KAESER AIRTOWER 3C User manual

Operator Manual
Screw Compressor
AIRTOWER 3C–7.5C Tri-Voltage
9_6917 34 USE
manroland-document-no.:
80.95A EN F254
Manufacturer:
KAESER KOMPRESSOREN SE
96410 Coburg • PO Box 2143 • GERMANY • Tel. [phone] • Fax [phone]
http://www.kaeser.com

Original instructions
/KKW/SSXC 2.14 en Z1 SBA-SCHRAUBEN-TRI-VOLTAGE-AC-SCB
20160524 092822

1 Regarding this Document
1.1 Using this document ......................................................................................................... 1
1.2 Further documents ........................................................................................................... 1
1.3 Copyright .......................................................................................................................... 1
1.4 Symbols and labels .......................................................................................................... 1
1.4.1 Warnings ............................................................................................................. 1
1.4.2 Potential damage warnings ................................................................................ 2
1.4.3 Other alerts and their symbols ............................................................................ 2
2 Technical Data
2.1 Nameplate ........................................................................................................................ 4
2.2 Options ............................................................................................................................. 4
2.3 Weight .............................................................................................................................. 5
2.4 Temperature ..................................................................................................................... 5
2.5 Ambient conditions ........................................................................................................... 5
2.6 Ventilation ........................................................................................................................ 6
2.7 Pressure ........................................................................................................................... 6
2.8 Air receiver ....................................................................................................................... 7
2.9 Free air delivery (FAD) ..................................................................................................... 7
2.10 Cooling Oil Recommendation .......................................................................................... 7
2.10.1 Basic Information ................................................................................................ 8
2.10.2 KAESER Lubricants ............................................................................................ 8
2.11 Cooling oil charge ............................................................................................................ 9
2.12 Motor and performance .................................................................................................... 9
2.12.1 Compressor motor .............................................................................................. 9
2.13 Sound emission ................................................................................................................ 10
2.14 Power Supply ................................................................................................................... 10
2.15 Power Supply specifications ............................................................................................ 11
2.16 Refrigerated dryer ............................................................................................................ 12
2.16.1 Power supply specifications ................................................................................ 13
3 Safety and Responsibility
3.1 Basic instructions ............................................................................................................. 14
3.2 Specified use .................................................................................................................... 14
3.3 Improper use .................................................................................................................... 14
3.4 User's Responsibilities ..................................................................................................... 14
3.4.1 Observe statutory and universally accepted regulations .................................... 14
3.4.2 Qualified personnel ............................................................................................. 15
3.4.3 Adherence to inspection schedules and accident prevention regulations .......... 15
3.5 Dangers ............................................................................................................................ 15
3.5.1 Safely dealing with sources of danger ................................................................ 15
3.5.2 Safe machine operation ...................................................................................... 18
3.5.3 Organizational Measures .................................................................................... 20
3.5.4 Danger Areas ...................................................................................................... 20
3.6 Safety devices .................................................................................................................. 20
3.7 Working life of safety functions ........................................................................................ 21
3.8 Safety signs ...................................................................................................................... 21
3.9 Emergency situations ....................................................................................................... 23
3.9.1 Correct fire fighting ............................................................................................. 23
3.9.2 Treating injuries from handling cooling oil .......................................................... 23
3.9.3 Injury from Handling Refrigerant ......................................................................... 24
3.10 Warranty ........................................................................................................................... 24
3.11 Environmental protection ................................................................................................. 25
4 Design and Function
4.1 Enclosure ......................................................................................................................... 26
Contents
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AIRTOWER 3C–7.5C Tri-Voltage i

4.2 Machine function .............................................................................................................. 27
4.3 Refrigerated dryer ............................................................................................................ 28
4.4 Air receiver ....................................................................................................................... 28
4.5 Safety devices .................................................................................................................. 28
4.6 Floating relay contacts ..................................................................................................... 29
4.7 Operating panel SIGMA CONTROL BASIC .................................................................... 29
4.8 Functional description – SIGMA CONTROL BASIC ....................................................... 30
4.8.1 Display layout ..................................................................................................... 30
4.8.2 Parameter ........................................................................................................... 31
4.8.3 Messages ........................................................................................................... 32
4.9 Operating modes and control modes ............................................................................... 33
4.9.1 Machine operating modes .................................................................................. 33
4.9.2 START-STOP control ......................................................................................... 33
4.10 Refrigerated dryer control modes ..................................................................................... 33
4.11 Options ............................................................................................................................. 33
4.11.1 Machine mountings ............................................................................................. 34
5 Installation and Operating Conditions
5.1 Ensuring safety ................................................................................................................ 35
5.2 Installation conditions ....................................................................................................... 35
5.2.1 Determining location and clearances .................................................................. 35
5.2.2 Ensuring the machine room ventilation ............................................................... 36
5.3 Operating the machine in a compressed air system ........................................................ 37
6 Installation
6.1 Ensuring safety ................................................................................................................ 38
6.2 Reporting Transport Damage ........................................................................................... 39
6.3 Connecting the machine with the compressed air network .............................................. 39
6.4 Connecting the condensate drain .................................................................................... 39
6.5 Refrigerated dryer: Connecting the transformer according to the power supply. ............. 41
6.6 Making the Power Supply Connection ............................................................................. 41
6.6.1 Changing main voltage connections ................................................................... 42
6.7 Options ............................................................................................................................. 43
6.7.1 Anchoring the machine ....................................................................................... 43
7 Initial Start-up
7.1 Ensuring safety ................................................................................................................ 44
7.2 Instructions to be observed before commissioning or re-commissioning ......................... 45
7.3 Checking installation and operating conditions ................................................................ 45
7.4 Setting the overload protection relay ................................................................................ 46
7.5 Pouring cooling oil into the airend .................................................................................... 46
7.6 Starting the machine for the first time .............................................................................. 47
7.7 Setting the network setpoint pressure .............................................................................. 47
8 Operation
8.1 Switching On and Off ....................................................................................................... 49
8.1.1 Switching on ....................................................................................................... 49
8.1.2 Switching off ....................................................................................................... 49
8.2 Switching off in an emergency and switching on again .................................................... 50
8.3 Setting parameters ........................................................................................................... 50
8.4 Acknowledging alarm and warning messages ................................................................. 51
9 Fault Recognition and Rectification
9.1 Basic instructions ............................................................................................................. 53
9.2 Fault messages (machine shut down) ............................................................................. 53
9.3 Warning messages .......................................................................................................... 54
9.4 Other faults ....................................................................................................................... 55
Contents
ii
Operator Manual Screw Compressor
AIRTOWER 3C–7.5C Tri-Voltage 9_6917 34 USE

10 Maintenance
10.1 Ensuring safety ................................................................................................................ 56
10.2 Following the maintenance plan ....................................................................................... 57
10.2.1 Logging maintenance work ................................................................................. 57
10.2.2 Resetting maintenance interval counters ............................................................ 57
10.2.3 Regular maintenance tasks ................................................................................ 57
10.2.4 Cooling oil changing interval ............................................................................... 58
10.2.5 Regular service tasks ......................................................................................... 59
10.3 Clean or replace the filter mat .......................................................................................... 59
10.4 Cooler maintenance ......................................................................................................... 60
10.5 Air Filter Maintenance ...................................................................................................... 61
10.6 Compressor motor maintenance ...................................................................................... 62
10.7 Maintaining the drive belt ................................................................................................. 62
10.8 Checking the cooling oil level ........................................................................................... 63
10.9 Venting the machine (depressurizing) .............................................................................. 64
10.10 Replenishing cooling oil ................................................................................................... 66
10.10.1 Venting the machine (depressurizing) ................................................................ 67
10.10.2 Topping off with cooling oil and carrying out a trial run ...................................... 68
10.11 Changing the cooling oil ................................................................................................... 68
10.12 Changing the oil filter ....................................................................................................... 71
10.13 Changing the oil separator cartridge ................................................................................ 72
10.14 Checking the safety relief valve activating pressure ........................................................ 74
10.14.1 Checking the compressor safety relief valve ...................................................... 74
10.14.2 Checking the air receiver relief valve .................................................................. 75
10.14.3 Performing the test ............................................................................................. 75
10.14.4 Returning the machine to operational ................................................................. 76
10.15 Check the safety shut-down due to excessive airend discharge temperature. ................ 76
10.16 Testing the EMERGENCY STOP push button ................................................................. 76
10.17 Maintaining the refrigerated dryer .................................................................................... 77
10.17.1 Cleaning the refrigerant condenser .................................................................... 77
10.17.2 Maintaining the condensate drain ....................................................................... 78
10.18 Air receiver maintenance ................................................................................................. 80
10.19 Documenting maintenance and service work .................................................................. 82
11 Spares, Operating Materials, Service
11.1 Note the nameplate .......................................................................................................... 83
11.2 Ordering consumable parts and operating fluids/materials .............................................. 83
11.3 KAESER AIR SERVICE .................................................................................................. 83
11.4 Service Addresses ........................................................................................................... 84
11.5 Replacement parts for service and repair ........................................................................ 84
12 Decommissioning, Storage and Transport
12.1 Decommissioning ............................................................................................................. 87
12.2 Packing ............................................................................................................................ 87
12.3 Storage ............................................................................................................................. 87
12.4 Transport .......................................................................................................................... 88
12.4.1 Safety .................................................................................................................. 88
12.4.2 Transport with a forklift truck ............................................................................... 88
12.4.3 Transport with a crane ........................................................................................ 88
12.5 Disposal ........................................................................................................................... 89
13 Annex
13.1 Pipeline and instrument flow diagram (P+I diagram) ....................................................... 91
13.2 Dimensional Drawing ....................................................................................................... 97
13.3 Electrical Diagram ............................................................................................................ 99
Contents
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Contents
iv
Operator Manual Screw Compressor
AIRTOWER 3C–7.5C Tri-Voltage 9_6917 34 USE

Fig. 1 Maximum relative humidity of intake air ..................................................................................... 6
Fig. 2 Three-phase star (wye); 4 wire; grounded neutral ..................................................................... 10
Fig. 3 Three-phase star (wye); 3 wire; grounded neutral ..................................................................... 10
Fig. 4 Location of safety signs .............................................................................................................. 21
Fig. 5 Enclosure overview .................................................................................................................... 26
Fig. 6 Machine overview ....................................................................................................................... 27
Fig. 7 Refrigerated dryer ...................................................................................................................... 28
Fig. 8 Keys – overview ......................................................................................................................... 29
Fig. 9 Indicators – overview .................................................................................................................. 30
Fig. 10 Machine mountings .................................................................................................................... 34
Fig. 11 Recommended machine placement and dimensions [in] ........................................................... 36
Fig. 12 Compressed pipework ................................................................................................................ 39
Fig. 13 Connecting the condensate drain ............................................................................................... 41
Fig. 14 Inlet valve filling port ................................................................................................................... 46
Fig. 15 Switching on and off ................................................................................................................... 49
Fig. 16 Switching off in an emergency ................................................................................................... 50
Fig. 17 Acknowledging messages .......................................................................................................... 51
Fig. 18 Filter mat .................................................................................................................................... 60
Fig. 19 Oil cooler .................................................................................................................................... 61
Fig. 20 Air filter maintenance .................................................................................................................. 62
Fig. 21 Changing the belt ....................................................................................................................... 63
Fig. 22 Checking the cooling oil level ..................................................................................................... 64
Fig. 23 Venting the machine ................................................................................................................... 65
Fig. 24 Replenishing the cooling oil ........................................................................................................ 66
Fig. 25 Changing the cooling oil, oil separator tank ............................................................................... 69
Fig. 26 Changing the oil filter .................................................................................................................. 72
Fig. 27 Changing the oil separator cartridge .......................................................................................... 73
Fig. 28 Compressor: Checking the safety relief valve ............................................................................ 74
Fig. 29 Air receiver: Testing the safety relief valve ................................................................................. 75
Fig. 30 Testing the EMERGENCY STOP push button ........................................................................... 76
Fig. 31 Refrigerated dryer ...................................................................................................................... 77
Fig. 32 Checking the condensate drain .................................................................................................. 78
Fig. 33 Changing the service unit ........................................................................................................... 79
Fig. 34 Air receiver maintenance ............................................................................................................ 80
Fig. 35 Transporting with a forklift truck ................................................................................................. 88
Fig. 36 Transporting with a crane ........................................................................................................... 89
List of Illustrations
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Operator Manual Screw Compressor
AIRTOWER 3C–7.5C Tri-Voltage v

List of Illustrations
vi
Operator Manual Screw Compressor
AIRTOWER 3C–7.5C Tri-Voltage 9_6917 34 USE

Tab. 1 Danger levels and their definition (personal injury) .................................................................... 1
Tab. 2 Danger levels and their definition (damage to property) ............................................................ 2
Tab. 3 Nameplate .................................................................................................................................. 4
Tab. 4 Options ....................................................................................................................................... 5
Tab. 5 Weight ........................................................................................................................................ 5
Tab. 6 Temperature ............................................................................................................................... 5
Tab. 7 Ambient conditions ..................................................................................................................... 5
Tab. 8 Ventilation ................................................................................................................................... 6
Tab. 9 Safety relief valve activating pressure ........................................................................................ 7
Tab. 10 Air receiver: Volume ................................................................................................................... 7
Tab. 11 Safety relief valve: activating pressure ....................................................................................... 7
Tab. 12 Free air delivery .......................................................................................................................... 7
Tab. 13 Cooling oil charge ....................................................................................................................... 9
Tab. 14 Compressor motor ...................................................................................................................... 9
Tab. 15 Compressor drive motor rated speed ......................................................................................... 9
Tab. 16 Sound emission .......................................................................................................................... 10
Tab. 17 Supply 208V/3/60Hz ................................................................................................................... 11
Tab. 18 Supply 230V/3/60Hz ................................................................................................................... 11
Tab. 19 Supply 460V/3/60Hz ................................................................................................................... 11
Tab. 20 Refrigerated dryer: Model ........................................................................................................... 12
Tab. 21 Refrigerated dryer: Compressed air system ............................................................................... 12
Tab. 22 Refrigerated dryer: Refrigerant system ...................................................................................... 12
Tab. 23 Power supply 115V / 1 / 60Hz .................................................................................................... 13
Tab. 24 Danger Areas ............................................................................................................................. 20
Tab. 25 Safety Signs ............................................................................................................................... 21
Tab. 26 Keys ........................................................................................................................................... 29
Tab. 27 Indicators .................................................................................................................................... 30
Tab. 28 Display ........................................................................................................................................ 31
Tab. 29 Parameter ................................................................................................................................... 31
Tab. 30 Condensate line ......................................................................................................................... 40
Tab. 31 Condensate collecting line ......................................................................................................... 40
Tab. 32 Condensate collecting line: Line diameter .................................................................................. 40
Tab. 33 Voltage selection ........................................................................................................................ 42
Tab. 34 Overload protection cutout settings. ........................................................................................... 43
Tab. 35 Re-commissioning after storage ................................................................................................. 45
Tab. 36 Installation conditions checklist .................................................................................................. 45
Tab. 37 Fault messages and remedies ................................................................................................... 53
Tab. 38 Warning messages ..................................................................................................................... 54
Tab. 39 Other faults and remedies .......................................................................................................... 55
Tab. 40 Warn others that the machine is being serviced. ....................................................................... 56
Tab. 41 Regular maintenance tasks ........................................................................................................ 58
Tab. 42 Oil change intervals lubricants ................................................................................................... 59
Tab. 43 Regular service tasks ................................................................................................................. 59
Tab. 44 Permissible cooling oil level under LOAD ................................................................................. 64
Tab. 45 Logged maintenance tasks ........................................................................................................ 82
Tab. 46 Consumable parts ...................................................................................................................... 83
List of Tables
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List of Tables
viii
Operator Manual Screw Compressor
AIRTOWER 3C–7.5C Tri-Voltage 9_6917 34 USE

1 Regarding this Document
1.1 Using this document
The operating manual is a component of the product. It describes the machine as it was at the time
of first delivery after manufacture.
➤ Keep the operating manual in a safe place throughout the life of the machine.
➤ Supply any successive owner or user with this operating manual.
➤ Please insert any amendment or revision of the operating manual sent to you.
➤ Enter details from the machine nameplate and individual items of equipment in the table in
chapter 2.
1.2 Further documents
Further documents included with this operator manual are:
■ 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 provide the data from the nameplate when ordering documents.
1.3 Copyright
This service manual is copyright protected. Queries regarding use or duplication of the documenta‐
tion should be referred to KAESER. Correct use of information will be fully supported.
1.4 Symbols and labels
➤ Please note the symbols and labels used in this document.
1.4.1 Warnings
Warning notices indicate dangers that may result in injury when disregarded.
Warning notices indicate three levels of danger identified by the corresponding signal word:
Signal term Meaning Consequences of disregard
DANGER Warns of an imminent danger Will result in death or severe injury
WARNING Warns of a potentially imminent danger May result in death or severe injury
CAUTION Warns of a potentially dangerous situation May result in a moderate physical injury
Tab. 1 Danger levels and their definition (personal injury)
Warning notices preceding a chapter apply to the entire chapter, including all sub-sections.
Example:
1 Regarding this Document
1.1 Using this document
9_6917 34 USE
Operator Manual Screw Compressor
AIRTOWER 3C–7.5C Tri-Voltage 1

The type and source of the imminent danger is shown here!
The possible consequences of ignoring a warning are shown here.
If you ignore the warning notice, the "DANGER" signal word indicates a lethal or severe in‐
jury will occur.
➤ The measures required to protect yourself from danger are shown here.
Warning notes referring to a sub-section or the subsequent action are integrated into the procedure
and numbered as an action.
Example:
1.
The type and source of the imminent danger is shown here!
The possible consequences of ignoring a warning are shown here.
If you ignore the warning notice, the "WARNING" signal word indicates that a lethal or severe
injury may occur.
➤ The measures required to protect yourself from danger are shown here.
2. Always read and comply with warning instructions.
1.4.2 Potential damage warnings
Contrary to the warnings shown above, damage warnings do not indicate a potential personal in‐
jury.
Warning notices for damages are identified by their signal term.
Signal term Meaning Consequences of disregard
NOTE Warns of a potentially dangerous situation Damage to property is possible
Tab. 2 Danger levels and their definition (damage to property)
Example:
The type and source of the imminent danger is shown here!
Potential effects when ignoring the warning are indicated here.
➤ The protective measures against the damages are shown here.
➤ Carefully read and fully comply with warnings against damages.
1.4.3 Other alerts and their symbols
This symbol identifies particularly important information.
1 Regarding this Document
1.4 Symbols and labels
2
Operator Manual Screw Compressor
AIRTOWER 3C–7.5C Tri-Voltage 9_6917 34 USE

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.
The conditions relevant to safety shown here will help you to avoid dangerous situations.
➤ This symbol denotes lists of actions comprising one stage of a task.
Operating instructions with several steps are numbered in the sequence of the operating steps.
Information relating to one option only are marked with an option code (e.g., H1 indicates that
this section applies only to machines with machine mountings). Option codes used in this oper‐
ator 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 ...
➤ ... as is a solution.
This symbol identifies important information or measures regarding the protection of the envi‐
ronment.
Further information Further subjects are introduced here.
1 Regarding this Document
1.4 Symbols and labels
9_6917 34 USE
Operator Manual Screw Compressor
AIRTOWER 3C–7.5C Tri-Voltage 3
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 air receiver.
➤ Enter data from the nameplate here as reference:
Characteristic Value
Model
Part no.
Year
Serial no.
psig
cfm
Characteristic
Power supply of Compressor
Value
Voltage
Phase
Package FLA
Hz
Drive Motor FLA
RPM
HP
Characteristic
Power supply of Dryer
Value
Voltage
Phase
Package FLA
Hz
Refr. compr. FLA
Characteristic Value
Wiring Diagram
FOR SERVICE, REFER TO EQUIPMENT NUMBER
Tab. 3 Nameplate
2.2 Options
The table contains a list of possible options.
2 Technical Data
2.1 Nameplate
4
Operator Manual Screw Compressor
AIRTOWER 3C–7.5C Tri-Voltage 9_6917 34 USE

➤ Enter options here as a reference:
Option Option code Available?
Bolt-down machine feet H1
Air-cooling K1 ✓
available: ✓
not available: —
Tab. 4 Options
2.3 Weight
The values shown are maximum values. Actual weight of individual machine is dependent on
equipment fitted.
AIRTOWER 3C AIRTOWER 4C AIRTOWER 5C AIRTOWER
7.5C
Weight [lb] 628 628 639 661
Tab. 5 Weight
2.4 Temperature
AIRTOWER 3C AIRTOWER 4C AIRTOWER 5C AIRTOWER
7.5C
Minimum cut-in tempera‐
ture [°F]
40 40 40 40
Typical airend discharge
temperature during oper‐
ation [°F]
150 – 200 150 – 200 150 – 200 150 – 200
Maximum airend dis‐
charge temperature (au‐
tomatic safety shut-
down) [°F]
230 230 230 230
Tab. 6 Temperature
2.5 Ambient conditions
AIRTOWER 3C AIRTOWER 4C AIRTOWER 5C AIRTOWER
7.5C
Maximum alti‐
tude AMSL* [ft]
3000 3000 3000 3000
Permissible ambient tem‐
perature [°F]
40 – 115 40 – 115 40 – 115 40 – 115
* Higher altitudes are permissible only after consultation with the manufacturer.
2 Technical Data
2.3 Weight
9_6917 34 USE
Operator Manual Screw Compressor
AIRTOWER 3C–7.5C Tri-Voltage 5

AIRTOWER 3C AIRTOWER 4C AIRTOWER 5C AIRTOWER
7.5C
Cooling air tempera‐
ture [°F]
40 – 115 40 – 115 40 – 115 40 – 115
Intake air temperature
[°F]
40 – 115 40 – 115 40 – 115 40 – 115
* Higher altitudes are permissible only after consultation with the manufacturer.
Tab. 7 Ambient conditions
Fig. 1 Maximum relative humidity of intake air
TIntake air temperature [°F]
HMaximum relative humidity of intake air [%]
2.6 Ventilation
The values given are minimum guide values.
AIRTOWER 3C AIRTOWER 4C AIRTOWER 5C AIRTOWER
7.5C
Inlet aperture Z see fig‐
ure 11 [sq. ft.]
2.2 2.2 2.2 2.2
Extractor for forced venti‐
lation:
Flow rate [cfm] at 100 Pa.
883 1001 1236 1530
Tab. 8 Ventilation
2.7 Pressure
Maximum working pressure: see nameplate
2 Technical Data
2.6 Ventilation
6
Operator Manual Screw Compressor
AIRTOWER 3C–7.5C Tri-Voltage 9_6917 34 USE

Safety relief valve activating pressure [psi]
Maximum working pres‐
sure [psig]
AIRTOWER 3C AIRTOWER 4C AIRTOWER 5C AIRTOWER
7.5C
125 155 155 155 155
160 230 230 230 230
217 — 230 230 230
Tab. 9 Safety relief valve activating pressure
2.8 Air receiver
Volume
AIRTOWER 3C AIRTOWER 4C AIRTOWER 5C AIRTOWER
7.5C
Volume [gal] 53 53 53 53
Tab. 10 Air receiver: Volume
Safety relief valve activating pressure [psig]
Maximum working pressure: see air receiver nameplate
Maximum working pres‐
sure [psig]
AIRTOWER 3C AIRTOWER 4C AIRTOWER 5C AIRTOWER
7.5C
155 165 165 165 165
217 230 230 230 230
Tab. 11 Safety relief valve: activating pressure
2.9 Free air delivery (FAD)
FAD [cfm]:
Maximum working pres‐
sure [psig]
AIRTOWER 3C AIRTOWER 4C AIRTOWER 5C AIRTOWER
7.5C
125 12 16 21 28
160 9 13 17 24
217 — 9 13 19
FAD as per ISO 1217:2009, Annex C
Tab. 12 Free air delivery
2.10 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 11.
2 Technical Data
2.8 Air receiver
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AIRTOWER 3C–7.5C Tri-Voltage 7

2.10.1 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 ab‐
sorbs much of the heat of compression to cool the airend and reduce the temperature of the com‐
pressed 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.
2.10.2 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 condi‐
tions 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 wa‐
ter. 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 10.11 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.
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 consistent 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.
2 Technical Data
2.10 Cooling Oil Recommendation
8
Operator Manual Screw Compressor
AIRTOWER 3C–7.5C Tri-Voltage 9_6917 34 USE

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-1approved and NSF certified. FG-460 is approved for canning, food packing, meat
and poultry processing and other applications where incidental food contact may occur.
2.11 Cooling oil charge
AIRTOWER 3C AIRTOWER 4C AIRTOWER 5C AIRTOWER
7.5C
Total charge [qt.] 3.0 3.0 3.0 3.0
Topping off volume [qt.]
(minimum–maximum)
0.13 0.13 0.13 0.13
Tab. 13 Cooling oil charge
2.12 Motor and performance
2.12.1 Compressor motor
AIRTOWER 3C AIRTOWER 4C AIRTOWER 5C AIRTOWER
7.5C
Rated power [hp] 3 4 5 7.5
Protection rating TEFC TEFC TEFC TEFC
Tab. 14 Compressor motor
Rated speed [rpm]:
Maximum working pres‐
sure [psig]
AIRTOWER 3C AIRTOWER 4C AIRTOWER 5C AIRTOWER
7.5C
125 3520 3520 3520 3540
160 3520 3520 3520 3540
217 — 3520 3520 3540
Tab. 15 Compressor drive motor rated speed
2 Technical Data
2.11 Cooling oil charge
9_6917 34 USE
Operator Manual Screw Compressor
AIRTOWER 3C–7.5C Tri-Voltage 9

2.13 Sound emission
AIRTOWER 3C AIRTOWER 4C AIRTOWER 5C AIRTOWER
7.5C
Sound pressure lev‐
el [dB(A)]
69 70 70 70
Sound pressure level as per ISO 2151 and the basic standard ISO 9614-2, tolerance: ±3 dB(A) at
maximum machine working pressure
Tab. 16 Sound emission
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 2014 , 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 configura‐
tion output as shown in Figure 2 and Figure 3. In a symmetrical three phase supply the phase an‐
gles and voltages are all the same.
Other power supplies are not suitable.
Fig. 2 Three-phase star (wye); 4 wire; grounded neutral
Fig. 3 Three-phase star (wye); 3 wire; grounded neutral
Further information Please contact an authorized KAESER service representative for options.
The electrical diagram 13.3 contains further specifications for electrical connection.
2 Technical Data
2.13 Sound emission
10
Operator Manual Screw Compressor
AIRTOWER 3C–7.5C Tri-Voltage 9_6917 34 USE