Variable Speed Drivesfor HVAC Applications

1 - 75HP 208 - 240VAC • 1.5 - 500HP 380 - 480VAC

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Air-Modulator cutsair-handler energy costsup to 60%Variable air volume (VAV) control isthe most cost-effective approach to HVACair-handling design. By matching air volumeto actual cooling loads, VAV cuts air-handlerenergy consumption 20% to 60% versusconstant air volume systems.But choosing a VAV system design is onlyhalf of the decision. The other half ischoosing the most efficient type of fan volumecontrol - the Air-Modulator from YORK.

Air-Modulator: the most efficientVAV technologyIn order for a fan to vary its air volume,expressed in cubic feet per minute (CFM),it must either be mechanically throttledor its speed must be controlled. Whilemechanical fan volume controllers, suchas discharge dampers and variable inletvanes can reduce fan energy consumptionsomewhat, they cannot match the savingsobtainable with the Air-Modulator electronicvariable-speed control.That’s because the Air-Modulator takesmaximum advantage of the relationshipbetween fan speed and fan horsepower.With the Air-Modulator, any given reductionin fan speed results in a cubic reduction infan horsepower. For example, a 10%speed reduction means a 27% horsepower

reduction. A 50% speed reductiontranslates into an astounding 87%horsepower decrease. Such savings farsurpass what is offered by mechanicalcontrol devices.

Savings that multiplythroughout the building andthroughout the yearTo appreciate the impact of thesenumbers fully, consider how a VAV airhandler operates. It runs many hoursthroughout the year, but seldom at itsfull-load air flow. Instead, the majority ofits operating hours are spent at partial airflows, which is where the Air-Modulatoroffers its greatest savings.Multiply the Air-Modulator savings timesthe operating hours times the number ofair handlers, and the building energysavings become dramatic.

Air-Modulator allowsenergy-efficient operationduring off-peak periods,which typically account for98% of total operatinghours.

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Air-Modulators payfor themselvesIs the Air-Modulator a good investment? Withan ROI as high as 100%, the Air-Modulatorcan pay for itself in as little asa year with the energy savings it offers.Thereafter, the savings go directly into thebottom line. How many investments offeryou that kind of return?

The perfect choice for retrofitsThe Air-Modulator is the perfect choice forretrofit on air-handling equipment fromYORK, Carrier, Trane, and other majorsuppliers. Its small size fits easily intocrowded equipment rooms, and can bemounted on a wall remote from the fan.

For more than air handlersAir handlers aren’t the only HVAC equipmentthat can benefit from theAir-Modulator. Chilled-water pumps canalso be operated at variable speeds byputting two-way valves on the chilled-watercoils and Air-Modulators on the pumps.The savings for a constant speed pumpis potentially similar to that for a constant-speed air handler.

Cooling towers benefit, tooYORK’s extensive experience inoptimizing cooling tower and chillerperformance proves that optimum chillerplant power consumption is achieved byminimizing entering condenser watertemperature, therefore, tower fans areemployed over a large portion of theoperating hours. Energy savings canbe achieved when:• Wide swings occur in outdoor

ambient temperature• Chillers operate at low loads• 24 hour chiller plant operation is required

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Compatible with standard motorsand controlsThe Air-Modulator is engineeredspecifically for HVAC, so it’s directly compat-ible with standard HVAC pneumatic and electriccontrol signals. And there’s no need forspecial high-efficiency motors. The Air-Modulatoris easily applied to standard motors, makingretrofit easy and less expensive.

Less fan noisefor greater comfortThe benefit of energy savings means nothingif the VAV system creates disruptive noisethat disturbs building occupants. Unlikemechanical fan control devices (such asvariable inlet vanes and discharge dampers),the Air-Modulator has no air-flow obstruc-tions, so it’s quieter than any mechanical fancontrol method.Also, because the fan runs slower, it runsquieter. Measured sound levels can be asmuch as 75% lower if the Air-Modulator isused instead of mechanical control devices.

Less motor noise, tooMany variable-speed drives can set upvibrations within the motor, causing a high-pitch whine.The Air-Modulator uses the latest electronictechnology to reduce this motor noise by upto 85%. This is especially important whenmotors are mounted inside air handlerswhere motor noise can easily enter theair stream and building spaces.

Quick air balancing savestime and moneyWith the Air-Modulator, fan speed canbe adjusted “in-flight” and with electronicprecision, making air system balancingquicker and more accurate. No more shuttingthe fan off every time a pulley adjustmentis needed and then “guesstimating” howmuch of an adjustment to make. Plus,the Air-Modulator eliminates the need forexpensive and troublesome adjustable speedpulleys.

Air-Modulator is designedspecifically for HVAC

As variable inlet vanes closethey obstruct the air flow…

…increasingairborne noise.

Current-limiting capabilityeliminates the need forexpensive fansBecause the Air-Modulator can beset to limit amperage draw, expensiveairfoil fans with their non-overloadingcurrent-draw characteristics are no longerneeded. Instead, less expensiveforward-curved fans can be used.

Air-Modulator’s current-limiting capabilityeliminates the need forexpensive airfoil fans(foreground), permittingthe use of less expensiveforward-curved fans(background).

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Reduces maintenance costs -extends equipment life

Solid-state reliabilityMechanical fan control devices typically require costlymaintenance. Not so with devices using solid-stateelectronics, where there’s nothing to adjust, nothing tolubricate, and nothing to wear out. In short, the Air-Modulator requires limited routine maintenance and isinherently reliable for trouble-free operation.

Built-in protection and easy faultdeterminationThe Air Modulator drive guards against such damagingelectrical characteristics and disturbances asovercurrents, overloads, overvoltages, overheating, groundfaults, phase loss, and short circuits. It shuts itself downsafely, and will automatically restart when the fault orproblem is cleared. To aid in troubleshooting of the Air-Modulator, the exclusive YORK keypad will display inEnglish language the cause of the drive fault or problem.With a unique HELP key the drive will guide the user topossible solutions to the problem. This feature is likehaving an on-line, built-in troubleshooting guide andmanual right on the keypad display.

Soft start extends equipment lifeUnlike conventional motor starters, the Air-Modulatorprevents the sudden current surges that shock motorsand drives during start-up. Starting the fan slowly, andbringing it up to speed gradually, reduces the stresses onthe equipment. The result is prolonged motor, belt, pulley,and bearing life.

The reduced drive stress is even greater when the air-modulator is applied to cooling towers. A tower equippedwith fan cycling control will see numerous cycling startsevery day. If the tower fan is equipped with an Air-Modulator, its gentle ramping start will extend the life of thefan drive components, especially the gear box.

YORK service-expertise in bothelectronic and HVAC systemsWith YORK, you receive single-source service expertisein both electronic controls and HVAC systems, from thecompany that introduced HVAC speed controls in 1978.No finger-pointing, no hassles, and no runaround. Even ifthe Air-Modulator is installed on competitive equipment,we’ll take maintenance responsibility for both, giving youone less potential headache.

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New advanced controlpanel for easy operationand complete control

Intuitive to operateBig bold displayReal time clockParameter backup and restore

Interactive maintenanceassistantMaintenance scheduling no longerrequires guesswork. The HVACdrive alerts you when maintenance isrequired based on your individualrequirements.

Interactive diagnostic assistantShould a fault occur, the diagnosticassistant displays, in plain language,possible causes and potential solutions.

Built-in timersExternal time circuits are no longerneeded. Built-in timers - utilizing thereal-time clock - allow starting andstopping the drive or changing thespeed according to the time of day ornight. Relay outputs can be operatedwith timers to control any auxiliaryequipment on site.

Pre-configured HVAC applicationmacros14 different HVAC application macrosare pre-programmed into the HVACdrive. Application macros for supplyand return fans, cooling tower fans,booster pumps and condensors areavailable, just to name a few. The usercan create two additional applicationmacros, selectable manually or througha digital input. To illustrate this, theuser can create “summer” and “winter”application macros and select betweenthese according to the time of the year.

Fault loggerThe fault logger of the HVAC driveis especially useful in trackingdown drive trips through its use ofthe real-time clock. In addition torecording both time and date, thefault logger also takes a snapshotof 7 diagnostic values - like motorspeed and output current. Youknow what happened and when.

N2, FLN, Modbus, andBACnet embeddedCommonly used HVAC fieldbuses areembedded into the memory of the drive,ensuring that they are always there if youneed them. YORK has a long history inbuilding automation, with thousandsinstalled drives utilizing serialcommunications.

LonWorks and ProfibusLonWorks, Profibus and other plug-inmodules fit under the cover of the drive.A single twisted pair avoids great lengthsof conventional cabling, reducing costand increasing system reliability.

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Built-in EMI/RFI filtersThe AYK Series Drive meets the EMCproduct standard EN61800-3 for the 1stEnvironment. These filters eliminate theneed for any additional external filteringhardware.

Swinging reactor - up to 64% lessharmonicsPatent-pending swinging choke meansthe AYK Series Drive reduces harmonicsby up to 64% at partial loads whencompared to a PWM AFD with nochokes. There is no need to oversize thesupply cables.

Two PID controllers as standardThe HVAC drive has two independent PID controllersbuilt in. As an example: one PID controller works withthe AFD to maintain the duct static pressure;simultaneously, the other PID controller can be used tocontrol a separate external device, e.g. a chilled watervalve. All of this can, of course, be monitored andcontrolled through serial communications.

Compact sizeReduced size for ease of mounting

Flux optimizationThis standard feature means thedrive supplies only the voltage andcurrent necessary to drive the load.This results in reduced energyconsumption and much lower motornoise levels. Silent operation modefurther reduces motor audible noisefor sensitive applications.

The motor can deliver full output at 40oC - shouldn’tthe AFD to the same?YORK’s HVAC drive is rated for continuous operation to 40oC withfull current, without being compromised by temperature variationswithin any 24-hour period. Full circulation is available, preciselywhen needed - usually when it is hot outside. At 50oC, only 10%de-rating is required for UL Type 1.

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Top 10 Selling Features

The following key points are unique selling features to the YORK AYK550 Air-Modulator. These features should beemphasized to consultants, engineers, architects, and end users as they provide exceptional value and reliability comparedto other VFDs on the market.

#1 New "Swinging DC Line Choke"• Equivalent to 5% Input Line Reactor• Designed to reduce harmonics at full andpartial

loads• Perfect for variable torque centrifugal loads• More inductance per volume/weight

#2 Improved Built-In RFI/EMI Filter• Meets EMC EN61800-3 for First Environment

restricted distribution 30 meter cable length• CE marked for EMC compliance

#3 High Input Transient Protection• 4 MOVs ahead of diode bridge for surge

suppression• 120 Joule rated 1600V diode module.• Complies with UL 1449 ANSI 61.4

#4 New Current Measurement Technique• More accurate signal for kW, Amps, kWHr• More accurate metering at low loads

#5 Enhanced Control Board• Fireman's override circuit for tie in to building fire

management systems• 2 programmable analog outputs• 6 programmable digital inputs• 3 programmable relay outputs (Form C)• More EEPROM memory with enhanced software• Faster responding analog and digital inputs• Standard run permissive circuit to operate

dampers before motor operation

#6 Advanced Numeric Keypad with:• Start up, diagnostic and maintenance

assistants• Real-time clock• Full graphic display with big bold letters• Displays 3 process variables for

monitoring• Dedicated HELP key• Backup and restore copy function• Hand - OFF - Auto and Speed Up/Down

buttons• Intuitive to operate

#7 New Fault Logger• Real-time "snapshot" of last 3 faults

- fault name, time, speed, frequency, voltage, current, torque, DI status

• Logs up to 10 faults with fault name only

#8 Built-in Serial Communication Protocols• Siemen's FLN, Johnson N2, Modbus

RTU, and BACnetAll embedded in firmware as standard

• LONworks available as an option

#9 Optimized Cooling Fan Design• Logic controlled on/off operation tied to

VFD operation• Easily removable with one connection• Complete fan change out in less than 1

minute

#10 High Fault Current• UL rated to 100,000 AIC at 460VAC• Package will meet demands of today's

electrical systems• Applies to Base Drive, AO, and CM

options only. Factory mounted drivepackages require SQ from YORKMarketing for High Fault Withstand.

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YORK Package ConfigurationsThe following Air-Mod configurations are available as standard product offerings:

Base Drive

"OO" Configuration

• AYK550 VFDNEMA 1 Rated

• NEMA 1 Conduit Box

• 100,000 AIC FaultCurrent Rated

Base Drive withFused Disconnect

"AO" Configuration

• AYK550 VFDNEMA 1 Rated

• Fused Main Disconnectwith Pad Lockable Handle

• 100,000 AIC FaultCurrent Rated

Base Drive with Bypass,VFD Service Disconnect,Main Fused Disconnect

"CM" Configuration

• AYK550 VFD NEMA 1 Rated

• Main Fused Disconnect Switchwith Pad Lockable Handle

• VFD Input Service Disconnect Switchfor Isolation During Repair

• 2 Contactor ByPass

• Class 20 Motor Overload

• Control Transformer

• VFD/Off/ByPass Selector

• Power On/Bypass On Pilot Light

• 100,000 AIC Fault Current Rated

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More than just a drive . . .it’s a Unitary Controller

1) The BMS commands start/stop; internal/external PID setpoints; command digital(relay) outputs, and analog (4-20mA)outputs and reset faults. The BMS readsdrive outputs; controlled variable feedback;Hand/Auto selected indication; kWhrs (R);Operating hrs (R); drive amps (broken beltindication); drive temperature; all warnings,faults, and much more.

2) Receive and monitor hard-wired devices -firestat/freezestat safety contacts, smokepurge commands - over the serial link.

3) Open an isolation damper, override a VAVbox or any device that requires a maintainedcontact closure for control. Receive damperend-switch proof contact.

4) The Keypad Display indicates feedback and setpointin inches of water column - or programmable unitsintuitive to the user.

5) BMS commands a drive analog output to controlhot or chilled water valves or any device requiringa 0-20mA input.

6) The drive’s external PID Loop Controller controls achilled water valve or any device requiring a 0-20mAinput. Feedback signal is hard-wired to AFD andsetpoint is sent via serial comms.

7) Use the drive’s process PID Loop Controller tomaintain supply fan pressure via adjusting fan speed.Pressure feedback is hard-wired to AFD and setpointis sent via serial comms.

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Keypad & FirmwareFeatures

The new AYK Series Drive Keypad takes the typicaloperator interface to a new level.

YORK AYK Series Drive Keypads use full language,no codes. And this keypad emulates the humaninterface of a cell phone. Easy as a mobile phone,and you control a panel with intuitive handling in 14languages.

The new YORK AYK Series Drive has pioneeredseveral new-to-the-market features such asMaintenance Assistants, Diagnostic Assistants,Programming Assistants, and Help Screens.

For example, if there’s a trip off line, pressing the HelpKey brings the user to the Diagnostic Assistant; itsuggests possible causes of the trip and probablecorrective actions.

Programming Assistants configure the drive for anapplication. For example, the PID Assistant prompts

the user through a series of 12 questions; and uses theanswers to these questions to set 26 parameters inside ofthe drive’s program. No need to navigate the drive menus!

The Maintenance Assistant alerts users when equipmentmaintenance is required, based on selected inputs. Utilizethe Revolution Counter and Maintenance Assistant to signalpersonnel when it’s time to replace the pump packing.

The Keypad features two soft keys; their functions changeaccording to the operating state of the panel. Hand-Off-Auto buttons provide local control for local-speed and start/stop control.

The Help Button brings up a description of what the effectof parameter changes would be - in full sentences!

Faults can be time and date stamped via the real-time clock.A fault logger stores status information such as amps, volts,and presence of a run command at the time of the fault.

What people are saying . . .Facility Managers“With YORK’s standard built-in hardware like the 5%swinging choke and the EMI / RFI Filter, I know that anysensitive equipment in my facility will not be adverselyaffected by drive operation.”

“I love the Help Button. I call itmy panic button - it quitesimply is always available toguide me with usefulinformation.”

“The Maintenance Assistant is another great feature of theDrive. I simply do not need to worry about when it is timeto service the equipment. The drive tells me when it is timeto send people to perform maintenance.”

Temperature Control Contractors“YORK understands the HVAC Market. I save time andmoney because I do not need to supply interposing relaysand control logic to accomplish ‘real world’ functions suchas Fireman’s override and damper end-switch proof.YORK has these and many more features built-in.”

“The YORK AYK Series Drive is actually a drive andunitary controller in one. I have 13 free I/O points withevery YORK drive provided.

“The second PID loop built into the YORK HVAC Driveallows me to control cooling tower bypass valves or othercontrol valves with no additional hardware or cost.”“The YORK HVAC Drive is a Temperature ControlsEngineer’s dream . . .on-board passthrough I/O, a freePID loop controller, and broken belt indication. Damperend-switch and smoke purge controls are built-in at noadditional charge!”

Specifying Engineers“The 5% swinging choke means I do not need to oversizemy supply transformer and cables to meet NEC 430-2.”

“Specifying a drivethat meets EMCproduct standards forthe First Environmentmeans I will not havejob site EMI / RFIissues or complaints.”

“The built-in communications suite means I can haveintelligent drive applications regardless of whichtemperature control contactor is successful on theproject”

“YORK supplies submittal packages that provide thedetailed information and drawings I need to verify quicklythat the YORK drive meets my specification requirements.That information saves me a lot of time.

Contractors

“With the Hand Macro, I can move air to dry out the newconstruction paint and drywall mud without calling for acertified start-up. There’s no need for multiple trips to myjob site by the YORK Technicians to commission thedrives, and that saves me money.”

“YORK AYK Series Drive enclosures are UL Listed andUL Plenum Rated. I can mount the drive in most locationswithout worries.”

“I don’t have to search for external components like timersand PID controllers and then worry about theircompatibility. It’s all there, in the drive.”

“A keypad that functions like acell phone - what could be easier”

“Finally, a BACnet-compatible HVACdrive without the need for expensive andunwieldy third-party gateways.”

“When I call YORK, I knowI get the right answer”

P.O. Box 1592, York, Pennsylvania USA 17405-1592 Subject to change without notice. Printed in USACopyright © by York International Corporation 1997 ALL RIGHTS RESERVEDForm 100.42-SG2 (305)New Release

Tele. 800-861-1001www.york.com