents
Number: 9_6945 01USE
Service manual Screw compressor
Aircenter SX 3/7.5 SIGMA CONTROL BASIC iii

13 Annex
13.1 Pipeline and instrument flow diagram (P+I diagram) ....................................................... 84
13.2 Pipe and Instrument Flow Diagram (P+I diagram): MODULATING control mode ........... 90
13.3 Dimensional drawing ........................................................................................................ 96
13.4 Electrical Diagram ............................................................................................................ 98
13.5 Service Manual for Compressed Air Filter ....................................................................... 115
Contents
iv Service manual Screw compressor
Aircenter SX 3/7.5 SIGMA CONTROL BASIC Number: 9_6945 01USE

Fig. 1 Maximum relative humidity ......................................................................................................... 5
Fig. 2 Three-phase star (wye); 4 wire; grounded neutral ..................................................................... 9
Fig. 3 Three-phase star (wye); 3 wire; grounded neutral ..................................................................... 9
Fig. 4 Location of safety signs .............................................................................................................. 16
Fig. 5 Enclosure ................................................................................................................................... 20
Fig. 6 Machine layout ........................................................................................................................... 21
Fig. 7 Refrigeration Dryer ..................................................................................................................... 22
Fig. 8 Air receiver ................................................................................................................................. 22
Fig. 9 Machine mountings .................................................................................................................... 23
Fig. 10 Microfilter .................................................................................................................................... 24
Fig. 11 Activated carbon filter ................................................................................................................. 24
Fig. 12 Keys ........................................................................................................................................... 27
Fig. 13 Indicators .................................................................................................................................... 28
Fig. 14 Recommended machine placement and dimensions [in] ........................................................... 32
Fig. 15 Compressed air connection ........................................................................................................ 35
Fig. 16 Condensate drain dimensions [inch] .......................................................................................... 36
Fig. 17 Connections to SIGMA CONTROL BASIC ............................................................................... 37
Fig. 18 Hot gas bypass valve adjustment for altitude ............................................................................. 41
Fig. 19 Adjustment angle ........................................................................................................................ 41
Fig. 20 Inlet valve filling port ................................................................................................................... 42
Fig. 21 Interlock switch position ............................................................................................................. 44
Fig. 22 Switching on and off ................................................................................................................... 46
Fig. 23 Switching off in an emergency ................................................................................................... 47
Fig. 24 Acknowledging messages .......................................................................................................... 48
Fig. 25 Filter mat for the air and oil cooler .............................................................................................. 56
Fig. 26 Control cabinet ventilation grill ................................................................................................... 57
Fig. 27 Filter mat for air and oil cooler .................................................................................................... 58
Fig. 28 Air filter maintenance .................................................................................................................. 59
Fig. 29 Changing the belt ....................................................................................................................... 60
Fig. 30 Checking the cooling oil level ..................................................................................................... 62
Fig. 31 Venting the machine ................................................................................................................... 63
Fig. 32 Topping up the Cooling Oil ......................................................................................................... 65
Fig. 33 Changing the cooling oil, oil separator tank ............................................................................... 67
Fig. 34 Changing the cooling oil, oil cooler ............................................................................................. 69
Fig. 35 Changing the oil filter .................................................................................................................. 70
Fig. 36 Changing the oil separator cartridge .......................................................................................... 71
Fig. 37 Refrigeration dryer ...................................................................................................................... 72
Fig. 38 Checking condensate drainage .................................................................................................. 73
Fig. 39 Condensate drain maintenance ................................................................................................. 74
Fig. 40 Condensate drain tap ................................................................................................................. 75
Fig. 41 Testing the safety relief valve ..................................................................................................... 75
Fig. 42 Transporting with a forklift .......................................................................................................... 82
Fig. 43 Transporting with a crane ........................................................................................................... 83
List of Illustrations
Number: 9_6945 01USE
Service manual Screw compressor
Aircenter SX 3/7.5 SIGMA CONTROL BASIC v

List of Illustrations
vi Service manual Screw compressor
Aircenter SX 3/7.5 SIGMA CONTROL BASIC Number: 9_6945 01USE

Tab. 1 The levels of danger and their meaning ..................................................................................... 1
Tab. 2 Nameplate .................................................................................................................................. 3
Tab. 3 Options ....................................................................................................................................... 3
Tab. 4 Machine weight .......................................................................................................................... 4
Tab. 5 Temperature ............................................................................................................................... 4
Tab. 6 Ambient conditions ..................................................................................................................... 4
Tab. 7 Ventilation ................................................................................................................................... 5
Tab. 8 Safety relief valve activating pressure ........................................................................................ 5
Tab. 9 Air receiver: Volume ................................................................................................................... 5
Tab. 10 Safety relief valve: activating pressure ....................................................................................... 6
Tab. 11 Free air delivery .......................................................................................................................... 6
Tab. 12 Sound pressure level .................................................................................................................. 6
Tab. 13 Compressor drive motor ............................................................................................................ 7
Tab. 14 Cooling oil charge ....................................................................................................................... 8
Tab. 15 Connection data ......................................................................................................................... 9
Tab. 16 Connection data ......................................................................................................................... 9
Tab. 17 Refrigeration dryer: Model .......................................................................................................... 10
Tab. 18 Refrigeration dryer: compressed air system ............................................................................... 10
Tab. 19 Refrigeration dryer: refrigerant circuit ......................................................................................... 10
Tab. 20 Danger Areas ............................................................................................................................. 16
Tab. 21 Safety Signs ............................................................................................................................... 17
Tab. 22 Operating states under MODULATING control .......................................................................... 26
Tab. 23 Refrigeration dryer control modes .............................................................................................. 26
Tab. 24 Keys ........................................................................................................................................... 27
Tab. 25 Indicators .................................................................................................................................... 28
Tab. 26 Display ........................................................................................................................................ 28
Tab. 27 Parameters ................................................................................................................................. 29
Tab. 28 Re-commissioning after storage ................................................................................................. 39
Tab. 29 Positioning and operating conditions checklist ........................................................................... 39
Tab. 30 Altitude correction ....................................................................................................................... 41
Tab. 31 Switching off with/without run-on time. ....................................................................................... 47
Tab. 32 Alarm messages ......................................................................................................................... 50
Tab. 33 Warning messages ..................................................................................................................... 51
Tab. 34 Other faults and actions ............................................................................................................. 52
Tab. 35 Regular maintenance tasks ........................................................................................................ 54
Tab. 36 Oil change intervals lubricants ................................................................................................... 55
Tab. 37 Regular service work .................................................................................................................. 56
Tab. 38 Permissible cooling oil level under LOAD ................................................................................. 62
Tab. 39 Logged maintenance tasks ........................................................................................................ 76
Tab. 40 Consumable parts ...................................................................................................................... 77
List of Tables
Number: 9_6945 01USE
Service manual Screw compressor
Aircenter SX 3/7.5 SIGMA CONTROL BASIC vii

List of Tables
viii Service manual Screw compressor
Aircenter SX 3/7.5 SIGMA CONTROL BASIC Number: 9_6945 01USE

1 Regarding this Document
1.1 Using the Document
The service manual is part of the machine.
➤ Keep the service manual in a safe place throughout the life of the machine.
➤ Pass the manual on to the next owner/user of the machine.
➤ Ensure that all amendments received are entered in the manual.
➤ Enter details from the machine nameplate and individual items of equipment in the table in chap‐
ter 2.
1.2 Additional Documents
Included with this service manual are additional documents intended to assist in the safe operation
of the machine:
■ Certificate of acceptance / operating instructions for the pressure vessel.
Missing documents can be requested from KAESER.
➤ Make sure all documents are complete and observe the instructions contained in them.
➤ Make sure you give the data from the nameplate when ordering documents.
1.3 Copyright
This service manual is copyright protected. Queries regarding use or duplication of the documentation
should be referred to KAESER. Correct use of information will be fully supported.
1.4 Symbols and Identification
1.4.1 Warnings
Warning notices indicate three levels of danger signified by the signal word.
■ DANGER
■ WARNING
■ CAUTION
DANGER
These show the kind of danger and its source!
The possible consequences of ignoring a warning are shown here.
The word "Danger" indicates that death or severe injury can result from ignoring the instruction.
➤ The measures required to protect yourself from danger are shown here.
➤ Always read and comply with warning instructions.
Signal word Meaning Consequences of non-observance
DANGER Warns of an imminent threat of danger Death or serious injury may result
WARNING Warns of possible danger Death or serious injury are possible
1 Regarding this Document
1.1 Using the Document
Number: 9_6945 01USE
Service manual Screw compressor
Aircenter SX 3/7.5 SIGMA CONTROL BASIC 1

Signal word Meaning Consequences of non-observance
CAUTION Warns of a possibly dangerous situa‐
tion
Light injuries or material damage are possible
Tab. 1 The levels of danger and their meaning
1.4.2 Other instructions and symbols
This symbol refers to particularly important information.
Material Here you will find details on special tools, operating materials or spare parts.
Precondition Here you will find conditional requirements necessary to carry out the task.
Here conditions relevant to safety are named that will help you to avoid dangerous situations.
➤ This bullet is is placed by lists of actions comprising one stage of a task.
In lists of actions with several stages the sequence of actions is numbered.
Information that refers to only one option is marked with an indicator (e.g.: H1 means that this
section is only valid for machines with adjustable machine mountings). Option indicators used in
this service manual are explained in chapter 2.2 .
Information referring to potential problems are identified by a question mark.
The cause is named in the help text ...
➤ ... and a remedy given.
This symbol refers to important information or measures concerning environmental protection.
Further information Here, your attention is drawn to further topics.
1 Regarding this Document
1.4 Symbols and Identification
2Service manual Screw compressor
Aircenter SX 3/7.5 SIGMA CONTROL BASIC Number: 9_6945 01USE
Option H1

2 Technical Data
2.1 Nameplate
The model designation and important technical information are given on the machine's nameplate.
The nameplate is located on the outside of the machine:
■ above the cooler
or
■ on the rear of the machine.
➤ Enter data from the nameplate here as reference:
Characteristic Value
Model
Part no.
Year
Serial no.
psig
cfm
Voltage
Hz/RPM
Package FLA
Phase
HP
Wiring Diagram
FOR SERVICE, REFER TO EQUIPMENT NUMBER
Tab. 2 Nameplate
2.2 Options
The table contains a list of possible options.
➤ Enter options here as a reference.
Option Option code Exists?
Modulating control C1
LOAD-IDLE control by remote contact C16
Direct online starting C17
Microfilter F1
Activated carbon filter F2
Adjustable machine feet H1
Air-cooling K1
Transformer power supply T2
2 Technical Data
2.1 Nameplate
Number: 9_6945 01USE
Service manual Screw compressor
Aircenter SX 3/7.5 SIGMA CONTROL BASIC 3

Option Option code Exists?
Refrigeration dryer T3
Tab. 3 Options
2.3 Weight
The weight given is the maximum. Actual weights of individual machines are dependent on equipment
fitted.
SX 3 SX 7.5
Weight [lb] 628 661
Tab. 4 Machine weight
2.4 Temperature
SX 3 SX 7.5
Minimum cut-in tempera‐
ture [°F]
40 40
Typical airend discharge
temperature during opera‐
tion [°F]
150–200 150–200
Maximum airend dis‐
charge temperature (auto‐
matic safety shut-down)
[°F]
230 230
Tab. 5 Temperature
2.5 Ambient Conditions
SX 3 SX 7.5
Maximum elevation [ft] 10 000 10 000
Permissible ambient tem‐
perature [°F]
40–115 40–115
Cooling air temperature
[°F]
40–115 40–115
Inlet air temperature [°F] 40–115 40–115
Maximum relative humidi‐
ty of intake air
see figure 1 see figure 1
* Higher elevation permissible only after consultation with the manufacturer.
Tab. 6 Ambient conditions
2 Technical Data
2.3 Weight
4Service manual Screw compressor
Aircenter SX 3/7.5 SIGMA CONTROL BASIC Number: 9_6945 01USE

Fig. 1 Maximum relative humidity
TIntake air temperature [°C]
HMaximum relative humidity of intake air [%]
2.6 Ventilation
The values given are minimum guide values.
SX 3 SX 7.5
Inlet aperture Z see fig‐
ure 14 [ft]
2.2 2.2
Exhaust fan for forced
ventilation:
Flow rate [cfm] at 100 Pa.
883 1530
Tab. 7 Ventilation
2.7 Pressure
Maximum working pressure: see nameplate
SX 3 SX 7.5
Safety relief valve activat‐
ing pressure [psig]
230 230
Tab. 8 Safety relief valve activating pressure
2.8 Air receiver
Volume
SX 3 SX 7.5
Volume [gal] 70 70
Tab. 9 Air receiver: Volume
2 Technical Data
2.6 Ventilation
Number: 9_6945 01USE
Service manual Screw compressor
Aircenter SX 3/7.5 SIGMA CONTROL BASIC 5

Safety relief valve activating pressure [psig]
Maximum working pressure: see air receiver nameplate
SX 3 SX 7.5
Safety relief valve activat‐
ing pressure [psig]
160 160
Tab. 10 Safety relief valve: activating pressure
2.9 Free air delivery
SX 3 SX 7.5
FAD
at 160 psig[cfm]
Altitude: above sea level
7.77 23.66
FAD
at 160 psig [cfm]
Altitude: 3,280 ft
7.70 23.48
FAD
at 160 psig [cfm]
Altitude: 6,560 ft
7.63 23.27
FAD
at 160 psig [cfm]
Altitude: 9,840 ft
7.59 23.10
Tab. 11 Free air delivery
2.10 Sound pressure level
Operational state:
■ Nominal flow rate
■ Nominal pressure
Measurement conditions:
■ Free-field measurement to CAGI/PNEUROP PN8 NTC 2.3
■ Measurement distance: 3.3 ft.
SX 3 SX 7.5
Sound pressure lev‐
el [dB(A)]
62 66
Tab. 12 Sound pressure level
2 Technical Data
2.9 Free air delivery
6Service manual Screw compressor
Aircenter SX 3/7.5 SIGMA CONTROL BASIC Number: 9_6945 01USE

2.11 Motors and power
2.11.1 Compressor drive motor
SX 3 SX 7.5
Rated power [hp] 3.0 7.5
Rated speed [rpm] 3490 3540
Enclosure protection TEFC
Tab. 13 Compressor drive motor
2.12 Cooling Oil Recommendation
A sticker showing the type of oil filled is located near the oil separator filler.
Information for ordering cooling oil can be found in chapter 13.4.
2.12.1 Basic Information
Lubrication of an air compressor is essential to reliable operation. Carbon and varnish can form in
compressor cooling oils. These deposits block the flow of lubricant and cause excessive wear and
failure of moving parts. Contamination of the lubricant can allow the formation of acids, causing ex‐
tensive internal corrosion. Water may be condensed decreasing the lubricity.
Lubricants in rotary compressors do much more than lubricate. During the compression process, it
acts as a sealant in the airend which is important for maximum efficiency. The lubricant also absorbs
much of the heat of compression to cool the airend and reduce the temperature of the compressed
air. It’s not enough that a compressor cooling oil lubricates well, it must stand up to the heat, pressure
and contaminants that are present in every air compressor.
2.12.2 KAESER Lubricants
KAESER synthetic lubricants should be stored in a protected location to prevent contamination. Do
not re-use drums; flush and send to reconditioner.
Although the KAESER synthetic is not highly flammable, it will burn. While KAESER synthetic com‐
pressor cooling oil is less flammable than equal viscosity mineral oils, it cannot be classified as a fire-
resistant fluid. It has a flash point above 460 °F. Since the user has total control over the conditions
of the compressor lubricant, he assumes total responsibility for its safe usage.
Material Safety Data Sheets are available for each lubricant from your authorized KAESER Service
representative.
Regardless of the lubricant selected, the KAESER SIGMA lubricants will separate readily from water.
If condensate occurs it can easily be removed. Let the compressor sit so that any water can drain
back to the separator tank and separate to the bottom. See chapter 10.14 proper draining procedure.
KAESER has several lubricants available that are specially formulated to match these demands. They
feature excellent lubricity, outstanding demulsibility (ability to separate from water), and long life.
M-SERIES:
■ M-Series SIGMA compressor cooling oils are semi-synthetic lubricants.
■ M-Series SIGMA compressor cooling oils are the highest quality petroleum lubricants. M–460 is
specially blended to provide reliable performance in KAESER screw compressors.
2 Technical Data
2.11 Motors and power
Number: 9_6945 01USE
Service manual Screw compressor
Aircenter SX 3/7.5 SIGMA CONTROL BASIC 7

S-SERIES:
■ S-Series SIGMA compressor cooling oils are synthetic lubricants.
■ S-Series SIGMA compressor cooling oils are formulated from the most advanced synthetic lu‐
bricants. These ”synthetic” lubricants begin as high quality petroleum feed stock. They are then
refined, processed and purified into fluids with very consistent molecular structure. These oils are
carefully blended to produce extremely consistant lubricants with superior properties. SIGMA
synthetic lubricants feature all the advantages of both PAO and diester fluids.
■ S–460 lubricant is recommended for compressors operating in ambient temperatures between
40 °F and 105 °F.
Specialty KAESER LUBRICANTS:
■ S–680 lubricant may be used when ambient temperatures are always between 70 °F and 105 °F.
■ FG–460 synthetic hydrocarbon based food grade lubricant is designed for use in rotary screw
compressors in the application where incidental food contact may occur with the discharge air.
This lubricant meets the requirements of the FDA Regulation 21 CFR §178.3570 and is
USDA H–1 approved and NSF certified. FG–460 is approved for canning, food packing, meat and
poultry processing and other applications where incidental food contact may occur.
2.13 Cooling oil Volume
The charge of cooling oil for machines with heat recovery is increased by the volume of oil in
the heat exchanger and connecting lines.
SX 3 SX 7.5
Total charge [gall] 3.2 3.2
Topping up volume [quart]
(minimum–maximum)
0.13 0.13
Tab. 14 Cooling oil charge
2.14 Power Supply
Basic requirements
The machine is designed for an electrical supply according to National Electric Code (NEC) NEC–
670, particulary NFPA 79, edition 2007, section 4.3. In the absence of any user-specified alternatives,
the limits given in these standards must be adhered to. Consult manufacturer for any other specific
power supply.
Three-phase
Do NOT operate package on any unsymmetrical power supply. Also do NOT operate package on
power supplies like, for example, a three-phase (open) delta or three-phase star with non-grounded
neutral.
The machine requires a symmetrical three-phase power supply transformer with a WYE configuration
output as shown in Figure 2 and Figure 3. In a symmetrical three phase supply the phase angles and
voltages are all the same.
Other power supplies are not suitable.
2 Technical Data
2.13 Cooling oil Volume
8Service manual Screw compressor
Aircenter SX 3/7.5 SIGMA CONTROL BASIC Number: 9_6945 01USE

Fig. 2 Three-phase star (wye); 4 wire; grounded neutral
Fig. 3 Three-phase star (wye); 3 wire; grounded neutral
Further information Please contact authorized KAESER Service representative for options.
The electrical diagram 13.4 contains further specifications for electrical connection.
2.15 Power supply specifications
The following multi-strand copper core wires are given according to 2008 NEC 310.15, Table 310.16
for 40 °C ambient temperature.
If other local conditions prevail, like for example high temperature, the cross section should be
checked and adjusted according to 2008 NEC 110.14©, 220.3,310.15, Table 310.16, 430.6, 430.22,
430.24 and other local codes.
Dual element time delay fuses are selected according to 2008 NEC 240.6,430.52 and tables 430.52,
430.248 and 430–.250.
We strongly suggest using a separate copper conductor for the equipment GROUNDING. NEC Ta‐
ble 250.122 will point out the ”minimum size”, however, we recommend a ground conductor the same
size as the power leads, if local codes allow.
Mains voltage: 400V±10%/3/60Hz
SX 3 SX 7.5
Pre-fuse[A] 10 20
Supply 4xAWG14 4xAWG14
Consumption [A] 6.3 12
Tab. 15 Connection data
Mains voltage: 460V±10%/3/60Hz
SX 3 SX 7.5
Pre-fuse[A] 10 15
Supply 4xAWG14 4xAWG14
Consumption [A] 5.7 10.7
Tab. 16 Connection data
2 Technical Data
2.15 Power supply specifications
Number: 9_6945 01USE
Service manual Screw compressor
Aircenter SX 3/7.5 SIGMA CONTROL BASIC 9

2.16 Refrigeration dryer
Model
SX 3 SX 7.5
Model *
*Transfer data from dryer nameplate to the table.
Tab. 17 Refrigeration dryer: Model
Compressed air system
ABT 4 ABT 8
Pressure drop [psig]
(referred to 100 psig work‐
ing pressure)
1.6 1.6
Maximum permitted work‐
ing pressure [psig]
232 232
Tab. 18 Refrigeration dryer: compressed air system
Refrigerant circuit
The refrigeration dryer contains a refrigerant that is classified by the Kyoto Protocol as a fluoridised
global warming gas.
ABT 4 ABT 8
Refrigerant R 134a R 134a
Global warming potential
(GWP)
1300 1300
Charge quantity* [lb]
Maximum permitted work‐
ing pressure [psig]
261 261
Safety pressure switch:
shutdown pressure [psig]
261 261
* Read off the charge quantity from the dryer nameplate and enter it in the table.
Tab. 19 Refrigeration dryer: refrigerant circuit
2 Technical Data
2.16 Refrigeration dryer
10 Service manual Screw compressor
Aircenter SX 3/7.5 SIGMA CONTROL BASIC Number: 9_6945 01USE