Copeland Screw Compressors Semi-Hermetic Compact ...

Copeland ScrewCopeland ScrewCopeland ScrewCopeland ScrewCopeland Screw ™ CompressorsCompressorsCompressorsCompressorsCompressorsSemi-Hermetic Compact Semi-Hermetic Compact Semi-Hermetic Compact Semi-Hermetic Compact Semi-Hermetic Compact Application ManualApplication ManualApplication ManualApplication ManualApplication Manual

1 General1 General1 General1 General1 General

2 Design and functions2 Design and functions2 Design and functions2 Design and functions2 Design and functions2.1 Design features2.2 Compression process Vi control2.3 Capacity control and start unloading2.4 Hydraulic control2.5 Starting the compressor2.6 Infinite capacity control

Oil circulation

3 Lubricants3 Lubricants3 Lubricants3 Lubricants3 Lubricants

4 Integration into the refrigeration circuit4 Integration into the refrigeration circuit4 Integration into the refrigeration circuit4 Integration into the refrigeration circuit4 Integration into the refrigeration circuit1.1 Mounting the compressor1.2 System layout1.3 Guide lines for special system

variations1.4 Additional cooling by liquid injection1.5 Additional cooling by external oil

cooler

5 Economizer operation5 Economizer operation5 Economizer operation5 Economizer operation5 Economizer operation5.1 General5.2 Operation principal5.3 ECO operation with subcooling circuit5.4 ECO operation with intermediate

pressure receiver5.5 Layout and selection

recommendations5.6 Additional components5.7 Control

6 Electrical connections6 Electrical connections6 Electrical connections6 Electrical connections6 Electrical connections6.1 Motor design6.2 Selection of electrical components6.3 Compressor protection system6.4 Schematic wiring diagrams

AE4-1322 April 2002

SCH2 & SCA2SCH2 & SCA2SCH2 & SCA2SCH2 & SCA2SCH2 & SCA2High Temp Compressors

35 – 140 Horsepower

Contents

© 2002 Copeland CorporationIssued 4-2002Printed in U.S.A.

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AE4-1322

© 2002 Copeland CorporationIssued 4-2002Printed in U.S.A. 2

11111.GeneralGeneralGeneralGeneralGeneral

This new series represents the result of further develop-ment to provide a simplified and favorably priced screwcompressor for use in factory made systems.

Contrary to the semi-hermetic and open type, SHM/SHL and SDM/SDL compressor models for commercialand industrial installation, the compact screws aredesigned with an integral oil separator. The effortinvolved in installation is therefore comparable with thatfor semi-hermetic reciprocating compressors.

In addition to this, the electrical control and the monitor-ing of the oil circuit has been simplified. The provenbasic construction and the ease of service have beenretained.

The most modern screw compressor technology is nowavailable in the middle capacity range for compact liquidchillers and air conditioning equipment.

2. Design and function2. Design and function2. Design and function2. Design and function2. Design and function

2.1 Design features

Copeland Compact screws are of the twin rotor designwith a newly-developed profile geometry (lobe ratio 5:6).The main parts of these compressors are the two rotors(male and female rotor), which are fitted into a closedhousing. The rotors are precisely located at both endsin rolling contact bearings (radial and axial), which, inconjunction with the generously sized oil supplychambers, provides optimum emergency runningcharacteristics.

Owing to the specific design, this type of compressordoes not require any working valves. To protect againstreverse running when the compressor is switched off(expansion operation) a check valve is incorporated inthe discharge chamber (this valve does not, however,replace any check valves required by the systemdesign). An internal pressure relief valve is utilized forover-pressure protection.

The compressor is driven by a three-phase asynchro-nous motor, which is built into the compressor housing.The motor rotor is located on the shaft of the malescrew rotor. Cooling is achieved by cold refrigerant

vapor, which mainly flows through bores in the motorrotor.

The main technical features:

Balanced product rangeBalanced product rangeBalanced product rangeBalanced product rangeBalanced product range• • • • • 8 basic models• • • • • Tight performance graduation

Minimal space requirements and convenientMinimal space requirements and convenientMinimal space requirements and convenientMinimal space requirements and convenientMinimal space requirements and convenientpiping designpiping designpiping designpiping designpiping design• Shortest installed length in its performance category

- shut-off valves / connections within compressordimensions

• Suction and discharge gas connections can berotated in 90° increments

• Terminal box accessible from top, wire access fromunderneath

Universal applicationsUniversal applicationsUniversal applicationsUniversal applicationsUniversal applications••••• R134a, R407C and R22••••• R404A, R507A upon request••••• With or without economizer••••• Optimized R-134a version (SCA2)

New high-efficiency profileNew high-efficiency profileNew high-efficiency profileNew high-efficiency profileNew high-efficiency profile• Further developed geometry• High rigidity• Patented manufacturing process for highest

precision• High tip speed to minimize blow-by

Double-walled, pressure-compensated rotorDouble-walled, pressure-compensated rotorDouble-walled, pressure-compensated rotorDouble-walled, pressure-compensated rotorDouble-walled, pressure-compensated rotorhousinghousinghousinghousinghousing••••• Extremely stable, therefore no expansion even at

high pressure levels••••• Additional sound attenuation

Proven, long-life bearings with pressure unloadingProven, long-life bearings with pressure unloadingProven, long-life bearings with pressure unloadingProven, long-life bearings with pressure unloadingProven, long-life bearings with pressure unloading• Robust axial bearings in tandem configuration• Bearing chamber pressure isolated by seal rings• Pressure unloading of axial bearings

Optimized oil managementOptimized oil managementOptimized oil managementOptimized oil managementOptimized oil management• Three-stage oil separator• Long-life oil filter 10 µ mesh size• Pressure relieved bearing chamber ensuring mini-

mum refrigerant dilution in the oil and thus higherviscosity

Large volume motor for part winding or direct startLarge volume motor for part winding or direct startLarge volume motor for part winding or direct startLarge volume motor for part winding or direct startLarge volume motor for part winding or direct start- optional star delta design- optional star delta design- optional star delta design- optional star delta design- optional star delta design• Especially high efficiency

Semi-hermetic compact screwsSemi-hermetic compact screwsSemi-hermetic compact screwsSemi-hermetic compact screwsSemi-hermetic compact screwsSCH2/SCA2 seriesSCH2/SCA2 seriesSCH2/SCA2 seriesSCH2/SCA2 seriesSCH2/SCA2 series35 to 140 HP Nominal motor power35 to 140 HP Nominal motor power35 to 140 HP Nominal motor power35 to 140 HP Nominal motor power35 to 140 HP Nominal motor power

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• Integrated PTC sensors in each winding coil• Slot keys for maximum operating safety• Stator is slide fit (field replaceable)

Intelligent electronicsIntelligent electronicsIntelligent electronicsIntelligent electronicsIntelligent electronics• Thermal motor temperature control by winding PTCs• Phase sequence control for direction of rotation• Manual reset lock-out• Oil temperature protection by PTC sensor

Flexible with additional coolingFlexible with additional coolingFlexible with additional coolingFlexible with additional coolingFlexible with additional cooling• Direct liquid injection• External oil cooler for extended application and

highest efficiency

Dual capacity controlDual capacity controlDual capacity controlDual capacity controlDual capacity control• Infinite or 4-step slide control with Vi compensation.

Alternative operation modes by varying the controlsequence only - no need for compressor modification

• Simple control by solenoid coils• Automatic start unloading

Economizer with sliding suction positionEconomizer with sliding suction positionEconomizer with sliding suction positionEconomizer with sliding suction positionEconomizer with sliding suction position• Unique for compact screws• Efficient economizer operation with part load as well• Highest cooling capacity and energy efficiency at full

and part load conditions

Fully equippedFully equippedFully equippedFully equippedFully equipped• Capacity control / start unloading• Suction and Discharge shut-off valve• Check valve in discharge gas outlet• Oil sight glass• Insertion type oil heater with sleeve• Oil fill / drain service valve• Suction gas filter with large surface are and fine mesh• Electronic protection system

Proven optional accessoriesProven optional accessoriesProven optional accessoriesProven optional accessoriesProven optional accessories• Oil level switch• Shut-off valve / adapter for economizer operation and

liquid injection• Adapter for external oil cooler

2.2 Compression process V2.2 Compression process V2.2 Compression process V2.2 Compression process V2.2 Compression process Viiiii-control-control-control-control-control

With screw compressors, suction, compression anddischarge occur in one flow direction. With this processthe suction gas is pressed into the profile hollows by theprofile peaks. The volume is steadily reduced and it isthereby compressed. The compressed gas is thendischarged through a discharge port whose size andgeometry determine the so called “internal volume ratio

(Vi)”. This value must have a defined relationship to themass flow and the working pressure ratio, to avoidlosses in efficiency due to over- and under-compres-sion.

The internal discharge ports of the SCH2/SCA2 screwcompressors are designed for a very wide applicationrange.

In view of high efficiency and operational safety a part ofthe discharge channel is integrated into the controlslide, which enables a Vi control at part load conditions.Due to this the internal volume ratio (Vi) virtually re-mains constant down to approximately 70% part load.

The economizer channel built into the control slide isanother outstanding feature (figure 3). It enables a fullyfunctional operation of the subcooler circuit indepen-dently from the compressor’s load conditions. This is adesign solution which is unique for screw compressorsof this size. This ensures highest possible capacity andefficiency at both full and part load conditions. Fordetails regarding economizer operation see Section 5.

2.3 Capacity control and start unloading2.3 Capacity control and start unloading2.3 Capacity control and start unloading2.3 Capacity control and start unloading2.3 Capacity control and start unloading

SCH2/SCA2 models are provided as a standard with a“Dual Capacity Control” (slide system). This allows forinfinite infinite infinite infinite infinite or 4-step capacity control4-step capacity control4-step capacity control4-step capacity control4-step capacity control without compressormodifications. The different operating modes can beachieved by changing the control sequences of thesolenoid valves.

The special geometry of the slide means that thevolume ratio Vi is adjusted to the operating conditions inpart-load operation. This provides particularly highefficiency.

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Another feature of this system is the automatic start-unloading. It reduces starting torque and accelerationtimes considerably. This not only puts lower stresseson motor and mechanical parts but also reduces theload on the power supply network.

Significant design features are the robust dimensioningas well as the precise guidance of the slide elementsand the control piston. Capacity control is achieved bymeans of solenoid valves that are flanged on to thecompressor. A “dual set point controller” or any similarcomponent is suitable as a control module.

2.4 Hydraulic control2.4 Hydraulic control2.4 Hydraulic control2.4 Hydraulic control2.4 Hydraulic control

Figure 3 shows the design principle of the hydraulicscheme. By moving the slide the suction gas flow iscontrolled.

If the slide is moved totally to the suction slide (in thefigure 3 to the left), the working space between theprofiles is filled with suction gas. The more the slide ismoved to the discharge slide, the smaller the resultingprofile volume becomes. Less refrigerant is taken in.The mass flow is lower, and the cooling capacitydecreases.

The slide is controlled by a hydraulic piston. If the valveCR4 is opened, the oil pressure in the pressure

chamber increases. The slide is moved to the suctionside. The cooling capacity increases.

If the valve CR1, CR2 or CR3 is opened, the pressureon the hydraulic piston decreases. By means of thedischarge gas the slide is pressed to the dischargeside. The cooling capacity is reduced.

2.5 Starting the compressor2.5 Starting the compressor2.5 Starting the compressor2.5 Starting the compressor2.5 Starting the compressor

During the shut - down of the compressor the solenoidvalve CR3 is open. The pressure in the hydrauliccylinder is then released. The spring (fig. 3) pushes theslide to the discharge side end position.

When starting the compressor, it is unloaded. ValveCR4 is energized on demand thus moving the slidetowards the suction side. The refrigerating capacityincreases to the set load condition by energizing thevalves CR1, CR2 or CR3.

2.6 Infinite capacity control2.6 Infinite capacity control2.6 Infinite capacity control2.6 Infinite capacity control2.6 Infinite capacity control

Infinite capacity control is recommended for systemswhere high control accuracy is required. For controlprinciple see charts A, B, and C.

If the actual value is within the set control range H, thecooling demand of the plant remains unchanged. Then

Figure 3Oil Hydraulic Scheme

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there is no need to move the slide. No solenoid valveis energized.

The control input can be the air or water temperature atthe evaporator or the suction pressure.

Chart AControl Sequence – Infinite Capacity ControlControl Sequence – Infinite Capacity ControlControl Sequence – Infinite Capacity ControlControl Sequence – Infinite Capacity ControlControl Sequence – Infinite Capacity Control

Minimum CapacityMinimum CapacityMinimum CapacityMinimum CapacityMinimum Capacity mmmmm

CR 1 2 3 4Start/Stop m m l m

Cap ⇑⇑⇑⇑⇑ m m m l

Cap ⇓⇓⇓⇓⇓ m m l m

Cap ⇔⇔⇔⇔⇔ m m m m

Cap. 100% m m m l

Cap. Min.W m m l m

Chart BControl Sequence – Infinite Capacity ControlControl Sequence – Infinite Capacity ControlControl Sequence – Infinite Capacity ControlControl Sequence – Infinite Capacity ControlControl Sequence – Infinite Capacity Control

Minimum Capacity 50%Minimum Capacity 50%Minimum Capacity 50%Minimum Capacity 50%Minimum Capacity 50%

Cap ⇑⇑⇑⇑⇑ mmmmm mmmmm lllll

4 Cap. mmmmm lllll mmmmm mmmmm

Min.50%

Increased cooling demandIncreased cooling demandIncreased cooling demandIncreased cooling demandIncreased cooling demand

If the actual value exceeds the upper set point, thecooling demand has increased (operating point A in fig.4). The solenoid valve CR4 is opened for short intervalstill the actual value is within the set control range again(operating point B). Now the compressor operates withincreased cooling capacity.

Chart CControl Sequence – 4-Step Capacity ControlControl Sequence – 4-Step Capacity ControlControl Sequence – 4-Step Capacity ControlControl Sequence – 4-Step Capacity ControlControl Sequence – 4-Step Capacity Control

CR 1 2 3 4Start/Stop m m l m

Cap 25% m m l y

Cap 50% m l m y

Cap 75% l m m y

Cap. 100% m m m m

m Solenoid Coil De-Energized Solenoid Coil De-Energized Solenoid Coil De-Energized Solenoid Coil De-Energized Solenoid Coil De-Energizedl Solenoid Coil EnergizedSolenoid Coil EnergizedSolenoid Coil EnergizedSolenoid Coil EnergizedSolenoid Coil Energizedy Solenoid Coil Pulsing (10 secs. on / 10 secs. off) Solenoid Coil Pulsing (10 secs. on / 10 secs. off) Solenoid Coil Pulsing (10 secs. on / 10 secs. off) Solenoid Coil Pulsing (10 secs. on / 10 secs. off) Solenoid Coil Pulsing (10 secs. on / 10 secs. off)

Decreased cooling demandDecreased cooling demandDecreased cooling demandDecreased cooling demandDecreased cooling demand

A decreased cooling demand falls below the lower setpoint (operating point C). The solenoid valve CR3 nowopens for short intervals till the actual value is withinthe set control range again (operating point D). Thecompressor operates with decreased cooling capacity.

With the solenoid valves CR3 / CR4, capacity can becontrolled between 100% and nominally 25%. Alterna-tively valves CR2 / CR4 can be energized; in this casecontrol will be limited between 100% and nominally50%.

The limitation to a minimum of approximately 50%cooling capacity is recommended for the followingapplication conditions (control with valves CR2 / CR4):

• In case of operation at high-compression ratios /condensing temperatures, the main concern is highdischarge temperature.

• For systems with multiple compressors either usedin split or singlecircuits. Under these conditionscapacity control between 100 and 50%, in combina-tion with individual compressor on/off cycling,guarantees highest possible efficiency – withoutsignificant restrictions in the application range. Dueto the usually lowered condensing temperature atpart load conditions, the lead compressor can evenbe operated very effectively down to nominal 25% ofcooling capacity (with valves CR3 / CR4)

2.7 4-step capacity control2.7 4-step capacity control2.7 4-step capacity control2.7 4-step capacity control2.7 4-step capacity control

This type of capacity control is particularly suited tosystems with high inertia – in connection with indirectcooling, for example. Liquid chillers are typical applica-tions. Chart C shows the control of the solenoid valvesor the individual capacity steps.

The cycle time of the intermitting valve, CR4, should beadjusted to about 10 seconds before commissioning.Even shorter intervals may be necessary, particularlywith systems with high pressure differences. Therefore,in this case adjustable time relays should be used.For this type of operation a restriction of minimumrefrigeration capacity to approximately 50% is alsorecommended, as with the systems described inSection 2.6. Control is then effected with the CR4 valve(intermittent) and with CR1 (75%) and CR2 (50%).

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2.8 Oil circulation2.8 Oil circulation2.8 Oil circulation2.8 Oil circulation2.8 Oil circulation

The lubrication circuit is designed as is typical forscrew compressors. This type of design, however, hasa vessel directly flanged-on to the compressor housingat the high-pressure side. It contains the oil reservoir.The vessel simultaneously serves as an oil separator.

The oil circulation results from the pressure differenceto the oil injection point, where the pressure level isslightly above suction pressure. The oil flows through agenerously sized filter element to the throttle point andsubsequently to the bearing chambers and the profilespaces of the rotors. The oil is then transportedtogether with the refrigerant vapor in the direction ofcompression. In addition to lubrication it also providesa dynamic seal between the rotors and between thehousing and the rotors. The oil then flows together withthe compressed vapor into the reservoir vessel. Here oiland vapor are separated in a highly efficient process.The oil collects in the lower part of the separator vessel

and flows back into the compressor either direct or viaan external oil cooler. Depending on the operatingconditions the circulating oil must be cooled with liquidinjection or an external oil cooler (see Section 4.4 and4.5)

Monitor the oil circuitMonitor the oil circuitMonitor the oil circuitMonitor the oil circuitMonitor the oil circuit

• For short circuits without without without without without refrigerant injection foradditional cooling and for small system volumesand refrigerant charges: indirect monitoring bymeans of oil temperature protection (standard)

CAUTION!CAUTION!CAUTION!CAUTION!CAUTION!Lack of oil leads to a dramaticLack of oil leads to a dramaticLack of oil leads to a dramaticLack of oil leads to a dramaticLack of oil leads to a dramatic

temperature increase.temperature increase.temperature increase.temperature increase.temperature increase.

Figure 4Infinite capcity control scheme

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• For circuits withwithwithwithwith refrigerant injection for additionalcooling and / or for greater system volumes:Direct monitoring by means of an oil level monitor inthe oil separator(optional accessory) is recom-mended.

3 Lubricants3 Lubricants3 Lubricants3 Lubricants3 Lubricants

Apart from the lubrication it is also the task of the oil toprovide dynamic sealing of the rotors. Special demandsresult from this with regard to viscosity, solubility andfoaming characteristics. Copeland approved oils maytherefore be used only.

Important instructionsImportant instructionsImportant instructionsImportant instructionsImportant instructions

• Observe the application limits of the compressors.

• The lower limit value of the discharge gas tempera-ture (140°F) is a reference value only. It must beensured by sufficient suction super-heat that thedischarge gas temperature is at least 54°F (R134a,R404A / R507A mi. 36°F) above the condensingtemperature.

• Ester oils Solest170 (for HFC refrigerants) andCP4214-320 (for R22) are very hygroscopic. Specialcare is therefore required when dehydrating thesystem and when handling open oil containers.

• A corrected design may be necessary for direct-expansion evaporators with finned tubes on therefrigerant side (consultation with manufacturer).

The above information corresponds to the presentstatus of our knowledge and is intended as a guide forgeneral applications. This information does not havethe purpose of confirming certain oil characteristics ortheir suitability for a particular case.

4 Integration into the refrigeration circuit4 Integration into the refrigeration circuit4 Integration into the refrigeration circuit4 Integration into the refrigeration circuit4 Integration into the refrigeration circuit

Compact screw compressors are well suited forintegration in factory-assembled plants (liquid chillersand air conditioning units). Their use in extendedsystems is also possible, for example, with remotelyinstalled condenser.

Systems with multiple compressors should preferablybe designed with individual circuits. Parallel compoundis possible, but requires a special oil equalizingsystem by means of oil level control.

4.1 Mounting the compresso4.1 Mounting the compresso4.1 Mounting the compresso4.1 Mounting the compresso4.1 Mounting the compressor

With stationary systems the compressor has to beinstalled horizontally.

In case of marine application, mounting in direction ofthe longitudinal axis of the boat may be required.Detailed layout recommendation can be provided uponrequest.

Anti-vibration mountingsAnti-vibration mountingsAnti-vibration mountingsAnti-vibration mountingsAnti-vibration mountings

Rigid mounting of the compressor is possible. The useof anti-vibration mountings especially matched to thecompressors is recommended, however, to reduce thetransmission of body radiated noise.

With direct mounting on water cooled condensers:

CAUTION!CAUTION!CAUTION!CAUTION!CAUTION!Do not mount the compressor directlyDo not mount the compressor directlyDo not mount the compressor directlyDo not mount the compressor directlyDo not mount the compressor directly

on the condenseron the condenseron the condenseron the condenseron the condenser. Do not use the. Do not use the. Do not use the. Do not use the. Do not use the condenser structural mmember! condenser structural mmember! condenser structural mmember! condenser structural mmember! condenser structural mmember!

Damage of the condenser is possibleDamage of the condenser is possibleDamage of the condenser is possibleDamage of the condenser is possibleDamage of the condenser is possible (fatigue fractures). Use anti-vibration (fatigue fractures). Use anti-vibration (fatigue fractures). Use anti-vibration (fatigue fractures). Use anti-vibration (fatigue fractures). Use anti-vibration

mountings!mountings!mountings!mountings!mountings!

The installation of the anti-vibration mountings is shownin figure 5. The bolts should only be tightened untilslight deformation of the upper rubber disc is justvisible.

Figure 5Mounting and installation

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Figure 6Typical system design

4.2 System layout4.2 System layout4.2 System layout4.2 System layout4.2 System layout

The compressor is installed in the refrigerating circuitsimilar to semi-hermetic reciprocating compressors.

Plant design and pipe layoutPlant design and pipe layoutPlant design and pipe layoutPlant design and pipe layoutPlant design and pipe layout

The pipelines and the system layout must be arrangedso that the compressor cannot be flooded with oil orliquid refrigerant during shutdown.

Suitable measures are (also as a simple protectionagainst liquid slugging during start)• either to raise the suction line after the evaporator

(goose neck)• or to install the compressor above the evaporator.

Additional safety is provided by a solenoid valveinstalled directly before the expansion valve. In additionthe discharge line should first be angled downwardsafter the shut-off valve.

Due to the low level of vibration and discharge gaspulsation the suction and discharge lines can be madewithout the use of flexible elements or mufflers.However, pipelines must be sufficiently flexible andsupported to not exert any strain on the compressor.The most favorable pipe runs are designed parallel tothe compressor axis and the discharge line firstleading downwards. The distance to the axis should beas short as possible and the parallel pipe sectionshould be at least half the compressor’s length.Finally, long radius elbows should be used.

Due to gas pulsations there can be vibrations espe-cially in discharge and economizer lines. Thereforecritical pipe lengths (+/- 15%) with their natural fre-quencies being in resonance with the compressorpulsations must be avoided.

Among other things the operating conditions and therefrigerant (sonic speed) as well as the compressor’spulsation frequency must be considered in the calcula-tion.

The base frequency of the compressor is approx.250Hz (50Hz network) or 300 Hz (60 Hz network).Frequencies of higher orders (500 / 1000 Hz or 600 /1200 Hz) should also reviewed at in the final layout.

Oil heaterOil heaterOil heaterOil heaterOil heater

An oil heater is provided to prevent too high a concen-tration of refrigerant in the oil during shutdown. It ismounted in a heater sleeve and can be replaced ifnecessary without accessing the refrigerating circuit.For electrical connection see section 6.4.

Additional insulation of the oil separatorAdditional insulation of the oil separatorAdditional insulation of the oil separatorAdditional insulation of the oil separatorAdditional insulation of the oil separator

Operation at low ambient temperatures or at hightemperatures on the discharge side during standstill(such as heat pumps) requires additional insulation ofthe oil separator.

Filter drierFilter drierFilter drierFilter drierFilter drier

Generously sized filter driers of suitable quality shouldbe used to ensure a high degree of dehydration and tomaintain the chemical stability of the system.

Suction side cleaning filterSuction side cleaning filterSuction side cleaning filterSuction side cleaning filterSuction side cleaning filter

The use of a suction side filter (filter mesh 25 m) willprotect the compressor from damage due to dirt fromthe system and is strongly recommended for site builtsystems.

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Expansion valve and evaporatorExpansion valve and evaporatorExpansion valve and evaporatorExpansion valve and evaporatorExpansion valve and evaporator

Expansion valve and evaporator have to be adjustedusing utmost care. This is especially important forthose systems that cover a large control range, e.g.100% to 25%. In each case, sufficient suction gassuperheat and stable operating conditions must beassured in full load as well as part load modes.Depending on the evaporator’s design and performancerange several circuits may be necessary each withseparate expansion and solenoid valves.

3.3 Guidelines for special system variations3.3 Guidelines for special system variations3.3 Guidelines for special system variations3.3 Guidelines for special system variations3.3 Guidelines for special system variations

Pump down circuitPump down circuitPump down circuitPump down circuitPump down circuit

If the evaporator and / or the suction line can becomewarmer than the compressor during shutdown, a “pumpdown” cycle must be incorporated in addition to the oilheater.

Additional check valve in the discharge line andAdditional check valve in the discharge line andAdditional check valve in the discharge line andAdditional check valve in the discharge line andAdditional check valve in the discharge line andautomatic sequence controlautomatic sequence controlautomatic sequence controlautomatic sequence controlautomatic sequence control

For systems with multi-circuit condensers and / orevaporators, an increased danger exists when indi-vidual circuits are shut off. During this period liquidrefrigerant can migrate into the evaporator (no tempera-ture and pressure equalization possible). In thesecases an additional check valve must be installed inthe discharge line. In addition the compressors shouldbe operated with an automatic sequence control.

The same is also valid for individual systems withouttemperature and pressure equalization during longershutdown. In extreme cases a suction accumulator or“pump down” cycle can also become necessary.

Additional oil level controlAdditional oil level controlAdditional oil level controlAdditional oil level controlAdditional oil level control

The above guidelines also apply to systems with longpipelines (suchas a remote evaporator and / or con-denser). In addition the compressor must be equippedwith an oil level switch (accessory). For electricalconnection see Section 6.4.

Systems with reverse cycling and hot gas defrostSystems with reverse cycling and hot gas defrostSystems with reverse cycling and hot gas defrostSystems with reverse cycling and hot gas defrostSystems with reverse cycling and hot gas defrost

These system layouts require individually systemdesign review to protect the compressor against liquidslugging and increased oil carry-over. A suction

accumulator is recommended to protect against liquidslugging. To effectively avoid increased oil carry-over(such as due to a rapid decrease of pressure in the oilseparator), the oil temperature must remain at least54° F above the condensing temperature during chargeover. In addition, it may be necessary to install apressure regulator immediately after the oil separatorto limit pressure drop. Under certain conditions it isalso possible to turn off the compressor shortly beforethe change over procedure and to restart after pressureequalization. It must however be assured that thecompressor is operating with the required minimumpressure differential no longer than 30 seconds (seeapplication ranges Section 9).

3.4 Additional cooling by means of direct liquid3.4 Additional cooling by means of direct liquid3.4 Additional cooling by means of direct liquid3.4 Additional cooling by means of direct liquid3.4 Additional cooling by means of direct liquidinjectioninjectioninjectioninjectioninjection

Additional cooling is required in areas of high condens-ing and / or low evaporating temperatures. A relativelysimple method is direct liquid inject at the economizerconnection.

The following criteria must be followed to ensurereliable operation and to avoid excessive dilution of theoil.

Liquid inject valveLiquid inject valveLiquid inject valveLiquid inject valveLiquid inject valve

Specially designed expansion valves are only suitablefor liquid injection. They must control the dischargetemperature to setting of 190°F (e.g. Danfoss TEAT20,also series 935-101-B, Sporian Y1037).

The valve bulb must be mounted on the discharge line:

• Clean the tubes surface carefully to bright metal.Distance from discharge shut-off valve approx. 8 to10 inches.

• Apply heat transfer paste to the contact surface.

• Fix the bulb firmly with adequate pipe clips. Mindheat expansion!

• Insulate the bulb and the section of discharge line

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Pipe runsPipe runsPipe runsPipe runsPipe runs

To ensure a bubble free liquid supply to the liquidinjection valve, the connection must be made on thebottom of a horizontal section of the liquid line.

Installation of the liquid inject valve at the com-Installation of the liquid inject valve at the com-Installation of the liquid inject valve at the com-Installation of the liquid inject valve at the com-Installation of the liquid inject valve at the com-pressorpressorpressorpressorpressor

• Min. 6 to 8 in. above liquid injection connection

CAUTION!CAUTION!CAUTION!CAUTION!CAUTION!VVVVVibration fractures possible! install liquidibration fractures possible! install liquidibration fractures possible! install liquidibration fractures possible! install liquidibration fractures possible! install liquid

injection and solenoid valves withinjection and solenoid valves withinjection and solenoid valves withinjection and solenoid valves withinjection and solenoid valves withadequate supports!adequate supports!adequate supports!adequate supports!adequate supports!

Check for vibration during operation!Check for vibration during operation!Check for vibration during operation!Check for vibration during operation!Check for vibration during operation!

Calculating the cooling capacity of the liquidCalculating the cooling capacity of the liquidCalculating the cooling capacity of the liquidCalculating the cooling capacity of the liquidCalculating the cooling capacity of the liquidinjection valveinjection valveinjection valveinjection valveinjection valve

• With the selection software• Consider the most extreme conditions to be

expected during actual operation:- min. evaporating temperature- max. suction gas superheat and condensing

temperature

Further conditions for valve selectionFurther conditions for valve selectionFurther conditions for valve selectionFurther conditions for valve selectionFurther conditions for valve selection

• Pressure at the injection point:- R134a approximately 30 to 45 psig above

suction pressure R407C, R22 approx. 40 to50 psig above suction pressure

- Never size the valve too large danger ofrefrigerant flooding!

Additional components in the liquid lineAdditional components in the liquid lineAdditional components in the liquid lineAdditional components in the liquid lineAdditional components in the liquid line

• Solenoid valve (energized parallel to compressorcontactor)

• Filter dryer (if required)• Liquid sight glass

Figure 7Liquid injection valve (system design)

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3.5 Additional cooling by means of external oil3.5 Additional cooling by means of external oil3.5 Additional cooling by means of external oil3.5 Additional cooling by means of external oil3.5 Additional cooling by means of external oilcoolercoolercoolercoolercooler

The application of an external oil cooler (air, water orrefrigerant cooled) instead of refrigerant inject providesadditional extension of the application envelopes andeven better efficiency.

When calculating an oil cooler, worst case operatingconditions must be used:• Min. evaporating temperature• Max. suction gas superheat• Max. condensing temperature• Operation mode (capacity control, ECO)

Oil cooler capacity can be calculated by using theselection software.

Recommendations for external oil coolersRecommendations for external oil coolersRecommendations for external oil coolersRecommendations for external oil coolersRecommendations for external oil coolers

• Connections for external oil coolers are located onthe back side of the compressor below the dis-charge shut-off valve (oval or rectangular flange).The flange is replaced by a tube adaptor (option):

• Install oil cooler as close as possible to the com-pressor.

• Piping design must avoid gas pockets and anydrainage of oil into the compressor during shut-downs (installation of the oil cooler preferably atcompressor level or below).

• Due to the additional oil volume (cooler, piping) asolenoid valve may be necessary in the oil line.This is to avoid oil migration into the compressorduring shutdowns. The solenoid valve must beinstalled close to the compressor’s oil inlet connec-tion and its electric control should be parallel to thecontactor’s normally open contact. Recommendedadditional components:

- Sight glass to check oil flow,- Manual shut-off ball valves in both feed and

return lines for ease of service,- Oil filter (max. 25 µ mesh size)

With an additional oil volume (cooler and piping) of10% of the compressor’s standard oil charge andassured cleanliness of components and pipes theabove mentioned measures can be omitted.

• Oil coolers must be controlled by thermostats (seetable for temperature settings).

• For rapid heating of the oil circuit and minimizingthe pressure drop with cold oil an oil by-pass (oreven heating the cooler during shut down) isrequired under the following conditions:- the oil temperature in the cooler drops below

60°F during shut down,- the oil volume of cooler plus oil piping exceeds

the compressor’s oil charge,- The oil cooler is an integral part of the con-

denser coil

• The by-pass valve should have a temperatureresponsive modulating control function. The use of asolenoid valve for intermittent control would requirehighly sensitive control thermostat and a minimalswitching differential (effective temperature variation< 18°F).

• The oil side pressure drop during normal operationshould not exceed 7 psig.

Water cooled oil coolerWater cooled oil coolerWater cooled oil coolerWater cooled oil coolerWater cooled oil cooler

Temperature control by thermostatic water regulator(for set point see table, required sensor temperatureshould be equal to or greater than 250°F).

Figure 8External oil cooler connection

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Air cooled oil coolerAir cooled oil coolerAir cooled oil coolerAir cooled oil coolerAir cooled oil cooler

Temperature control by thermostatic switching on andoff or stepless speed control of the cooler fan (seetable for set point, required sensor temperature shouldbe equal to or greater than 250°F).

If the oil coolers is integrated into the condenser theby-pass valve controls the temperature (see table forset point; admissible operating and / or sensor tem-perature should be equal to or greater than 250°F).

Thermosyphon oil cooling (cooling by refrigerant)Thermosyphon oil cooling (cooling by refrigerant)Thermosyphon oil cooling (cooling by refrigerant)Thermosyphon oil cooling (cooling by refrigerant)Thermosyphon oil cooling (cooling by refrigerant)

Temperature control either by thermostatic regulationvalve for refrigerant feed or by-pass valve (see table forset point; admissible operating and sensor temperatureshould be equal to or greater than 250°F).

As an example figure 11 shows a layout with a primaryreceiver after the condenser. An alternative layout of thethermosyphon circuit as well as refrigerant circulationby means of a pump or an ejection is also possible(information upon request).

4 Economizer operation

1.1 General1.1 General1.1 General1.1 General1.1 General

SCH2/SCA2 screw compressors are designed foreconomizer operation “ECO”. With this operation modeboth cooling capacity and efficiency are improved bymeans of a sub-cooling circuit or 2-stage refrigerantexpansion. There are capacity and efficiency advan-tages in ECO operation over the conventional applica-tion, particularly at high condensing temperatures.

A unique feature of the compact screws is the econo-mizer channel integrated into the control slide (fig.12).This enables to operate the sub-cooling circuit regard-less of the compressor load condition. Screw com-pressors with a fixed ECO suction position have thisfrequently located in the suction area of the rotorsduring part load and then has no effect.

Figure 9Water-cooled oil cooler

Figure 11Thermosyphon oil cooling

Figure 10Air cooled oil coolers

DL SL

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5.2 Operation principle5.2 Operation principle5.2 Operation principle5.2 Operation principle5.2 Operation principle

With screw compressors the compression processoccurs only in one flow direction (see Section 2.2).This fact enables to locate an additional suction port atthe rotor housing. The position is selected so that thesuction process has already been completed and aslight pressure increase has taken place. Via thisconnection an additional mass flow can be taken in,which has only a minimal effect on the flow from thesuction side.

The pressure level at the ECO suction point is similarto the intermediate pressure with 2-stage compres-sors. This means that an additional sub-cooling circuitor intermediate pressure receiver for 2-stage expansioncan be integrated into the system. This designachieves a significantly higher cooling capacity throughadditional liquid sub-cooling. At the same time, there isa relatively low increase in the compressor’s powerinput, as the total working process becomes moreefficient – due to the higher suction pressure, amongother things.

5.3 Economizer operation with sub-cooling circuit5.3 Economizer operation with sub-cooling circuit5.3 Economizer operation with sub-cooling circuit5.3 Economizer operation with sub-cooling circuit5.3 Economizer operation with sub-cooling circuit

With this operation mode a heat exchanger is utilizedas a liquid sub-cooler. A part of the refrigerant massflow from the condenser enters the sub-cooler via anexpansion device, and evaporates upon absorbing heatfrom the counter-flowing liquid refrigerant (sub-cooling).The superheated vapor is taken in at the compressor’sECO connection, mixed with the mass flow from theevaporator and compressed to a high pressure.

With this type of operation the sub-cooled liquid isunder condensing pressure. Therefore the piping to theevaporator does not require any special features –apart from insulation.The system can be applieduniversally.

5.4 ECO operation with intermediate pressure5.4 ECO operation with intermediate pressure5.4 ECO operation with intermediate pressure5.4 ECO operation with intermediate pressure5.4 ECO operation with intermediate pressurereceiverreceiverreceiverreceiverreceiver

This layout version for 2-stage refrigerant pressure reliefis particularly advantageous in connection with floodedevaporators and is therefore primarily used in plantswith large cooling capacity.

Figure 12System with sub-cooling circuit

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5.5 Layout and selection recommendations5.5 Layout and selection recommendations5.5 Layout and selection recommendations5.5 Layout and selection recommendations5.5 Layout and selection recommendations

Pipe layoutPipe layoutPipe layoutPipe layoutPipe layout

• Design the sub-cooler so that during shutdown,neither liquid refrigerant nor oil can enter the com-pressor.

• Until operating conditions are established duringtemporary operation without economizer and whenswitching off the compressor, the compressor candischarge a certain amount of oil through the ECOconnection. Oil transfer into the sub-cooler musttherefore be prevented by a pipe bending verticallyupwards with a check valve (see fig.13).

In order to avoid instability of the check valve whenthe ECO circuit is switched off, a by-pass-line with asolenoid valve towards the suction side must also beincluded (1/4”). The solenoid valve is only open whenthe ECO is not operating. This way it createssufficient closing pressure for the check valve.

• See Section 6 for electric control. Other layoutversions are also possible, but must be checked fortheir suitability and operating safety in individualtests.

• The ECO connection leads directly into the profilearea. For this reason a high degree of cleanlinessmust be maintained for sub-cooler and pipes.

• Dimension of the ECO suction line:In view of the usually short pipe lengths, the followingpipe diameters can be used:SCH2 5000 to 9000 1 ¼” – 12 RotolockSCA2 3500 to 7000SCH2 11H0 to 14H0 1 ½” – 12 RotolockSCA2 9000 to 11H0

• Pipe vibrations:Due to the pulsations emitting from the profile areaof the compressor, critical pipe lengths must beavoided. See also Section 4.2.

5.6 Additional components5.6 Additional components5.6 Additional components5.6 Additional components5.6 Additional components

Refrigerant sub-coolerRefrigerant sub-coolerRefrigerant sub-coolerRefrigerant sub-coolerRefrigerant sub-cooler

Frost proof shell and tube, coaxial or plate heatexchangers are suitable as sub-coolers. In the designphase the relatively high temperature gradient on theliquid side must be taken into consideration.

For capacity determination see output date in thecompressor software:• Sub-cooler capacity• ECO mass flow• Saturated ECO temperature and• Liquid temperature.

Layout parametersLayout parametersLayout parametersLayout parametersLayout parameters

• Intermediate temperature- corresponds to the evaporating temperature in

the sub-cooler- for layout design, take 18°F suction gas

superheat into consideration

• Liquid temperature (inlet)As a nominal selection basis, liquid sub-cooling of4°F is assumed

example:tc = 90°F liquid temperature (inlet) = 86ºF.

• Liquid temperature (outlet) The software pre-setdate are based on 18°F above saturated ECOtemperature

Example:tm = +68ºF liquid temperature (outlet) = 86ºF

Input of individual data is possible. Keep in mind,however, that in practice a stable operating mode isvery difficult to achieve with differences betweenliquid temperature (outlet) and saturated ECOtemperature of less than 18°F.

Figure 13Liquid injection connections

Min 6 – 8” rise

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Thermostatic expansion valvesThermostatic expansion valvesThermostatic expansion valvesThermostatic expansion valvesThermostatic expansion valves

• Valve layout for liquid sub-cooler:- Basis is the sub-cooling capacity- Evaporating temperature corresponds to the

ECO intermediate temperature.- Valves with a superheat adjustment of about 10

K should be used in order to avoid unstableoperation when switching on the sub-coolingcircuit and in connection with load fluctuations.

- If the sub-cooling circuit is also operated underpart-load conditions, this must be given dueconsideration when designing the valves.

• Valve layout for evaporator:Due to the high degree of liquid sub-cooling suctionmass flow is much lower than with systems withsimilar capacity and no sub-cooler (see softwaredata). This requires a modified layout. In thiscontext the lower vapor content after expansionmust also be taken into consideration. For furtherhints on the layout of expansion valves and evapora-tors see Section 4.2.

5.7 Control5.7 Control5.7 Control5.7 Control5.7 Control

Between that start and the stabilization of operatingconditions, the solenoid valve of the sub-cooling circuitis switched on time delayed or depending on suctionpressure. For further hints and a schematic layoutdiagram see Section 6.4.

6 Electrical connection6 Electrical connection6 Electrical connection6 Electrical connection6 Electrical connection

6.1 Motor design6.1 Motor design6.1 Motor design6.1 Motor design6.1 Motor design

The compressors are supplied as standard with partwinding motors of connection (Part Winding “PW”).Start delta motors are available as special design.

Part winding motorsPart winding motorsPart winding motorsPart winding motorsPart winding motors

Starting methods (connections according to figures 14and 15):• Part winding start to reduce the starting current• Direct on line start (DOL)

Start delta motorsStart delta motorsStart delta motorsStart delta motorsStart delta motors

Starting methods (connections according to figures 16and 17).

The start current value in star mode (1/3 ofThe start current value in star mode (1/3 ofThe start current value in star mode (1/3 ofThe start current value in star mode (1/3 ofThe start current value in star mode (1/3 ofthe direct on line value) is generally statedthe direct on line value) is generally statedthe direct on line value) is generally statedthe direct on line value) is generally statedthe direct on line value) is generally statedaccording to standard locked rotor condi-according to standard locked rotor condi-according to standard locked rotor condi-according to standard locked rotor condi-according to standard locked rotor condi-tions. In realitytions. In realitytions. In realitytions. In realitytions. In reality, however, however, however, however, however, approx. 50% are, approx. 50% are, approx. 50% are, approx. 50% are, approx. 50% areobtained during the start. Moreoverobtained during the start. Moreoverobtained during the start. Moreoverobtained during the start. Moreoverobtained during the start. Moreover, when, when, when, when, whenswitching from start to delta mode there is aswitching from start to delta mode there is aswitching from start to delta mode there is aswitching from start to delta mode there is aswitching from start to delta mode there is acurrent peak as high as the direct start value.current peak as high as the direct start value.current peak as high as the direct start value.current peak as high as the direct start value.current peak as high as the direct start value.This is caused by the voltage interruptionThis is caused by the voltage interruptionThis is caused by the voltage interruptionThis is caused by the voltage interruptionThis is caused by the voltage interruptionduring switch-over of the contactors, whichduring switch-over of the contactors, whichduring switch-over of the contactors, whichduring switch-over of the contactors, whichduring switch-over of the contactors, whichresults in a speed drop due to theresults in a speed drop due to theresults in a speed drop due to theresults in a speed drop due to theresults in a speed drop due to thecompressorcompressorcompressorcompressorcompressor’’’’’s small rotating masses.s small rotating masses.s small rotating masses.s small rotating masses.s small rotating masses.

Figure 14

Figure 16

Figure 15

Figure 17

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6.2 Selection of electrical components6.2 Selection of electrical components6.2 Selection of electrical components6.2 Selection of electrical components6.2 Selection of electrical components

Cables, contractors and fusesCables, contractors and fusesCables, contractors and fusesCables, contractors and fusesCables, contractors and fuses

CAUTIONCAUTIONCAUTIONCAUTIONCAUTIONNominal power is not the same asNominal power is not the same asNominal power is not the same asNominal power is not the same asNominal power is not the same as

maximum motor power! When selectingmaximum motor power! When selectingmaximum motor power! When selectingmaximum motor power! When selectingmaximum motor power! When selectingcables, contactors and fuses: cables, contactors and fuses: cables, contactors and fuses: cables, contactors and fuses: cables, contactors and fuses: MaximumMaximumMaximumMaximumMaximum

operating current / maximum motoroperating current / maximum motoroperating current / maximum motoroperating current / maximum motoroperating current / maximum motor power must be considered. See chapter 8. power must be considered. See chapter 8. power must be considered. See chapter 8. power must be considered. See chapter 8. power must be considered. See chapter 8.

Contactor selection: according toContactor selection: according toContactor selection: according toContactor selection: according toContactor selection: according to operational category operational category operational category operational category operational category AC 3.AC 3.AC 3.AC 3.AC 3.

Part winding motorsPart winding motorsPart winding motorsPart winding motorsPart winding motors

The following current values appear in the part wind-ings:

PW1 PW250% 50%

Both of the contactors should be selected for at least60% of the maximum operating current.

Star delta motorsStar delta motorsStar delta motorsStar delta motorsStar delta motors

Calculate mains and delta contactor each to at least60%, start contactor to 33% of the maximum operatingcurrent.

Power factor correctionPower factor correctionPower factor correctionPower factor correctionPower factor correction

For the reduction of the reactive current when usinginductive loads (motors, transformers), power factorcorrection systems (capacitors) are increasingly beingused. However, apart from the undisputed powersupply advantages, experience shows that the layoutand execution of such systems is not a simple matter,as insulation damage on motors and increased contactarcing on contactors can occur.

With a view to a safe operating mode, the correctionsystem should be designed to effectively prevent “over-correction” in all operating conditions and the uncon-trolled discharge of the capacitors when starting andshutting down the motors.

General design criteriaGeneral design criteriaGeneral design criteriaGeneral design criteriaGeneral design criteria

• Maximum power factor (P.F. 0.95 - taking intoconsideration all load conditions.)

Individual correction (Fig. 21)Individual correction (Fig. 21)Individual correction (Fig. 21)Individual correction (Fig. 21)Individual correction (Fig. 21)

• With capacitors that are directly fitted to the motor(without the possibility of switching off withcontactors), the capacitor capacity must never begreater than 90% of the zero-load reactive capacityof the motor (less than 25% of max. motor power).With higher capacities there is the danger of self-exiting when shutting off, resulting in damage to themotor.

Figure 18Power factor correction on individual compressors

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• For part winding start a separate capacitor shouldbe used for each half of the winding (50% each).Only one capacitor is used for start delta motors(parallel to contactor K1).

• In the case of extreme load fluctuations (largecapacity range) combined with high demands on alow reactive capacity, capacitors that can beswitched on and off with contactors (in combinationwith a discharge throttle) may be necessary.Design is similar to central correction.

Central correction (Fig. 22)Central correction (Fig. 22)Central correction (Fig. 22)Central correction (Fig. 22)Central correction (Fig. 22)

• When the designing, connected loads and theoperating times of all inductive loads (includingfluorescent lamps if they do not have their owncorrection) must be taken into consideration.

• The number of capacitor stages must be selectedso that the smallest unit does not have a largercapacity than the lowest inductive load (with P.F.0.95). Extreme part load conditions are particularlycritical, such as can occur during the night, atweekends or while being put into operation. If loadsare too low the entire correction device should bedisconnected from the power supply.

• With central correction (as well as with individualcorrection with contactor control) discharge throttlemust always be provided. Reconnection to thepower supply may only occur after completedischarge and a subsequent time delay.

The layout of correction systems for motors withdirect starting is similar.

CAUTION!CAUTION!CAUTION!CAUTION!CAUTION!It is essential to observe the generalIt is essential to observe the generalIt is essential to observe the generalIt is essential to observe the generalIt is essential to observe the generaldesign and layout instruction of thedesign and layout instruction of thedesign and layout instruction of thedesign and layout instruction of thedesign and layout instruction of the correction system manufacturer correction system manufacturer correction system manufacturer correction system manufacturer correction system manufacturer.....

Frequency inverterFrequency inverterFrequency inverterFrequency inverterFrequency inverter

Operation with a frequency inverter is possible. How-ever, layout and operating conditions must be individu-ally approved by Copeland.....

3.3 Compressor protection system3.3 Compressor protection system3.3 Compressor protection system3.3 Compressor protection system3.3 Compressor protection system

The SCH2/SCA2 compressors are fitted with theprotection device INT69VSY-II.

Monitoring functionsMonitoring functionsMonitoring functionsMonitoring functionsMonitoring functions

• Winding temperature (PTC sensors in motorwinding)

- Interruption of the control current with excesstemperature

- Manual reset (after winding has cooled) byinterruption of supply voltage L/N for at least2 seconds

• Oil temperature (sensor with PTC resistance in oilsump)

- Function as above (winding temperature)

Figure 20Power factor correction on central power system

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• Direction of rotation/phase sequence (direct mea-surement at compressor terminals)- Immediate interruption of control current and

lock-out with wrong direction of rotation / phasesequence (indication via signal contact 12)

- Reset (after correction of fault) by interruption ofthe supply voltage L/N for at least 2 seconds.

The protection device is built into the terminal box.The wiring to the motor and oil temperature PTCsensors and also to be motor terminals is factorymounted. The electrical connections to the deviceshould be made according to figure 21 or 22 and theschematic wiring diagrams.

In principle the device could be also built into thecontrol panel. In the case it is essential to adhere tothe following recommendations:

Special attention must be given when fitting theINT69VSY-II in the control panel:

• The connecting cables to the motor terminals mustbe wired in the sequence described (L1 to terminal“1” etc.) Check with a direction of rotation indicator!

• Danger of induction!Only use shielded cables or a twisted pair toconnect to the PTC motor sensors and oil tempera-ture PTC sensors.

• Additional fuses (4 A) must be incorporated in theconnecting cables between “L1/L2/L3” of theprotection device and the motor terminals “1/2/3”.

• The terminals T1-T2 on the compressor and 1-2 onprotection device must not come into contact withsupply or control voltage.

CAUTIONCAUTIONCAUTIONCAUTIONCAUTIONIf the rotation direction is wrong: DangerIf the rotation direction is wrong: DangerIf the rotation direction is wrong: DangerIf the rotation direction is wrong: DangerIf the rotation direction is wrong: Danger

of severe compressor damage! of severe compressor damage! of severe compressor damage! of severe compressor damage! of severe compressor damage!

6.4 Schematic wiring diagrams6.4 Schematic wiring diagrams6.4 Schematic wiring diagrams6.4 Schematic wiring diagrams6.4 Schematic wiring diagrams

The following schematic wiring diagrams show ex-amples of application for part winding and star deltapart winding and star deltapart winding and star deltapart winding and star deltapart winding and star deltastart each with infinite and 4-step capacity con-start each with infinite and 4-step capacity con-start each with infinite and 4-step capacity con-start each with infinite and 4-step capacity con-start each with infinite and 4-step capacity con-trol.trol.trol.trol.trol. In addition optional control schemes for liquidinjection, economizer operation and oil level controlsare included.

CAUTIONCAUTIONCAUTIONCAUTIONCAUTIONMake sure that the rotation monitoring isMake sure that the rotation monitoring isMake sure that the rotation monitoring isMake sure that the rotation monitoring isMake sure that the rotation monitoring is

functioning! Tfunctioning! Tfunctioning! Tfunctioning! Tfunctioning! Terminal D1 of theerminal D1 of theerminal D1 of theerminal D1 of theerminal D1 of theINT69VSYINT69VSYINT69VSYINT69VSYINT69VSY-II must be connected-II must be connected-II must be connected-II must be connected-II must be connected

according to the wiring diagram. according to the wiring diagram. according to the wiring diagram. according to the wiring diagram. according to the wiring diagram. RemoveRemoveRemoveRemoveRemovethe jumper L/D1 at this time.the jumper L/D1 at this time.the jumper L/D1 at this time.the jumper L/D1 at this time.the jumper L/D1 at this time.

The following requirements must be ensured byThe following requirements must be ensured byThe following requirements must be ensured byThe following requirements must be ensured byThe following requirements must be ensured bythe control logic:the control logic:the control logic:the control logic:the control logic:

• Minimum time of standstill: 1 minute. Valid duringmaintenance also!Returning time of the control slide - CR3 (Y3)energized

• Maximum cycling rate 6 to 8 starts per hour!• Minimum running time desired 5 minutes!• Switch-over time part winding 0.5 seconds start

delta 1 second

Instruction for start delay timer with economizerInstruction for start delay timer with economizerInstruction for start delay timer with economizerInstruction for start delay timer with economizerInstruction for start delay timer with economizeroperationoperationoperationoperationoperation

The switching-on device F7 must ensure that therefrigerant flow to the liquid sub-cooler is not switchedon until operating conditions have sufficiently stabi-lized. This is achieved by using the solenoid valve Y6.

With frequent starting from high suction pressure, apressure switch should be sued. The set point shouldbe sufficiently above the nominal evaporating tempera-ture in order to prevent the economizer solenoid valveY6 from short cycling.

For systems with relatively constant pull down cycles(such as liquid chillers), an alternative is to use a timerelay. The delay time must then be checked individu-ally for each individual systems.

LegendLegendLegendLegendLegend

B2 Control UnitF1 Main fuseF2 Compressor fuseF3 Control circuit fuseF4 Control circuit fuseF5 High pressure cut outF6 Low pressure cut outF7 Start delay timer “Economizer”F8 Oil level switch (option)F13 Thermal overload “motor” PW1

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F14 Thermal overload “motor” PW2H1 Signal lamp “motor fault” (over temp / phase

failure)H4 Signal lamp “oil level fault”K1 Contactor “first PW” (for PW) “Mains contactor”

(Y/)K2 Contactor “second PW” (PW) “Start contactor”

(Y)K3 “Delta contactor” (Y))K4 Auxiliary contactor (option)K2T Time relay “pause time”K3T Time relay “part winding: or “star delta”K4T Time relay “oil level switch”K5T Fixed pulse relay “CR4” flashing function on / off

10 secondsM1 CompressorQ1 Main switchR1 Oil heater *R2 Oil temperature sensor (PTC) *R3-8 Motor PTC sensor *S1 On-off switchS2 Fault reset “motor & discharge temperature”

and/or “direction of rotation”

S4 Fault reset “oil level”U Screening unit (if required, such as from Murr

Elektronik)Y1 SV “capacity control” *Y2 SV “capacity control” *Y3 SV “capacity control” *Y4 SV “capacity control” *Y5 SV “liquid line”Y6 SV “refrigerant injection” alternatively

“econimizer”Y7 SV “economizer by-pass” INT69VSY-II

Control device for motor protection and discharge gas superheat protection *

SV Solenoid valve

* Parts are included with compressor

Capacity controlY1 CR1, Y2 CR2Y3 CR3, Y4 CR4

Figure 21Part winding start wiring diagram

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Figure 22Part winding start with 4-step capacity control

Figure 23Part winding start options

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Data for accessories and oil chargeData for accessories and oil chargeData for accessories and oil chargeData for accessories and oil chargeData for accessories and oil charge

• Oil heater: 115/230 VACSCH2 5000 to 9000 200WSCA2 3500 to 7000SCH2 11H0 to 14H0 300WSCA2 9000 to 11H0

• Capacity control:24/115/230 VAC 50/60 Hz

• Oil charge:Solest170 for R134a, R407C, R404A and R507ACP4214-320 for R 22

Oil heaterOil heaterOil heaterOil heaterOil heater

Ensures the lubricity of the oil even during long stand-still periods. It prevents increased refrigerant dilutioninto the oil and therefore reduction of viscosity.

The oil heater must be used during the shutdown for• outdoor installation of the compressor (insulate the

oil separator additionally if necessary)• long off cycles• high refrigerant charge• danger of refrigerant condensation into the

compressor

10 Performance data10 Performance data10 Performance data10 Performance data10 Performance data

For detailed compressor selection with the option ofindividual data input our selection software is availableas CD-ROM or can be downloaded from our internetweb site. The resulting output data include all impor-tant performance parameters for compressors andadditional components, application ranges, technicaldata and dimensional drawings. Moreover, specific datasheets can be generated which may either be printedout or transferred into other software programs, suchas Excel, for further use.

Basic parametersBasic parametersBasic parametersBasic parametersBasic parameters

Evaporating and condensing temperatures correspondto “dew point” conditions (saturated vapor). Withzeotropic blends like R407C this leads to a change inthe basic parameters (pressure levels, liquid tempera-tures) compared with data according to “intermediatetemperatures” used so far. As a consequence thisresults in a lower numerical value for cooling capacityand efficiency (COP).

Liquid sub-coolingLiquid sub-coolingLiquid sub-coolingLiquid sub-coolingLiquid sub-cooling

With standard conditions nonononono liquid sub-cooling isconsidered. Therefore the rated cooling capacity andefficiency (COP) show lower values in comparison todata based on 9 or 15°F of sub-cooling.

Economizer operationEconomizer operationEconomizer operationEconomizer operationEconomizer operation

Data for economizer operation system inherentlyinclude liquid sub-cooling. The liquid temperature isdefined as 18°F above saturated temperature (dewpoint with R407C) at economizer inlet (tcu = tms +18°F).

10.1 Compressor selection by software10.1 Compressor selection by software10.1 Compressor selection by software10.1 Compressor selection by software10.1 Compressor selection by software

• Select the menu CSH Compact Screws.

• Type the desired Cooling Capacity.

• Select desired operating conditions:-Refrigerant and for R407C-Reference temperature-Evaporating temperature-Condensing temperature-Without or with economizer-Liquid Sub-cooling-Suction Gas superheat or suction gas temp.-Useful superheat-Power supply

• Hit Calculate.In the window Output Data the selected compres-sors with performance data are shown (fig. 24).

• Data output:At this stage an input of individual text (Head line)is possible.

- Print: Print-out at standard printer, withapplication limits (application ranges)

- Export: Output as ASCII file

10.2 Finding compressor performance data using10.2 Finding compressor performance data using10.2 Finding compressor performance data using10.2 Finding compressor performance data using10.2 Finding compressor performance data usingthe softwarethe softwarethe softwarethe softwarethe software

• Select the menu CSH Compact Screws.

• Select Compressor Type.

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• Select the desired operating conditions:- Refrigerant and for R407C reference

temperature- Evaporating temperature- Without or with economizer- UCT. gas superheat or suction gas

temperature- Useful superheat- Capacity regulator- Power supply

• Hit Calculate.In the window Output Data the selected compressorwith performance data is shown.

• Data output:at this stage an input of individual text (Head line)is possible.- Print: Print out at standard printer, with applica-

tion limits (application ranges)- Export: Output as ASCII file

Operating point in application limits diagram• Hit Limits.

Standard application limits diagram with operatingpoint (blue cross) is shown in the window.Further window: application limits diagram for ECO.

TTTTTechnical data of a compressorechnical data of a compressorechnical data of a compressorechnical data of a compressorechnical data of a compressor• Hit T. Data.

Window Data appears, in which the technical dataare listed.Further windows:Dimensions (dimensional drawing and Notes (notesand legend)

• Export all data with Print (Print-out at standardprinter, or Export (as ASCII file).

Export performance tables• Hit Tables.

The blank Performance Table is shown in thewindow.

• Check the default values (white fields) and changewhere necessary.The Input Values can only be changed in thewindow Single Point Calculation.

• Hit Calculate.The Performance Table is shown in the window.

• Export the data with Print (print-out at standardprinter, Export (as ASCII file) or Copy into theclipboard).

Copeland is a registered trademark and CopelandScrew is a trademark of Copeland Corporation. The

Emerson Climate Technologies logo is a trademark andservice mark of Emerson Elelctric Co.

Copeland Screw Compressors Semi-Hermetic Compact ...

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