83449188 NEMA SM 23 1991 Steam Turbines for Mechanical Drive Service

8/13/2019 83449188 NEMA SM 23 1991 Steam Turbines for Mechanical Drive Service

1/64

NEMA Standards Publication No. SM 23-1991 (R1997, 2002)Steam T urbines for Mech anical Drive Se rvice

Published by:National Electrical Manufacturers As soc iat ion1300 North 17th Street, Suite 1847Rosslyn, VA 22209

O Copyright 2002 by the Na tional Electrical Manufacturers Association. All rights includingtranslation into other languages, reserved under the Universal Copyright Convention, the BerneCon vent ion for the Protection of Literary and Artistic Works, and the international and PanAmerican Copyright Conventions.

right National Electrical Manufacturers Association

ded by IHS under license with NEMA Licensee=Defense Contract Mgmt Command/5935922100Not for Resale, 09/18/2006 02:36:51 MDTproduction or networking permitted without license from IHS

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NOTICE AND DISCLAIMERThe information in this publication was considered technically sound by the consensus ofpersons engaged in the development and approval of the document at the time it wasdeveloped, Consensus does not necessarily mean that there is unanimous agreementamong every person participating in the development of this document.The National Electrical Manufacturers Association (NEMA) standards and guidelinepublications, of which the document contained herein is one, are developed through avoluntary consensus standards development process. This process brings togethervolunteers and/or seeks out the views of persons who have an interest in the topic coveredby this pub lication. While NEMA administers the process and establishes rules to promotefairness in the development of consensus, it does not write the document and it does notindependently test, evaluate, or verify the accuracy or completeness of any information orthe soundness of any judgm ents contained in its standards and guideline publications.NEMA disclaims liability for any personal injury, property, or other damages of any naturewhatsoever, whether special, indirect, consequential, or compensatory, directly or indirectlyresulting from the publication, use of, application, or reliance on this docum ent. NEM Adisclaims and makes no guaranty or warranty, express or implied, as to the accuracy orcompleteness of any information published herein, and disclaims and makes no warrantythat the information in this document will fulfill any of your particular purposes or needs.NEMA does not undertake to guarantee the performance of any individual manufacturer orsellers produc ts or services by virtue o f this standard or guide.In publishing and making this document available, NEMA is not undertaking to renderprofessional or other services for or on behalf of any person or entity, nor is NEMAundertaking to perform any duty owed by any person or entity to someone else. Anyoneusing this document should rely on his or her own independent udgment or, as appropriate,seek the advice of a competent professional in determining the exercise of reasonable carein any given circumstances. Information and other standards on the topic covered by thispublication may be available from other sources, which the user may wish to consult foradditional views or inform ation not covered by this publication.

O

NEMA has no power, nor does it undertake to police or enforce compliance with thecontents of this document. NEMA does not certify, test, or inspect products, designs, orinstallations for safety or health purposes. Any certification or other statement ofcomp liance with any health or safety-related information in this document shall not beattributable to NEMA and is solely the responsibility of the certifier or maker of thestatement.

right National Electrical Manufacturers Associationded by IHS under license with NEMA Licensee=Defense Contract Mgmt Command/5935922100

Not for Resale, 09/18/2006 02:36:51 MDTproduction or networking permitted without license from IHS

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NEMA SM 23


Not for Resale, 09/18/2006 02:36:51 MDTeproduction or networking permitted without license from IHS

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4/64

NEMA Standards PublicationNo. SM 23-1991 (R1997)Steam Tuhines for Mechanical D i v e Service

Published by:National Electrical Manufacturers Association1300 North 17th Street, Suite i 47Rosslyn, VA 22209

Q Copyright 1997 by the National Electrical Manufacturers Association. All rights includingtranslation into other bng uages , reserved under the Universal Copyright Convention, th e BerneConvention for the Protection of Literary and Artistic Works, and the International and PanAmerican Copyright Conventions.

yright National Electrical Manufacturers Association

ded by IHS under license with NEMA Licensee=Defense Contract Mgmt Command/5935922100Not for Resale, 09/18/2006 02:36:51 MDTeproduction or networking permitted without license from IHS

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5/64

~~

S T Q - N E M A S M 2 3 - E N G L 1991 6470247 0524297 714 m

TABLE OF CONTENTSFOREwom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .RefaencedSEancbrrds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Definithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .sectm2 CONSTRUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .' I ) p e s o f S t e a m T . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .CiassiedbyExhaustcaiditiasis............................... N Ti abmc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .CoadensingTUrbinc ...................................classifiedby Number of Stages andCoam1Valves . . . . . . . . . . . . . . . . . . . .SingleValveSingieSEagC'Iirrbint............................Single Vaive MuuistegeMine .............................Multi* sil@ stagemine . . . . . . . . . . . . . . . . . . . . . . . . . . . .Muitivaive Muitisiage'ixine . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

C i a s s i d b y ~ N e e d s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .controlled (Alumtic)ExeractionTurbine .......................NoncwtrolletiExtractiosi nlrbhw . . . . . . . . . . . . . . . . . . . . . . . . . . . .CmmUed InQiCtim (Mixdnesslire)M e ....................InductimExtractionTirrbine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .SteamII iab inecc tUl~ts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Turbinecasmg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .SteamInletEndseCtion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ExhaustEI?dstction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Irlemedia&sactiw ...................................

SteamRing .........................................StatiomyReveEngBladcs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Diciphragm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .sw. lrbirbe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ImpuIseStage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .shaftseals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .casingshaftseals .....................................Intemagestlaftseals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Bearings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ThnistBearings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .AntitiCtianBearings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .RotorAssembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .wheels@iscs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Shroud . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .COnmhgDevi~ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ExtemalcontrolDevice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .WamingDeVice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .REFERENCEDSTANDARDS AND DEPlNlONS ....................ectkn 1

Noacontrolled Induction 'linbine . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Steam Chest (GOV~IIKNaheBody) . . . . . . . . . . . . . . . . . . . . . . . . . . . .Nozzles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .StationaryRevczsingCham~ ..............................

ReactianS age ......................................BearingHousing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

RacaiBcarings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Biades(Buckets) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Handvalve@) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .RotectiveDevice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

PiSciii11133333333333333333333444444444444444455555555555



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plrsectlocr2 SentinelW h g alve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5soleplate(s) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Basephte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6FeatmsandAccessan es ................................... 6BasicFeaMesaQd- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6OptiOnalFeaMesandAccessorics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6c o n t r o n e d ~ ~ a n d c o n t r o l l e d ~Itrrbines. . . . . . . . . . . . . . . . . 7NcmwntroiledExach Turbhes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Nonconp.olled I nducti ai I l abi nes ............................. 7?IiirbineRating......................................... 7power ............................................ 7speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Ratedspeed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Maximum continwus peed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7N d ower end Speedand SteamCaiditions . . . . . . . . . . . . . . . . . . . . . 7Stcamconditiaas: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7MinimwnSteam(hKiibS ............................... 7MaximumStcamconditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7MinimumEnergystcamccmditions . . . . . . . . . . . . . . . . . . . . . . . . . . 7Inlets eampressure ................................... 7ExhaiistSteampressUre . . . . . . . . . . . . .. . . . . . . . . . . .. . . . . . . . 8Extraction SteamRressiire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8InductionSteam Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Inlet Steam Tempemure . . . . . . . . . . . .. . . . . . . . . . . .. . . . . . . . . . 8ExhaustSteamT~erame . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8ExtiactionSteamTemperatrae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8LndpctimSteamTempgatme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8MaximumMowableWorkingPressuresandTeanptmtms . . . . . . . . . . . . . . 8DualSteamconditions ................................. 8VauiationsinSteamconditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Flow LimitsforanAutomatic Exaaction? M i h e . . . . . . . . . . . . . . . . . . . 9HowrjmitpforanInductionTurbine. . . . . . . . . . . . . . . . . . . . . . . . . . 9Units of Measurement forAbsolute and GaugePressure . . . . . . . . . . . . 9Thermodynamic?Iienns . . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . 9SteamRateS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

I TheOretidSteamRate ................................. 9ActualsteamRates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10GuaranteedSteamRate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10?Iiirbineconnectiais ..................................... 10outputshaftExte~. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10S t e a m c o h u s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10AuxiliaryconnectionS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10LlbiClUb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10NonpFessure?lSpeLubncation Single stage lbbines) . . . . . . . . . . . . . . . . . . 10

o l LulnicztredsleeveBeanngs (HarizwEalTi i rbi nes . . . . . . . . . . . . . . . . . 10G?easeoroillubricatadAntinictionBearings ..................... 10p r e s s u r e ? l s l p eo i lL u~............................... 11InProduction ....................................... 11Oilnrmpr . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11oilReservoir ....................................... 11oilcooler ........................................ 11OilFdt~zs ........................................ 11

yright National Electrical Manufacturers Associationded by IHS under license with NEMA Licensee=Defense Contract Mgmt Command/5935922100


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S T D - N E M A SM 23-ENGL L99L b470247 0524299 5 9 7 =section2 piping andInstnunentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .nwisonsfor heEsrvin>nment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Eaclosufe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Exposwe toNanrral Elements ...............................Exposure toAbnonnalAhnphedic conditioas . . . . . . . . . . . . . . . . . . . . . .GeneraiRequiremeats .....................................PltsSureandTempemmRanges . . . . . . . . . . . . . . . . . . . . . . . . . . . . .vi brati on ..........................................Singlestagerbim ..................................M d t i s t a g e r b ~...................................clitwspeeds. ..................................NameplateData . . . . . . . . . . . .. . . . . . . . . . . .. . . . . . . . . . . .. . .Sedkn 3 CONTROLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .GoveaningSystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .S p e e d G O m r . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .GOv morcon mlled WVe(S) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ServomomSystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Speedcbangetlype . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .speedchanger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .SpeedGovaning System classification . . . . . . . . . . . . . . . . . . . . . . . . . . . .SpeedRange . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Maximums@Rise . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . . .speedvariation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .DeadBand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Speed Regulation. Steady State ..............................steamPressurecaritrd ....................................PressureRegUlatingSysea~. . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . .PressureRegUlatw . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ControlMechaniSn .....................................nessUre ControlledWves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .pressurechanger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .SteadyStatePxess~mReuuion ..............................PressureReguiatioaiC ...........................stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .pressure controlperfamilmce . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Compensatedcoatrol System .................................Electronic Governing System .................................Basic Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Accessones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ControlPrimiries .....................................Controlof inuctimorExtracoon ............................Missing Signai Detection Featrae . . . . . . . . . . . . . . . . . . . . . . . . . . . .SensorRedundancy ...................................OverSpeeaTnp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Genexal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Automatic S t a t Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Multivariable Govexnor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .CoatmlMeChanism . . . . . . . . . . . .. . . . . . . . . . . .. . . . . . . . . . . ..E x t e m a l C d D e v i w . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

RemoteSetPointQpe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Valve Actuating- ..................................

.11121212121212121212131317171717171717171717171717181818181818ZQmm202020A)21212121212121212222222222

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STD.NEMA S f l 23-ENGL 1991 m b 4 7 0 2 4 7 0524300 039

s e c t h 4 PRECTiON . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . . ..BasicFeaues .........................................UanUalTrip .........................................Overspeed'LtipSystem ...................................O v e r s p e e d S c n s i n g D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .n i p s eed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .nipvalve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Combined Ltipand hrottlt Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . .overspeednipsystemsetting ...............................secSIon5 FACIDRYTESTING . . . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . .'Iiirbine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .HydroTd ..........................................NoLoadRUnmngTesc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Sectbn6 SOUNDPESSUREJEVELS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Gtaeral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .swnd3essweLev& .....................................s o S m d ~ L e v e l M t a s u r e m c n t p r o c e d m e .......................CamctionforBacLgrwndNoise ...............................

souadResolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .I nstnuneats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .S d A e n o n .......................................sectm7 PRapARATI0NFORS"TANDSTORAGE . . . . . . . . . . . . . . . . . . . .S h i j l p i D g R e ~. . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . .Shipneat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .W i t ndStorage of Equipmeat ..............................sectkn8 INSTALLAIION .......................................In-tion ...........................................SupervisionOfIaseallation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .steam Inletand ExhaustPiping...............................C i e a m n g o f ~ S t e a m P i p i n g . . . . . . . . . . . . . . . . . . . . . . . . . . . .SteamPipingSystems .....................................I n e t i o n .........................................ThePipingnoblemasApplied to?brbinesFbmsDue to StearnPressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .FbmsDue toTemperatwe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .FarcesDue toDeadWeight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .AuowaMe FcesandMoments onSttamTurbines ....................DrainPiping ..........................................Iak-ofli ...........................................Fuil-FiowReii&Device ....................................CoUptingAlignmcnt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Grwting ............................................FlushingiiSystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .In-tim . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

...........................................Fouudation .........................................

. . . . . . . . . . . . . . . . . . . . . . . .

............................eCtrOn9 OPERATONANDMAINTENANCEoperatioa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Noncondensing hbine opetatianofaMultisragecondensiag'Ihrbine'I)picalSEertmgSeqaence ima Steamnirbine ........................Maintlmance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Intluduction .........................................

. . . . . . . . . .

p.pc2323232323232323232525252527n27272828282931313131333333333333343636363638404142424244444451515151515151



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pigeSe Ct k n S UitemalWaterWashing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52steamhinty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52Sacth10 INQUIRYGUIDE.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67



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S T D * N E M A S U 23-ENGL L99L 9 6470247 052430il 7 D l W

ForewordI lhis standard has been developed by the Steam wbiine Section of NEMA. In its preparationandrevision,considaation as been given to he work ofother organizations. such as heAmericanNational Standards nstitute, theAmericanPeuoleum institute, the AmericanBoilerManufacturas

Association, and the Amencan SoCiety of Mechanical Engineers, striving toward the deveiopmentofstandards,anddtishaebygiventoaii whosesiandardsmayhavebeenh~~inthepreparatianof this publication.nK urpose of this standard f a ingiestage and multistage mech anid drive steam turbinesisto faciiitate the appiication of the.se turbines by engineers, users, aad conuactas, to promoteecwomieS m driving rotalhg mechanical equipment, and to assist in the proper seiection andapp~ofthedifferingmechantcal esignsof turbines.NEMA Standards P u b l i aSM23-1991revisesand SupeISedestheNEMA StandardsPubli-CationSteam Turbi nesfor Me~hanical )rive S e M e , SM 23-1985.User needs have been considertd hroughout the development of this standard. ProposedMrecommmdedrevisionsshouldbe submittedto:ViceResident,Engineering DepamnentNationalEiecaicalManufacturersAssociation2101 L S l E aNw, uite 300Washnigton,DC 20037(202)457-8400

1



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ii


Not for Resale, 09/18/2006 02:36:51 MDTproduction or networking permitted without license from I HS

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Section 1REFERENCEDSTANDA RDS AND DEFINITIONS

AmtriamNationolStandandsInstitute1430BroadwayNewYork,NY 10018S1.4-1983s1.11-1%ANSUASMEB16.1-1989B16.5-1988B1.20.1-1983B31.1-1989

Spcjf icpr ion or SoundikwlMetersSpe@hations for Octave-Bad, Fractional Octaw-Band Anolog MdD g M FmsCan ron Pipe Flangesmid Flanged Fttings,Class25,125,250anpiPC F b g e s andFlrurged F&gsGeneralPurpose Pipe ThrecuFr (Inch)PowcrPpng

J h t lilrinnfactprorsAssociation25 North Broadway-,NY 10591The S t a d a d sf he IIqmsion Jont Matu actmrs AssocirrtiOn (1980)(198sAddendum).

Riuiont-An -t deviarian inSMcaiceaoicityiodicattdbytheoatputofaprmimityprobcwhichisduetovariatiaas in theelectricalcondllctivjtymagnetiCpopertiesOfthtobsavedshaftsraface.volume of steam bappad betweem the turbine and a tripvalve ur no tmew Valve.atspeedsgreaterthan he first ateralc r i h i speed.

Hmting-Te oscillationof speed or other c011PD)ledpamnmx above andbelow the mean vaiue. An MsEablecoaditioll.smecontainingcompentsof he turbinebypressip1pagwith water.ntemaiWaterW~g-Aproceduremwhichsteamhaving a high percentage of moisture is hjecte into thetuhineforthe inposeofremovhgwater soiuble&positsfrom the tirrbineblades and aozzles.

Entrr ippedEwrgy- ' Ibe~ whichcemains in tk

FhibleShriPt-Ashaftwhichisintendedfmapera0ioa

Hydno --A test fm leairs and mtegrity 0 f thepn~-



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S T D m N E M A SM 23-ENGL 1991 W b 4 7 0 2 4 7 O524305 bLO

Laterpl C r i h l Speeds-ThespeedsatWhich the Tplitude of die iaterai vibration of a machine rotar due toshaft rotationI.eachtheir maximum due .Proximity Probe-A non-contacting device whiche iec r on idy measuresthe positionordisplacementmo-tion of an obsexve surfacerelativeto the probe position.PurgeA i r 4 method of seaihgin which air (or ineatgas) isbidinto the seal ar housing to maintain a slightpositivep.essrireandthuspreventtheentranceofcoaruuni-nants.ResiSEnace lkmperaure Detector (RTD)-A devicefor d g emperature in which the ewhicai resis-tanceof tbe&vice changeswith mperaiure.Respoase The-'ib time required to m v e r to thed y uue operatingvalue afterasudden changein bad.Service Factor-he factor by which the maximumpowercapabilityof a device exceeds its ratedm

SpeeiTied Conditions-Specified conditiolls are aUcustomer d e f d power, speed and steam conditions atwhich the turbine must operate.Steam liirbine-A prime mover which converts thethermal energy of steam directly intomechanical energyof d o n .StiffShaft-A shaft which will not be operatedduringn o d ircumstancesatspeeds reater hanthenrst areracriticalspeed.Therm0coupl-A &vice for Sensing temperatures inwhich a pair of di ssi ml ar conductors are pined at twopints so that an electromotive force is developed bythermoeiectric effects when the junctions are at merenttemperature. NEMAStandard130-91.



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SM23-1991Page3Section 2CONSTRUCTION

21 TYPES OF STEAM TURBINES2.1.1 clsssifiedby Exhaust conditkns2.1.1 .I NO"DPISING TURBINEA noncondengng turbine isa steam urbi nedesigned toaperatewith an exhauststeam pressureequal tourgreatextbanatmospkricpressure. NEMA- 11-13-1969.21.12 CONDENSINGTURBINEA m - turbine is a sream Wine designed tooperatewithanexhauststeampressurebelowamia6p~cP=-=2 1 2 CWslfedbyNunberofStegesand

NEMAStandard1-30-91.Clwvahrea

2.1 2.1 SINGLEVALVE -LE STAGE TURBINEA s ingie valve single stage turbine is a steam airbinewhich hasonegovmor conmiled valve and one stage.2.12.2 SINGLEVALVEMULTISTAGEURBINEA single valve multistage turbine is a steam trirbinewhich has onegovmorconaouedvalveand woormorestagts,2.1 9.3 MULTIVALVEINGLESTAGE TURBINEA m d t i d v e Agie stage turbine, is a steam turbinewbichhas two orm a tgovernorcontmkdvaivesandonestage.

NEMA- 6-21-1979.

NEMASEendard 6-21-1979.

NEMA spnd id6-211979.2.19.4 YULTIVALVEuLTWTAOE TURBPIEAmuitivaivemuitistageturbineisasteamuxbinewhichhas two ar more governarCaimlled valves and wo OT-stages-

215 C ~ b y P F o c e s S N e e b sNEMAStandard6-21-1979.

2.13.1 m D A WWA C ) EXTRACTIONTURBINEA controlled (automatic) extraction turbine is a steamturbmewhich has an opening(s) in the turbme casingfortheextractionof steam and whichisprovided with meansfar directly reguiacing the flow of steam to the turbinestages followingtheextractionopening for thepurpose ofmmiiingextractionpressure. NEMAStandaid 6-21-1979.

2.13.2 N O " T R 0 U D EXTRACTlN TURBYSEA nonconmiied exnaction turbine is a steam trrranCwhich has an opening(s) in the turbi ne casing for thcextraction of steam but which does not have means facantrolling thepresswe of the extracted steam.NEMA SIPndard6-21-1979.2.1.3.3 NO" TR0LLED IN TuRBWEA I1oI1contTdledmduction turbine is a steam Mbinewhichhas an opening(s) in theai rbi necasingfainductioaof steam but which does not have means for CQltlDUiiliethe pressureof the inductedsteam.NEMA S W d d 11-14-1W.2.16 4 m D NWCTION mPRESSURE)mBWE

A controlled induction (mixed pressiire) turbine is asteam turbine which is povided with sepirate inlccs farsteam at two pressures and has an automatic device f aconb.olling theflow of steam to he turbinestages follow-ing he inductionopening.2.1.3.5 INDUCTIONEXTRACT" TURBINE

An induction exmtion Mbi nc isone which combincsthe fatum of extraction (controlled ar nanconmikd)with thefeaturesof induction.2.2 STEAM TURBINE COMPNENTS

NEMA stendprd6-21-1979.

NEMA tanderd6-21-19B.

2 2 1 nirblnecaslngA turine casing is the enc lom which sumomis tbc

rotating elementof the turbine and supports hes t a t i msteamparts.CasingsshallbeaxiallysplitJadiauysplifaa combination thereof.he turbine casing W be divideaintotwourmonsectionsas follows: N E M A Standard6-21-19B.2.2.1.1 STEAM INLR ENDSECTIONwhichcontains he higherpressuresteam.2.2.1.2 EXHAUSTENDSECTIONThe exhaust end section is that partion of the cssingwhich contains the exhaust connection and the steam atexhaustconditions. t shaalso contain the low pressnnstage(s) of a multistage turbine.

The team inletend section is thatportionof the riffpinnNEMAStandard6-21-197W.

NEMA Standard6-12-1979.



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SM 23-1991page4

2.2.8.1.1 A p t s u r e impulse urRateau stage coLIsi8t8dsmionmy expnshx~nozze(s) and one row of rotatiagbkides.2.2.8.1.2 A velocity-compoanded impuise or Curtisstageconsistsofstationaryexpansionnozzle(s)Imdtwoamore rows of rotatingblades.2.2.8.13 A v e l o c i t y ~ p u n i d e d i m p u i s e ~ ~ s i a g eumsists of Srationary expansion nozzie(s), am?IOW atrotatiogbladesandoneormorereversingchambas.TbepressmdropacrossaRateanstageisreiativelybwinwmpoaisontothepssmdmpacmsaCmtis~.Authorized E n g W n g t l h n a h -21-1070.2.2.8.2 R ~ C T I O NTAGEA reaction stage consists of stationary expanSionnozzie(s)discharginghighvelocitysteamjetsaitherotat-ingblades.Apressuredropoccursinboththesiatioaaryand otatingelements.229 shaftseals2.28.1 CASING SHAFTSEALSCasingshaftsealsminimizetheleakageofsteamoutofuie casingdong tbe shaft.rheentnuiceofairinto he casingdongtheShaR yareaaraaged fur the admifipimi of steam at a canstant low

NEMAStandard-21-107B.

For condensing turbines, seals are arranged to jxemtpressmcand ow mperalme

NEMAStandard6-21-1979.INTERSTAQESHAFT SEALS

Interstage shaft seals minimize the leakage of steamh g he haftbetweenstagesm amuitisfagem r b hNEMAStandaid 6-21-1979.2.2.10 Beerlngtlouslng

Abearing housing Coataias andsupputsabeariagfs)andisequippedwithseaistopreventlccageofdaodttieentninceofm o h , ust,and foreign matmi&.NEMA- 6-21-1970.2.2.11 mtln(Y2.2.11.1 RADIALBURINOSRaclialbearingsarebearingsW h i c h s u p p a r t t b e ~elementinhorimtalshaftbirbines.Iheyareofihtsl~~,tilting pordmantifrictiontype. In verticat tmbrnes, hesebearingstnri sllv positiOn themtar assembly.NEMAStandrurl6-21-1970.2.2.11 9 T H R W BEARINGSThrust bearings rn m g s hich trammitthe axidthrust of the rotatlligdement to the beaping bousmg andmaintain the axial position of the mux assenibly m the



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casing. They m of the antifrictm, laad, ar scgmeniaitutuigpadtypt. NEMASWdaid 6-21-1939.2.2.113 ANTFRICTIONBURIN08Antiictim bearingsstmuidhavea minimumratinglifeof3 earsa25 o0Ohoursw h e n a p e r a t e d ~ ~ a tmaxgnumtblUStdradis l loadsaodat~speed.Authorized Engheeiing Inkrmillion6-21-1979.The ating life is tbenumberof houisatcunstantspeedtbat9perctntofagroupofidcnticalbearhgswiiiopcratcbefcxe the fitaevie-nce of fatigue devebps.kthomed E n g i i n g nbnnaakn6-21-1979.2.2.12 RotorA88etnbly

"be r ~o tssembly is therotlltingelemntof the urbinewhichinclubesaipartsattachedtotheshaft,excludiugthcca ip l i n g S ) unlesscouplingis integralWitb the shaft.NEMA- 621-1979.2.2.13 W h 0 d s m )

wheelsared iscs which are nmgrai witb,orxcdto, the~ieshaftandoawhichbladesaremounted,orinwwhichbladesorbuclrmsaremachined. NEMA- 6-21-1979.

2.2.16 H a n d W 0 ( S )A hand vaive@) is the valve which sal ates steam flowto a gmup afnozzle(s)to pennit e&cient apetriton atredmtdpowerawithdualsteamconditionsHaudvalvalvescan be either manuaily c o n d i e d or arbomated and areused on singie valve turinesoniy.

2217 PmtecthreDeViceNEMASiaKliUd6-21-1979.

Apotective device is one which, alone oras p?* Qf asy9iem,respondsinsomepredetemiinedmannerto,~sor-malconditionsaoendlligtheopewtionofthe unitorsys-tem towhichit is connected. NEMA Standard6-21-1979.

SM 23-1991Page 52.2.18 ConadllngDeViceicaliy i ni ti ates action of a system which caaerols a MnB1apaationofthetiirame.2219 ExtemalcontrdDwlceAn extanal control devi is an element which is E-sponsive to signais other than turbine spaad, ie., flow,presswe, -,and soforth,dacis toconirolthef b w of steam to the turbiDe. u shalt be pnemwidmecban idy , hydraulically.or electricany actuated fiomthe signal sollfcc to position he governorvaive@). (Ref-m m Section 3.1.6.)

Acoatrolliagdevice isOM which manidlyNEMA- 11-13-1968.

NEMAStandard 6-21-19'19.2220 WamlngDeVlceA warning de* is one which,by visile or auiblcmeans, orboth, indicatesthat an abnomai apefatingum-ditionexiscs,2.2.21 SentlnelWamlngValveA sentiael waming valve is a pressure warning devicewhichopenswhaithesteampressurerisestoapredeter-mined1eveLThedeVicesha dischge totheatmosphereandshallbesolocatedasto be plainly visible&For condcaskig tl&K it shall be set at 5 psig 135kFa(gauge)]. For noocondensingmnes the minimmmaximnm exhaust steam pftssuR,Whicheveris greater.followingapplications:

NEMAStandard6-21-1879.

seing shall beeither10percentor 10psi (OLpa) boveA sentinciwarning vaive is not recoaimended for the

locatiais where the discbarge of steam to theam+sphaeisobjcctionable,hamdousorpmhibkdbyhw

NEMAstandard 6-21-1979.

a i n e swhich utmd volatile gase^Mbineswhicbareanangedforauiomaticworunat-

hir these applicaliom,an alteniate wanimg devicemded start-upoptionai rip deviceis iecommended.2.222 s o w w s )

Authorued Enginwing Information 1-91.

A soleplate(s) isa machined fiat steel piate(s) or cast-ing(~) or mounting of the equipment supports and farbiting and grouting to the foundatiar.2.223 mapiate

Abaseplate is a fabricated of cast continuws tructurehavingmachined pads for mountingof he equipmentandforbolting and groutingto the foundation.

NEMAStandard 11-13-1689.

NEMASQndard 11-13-lQ69.



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STD -NEMA Sf l 23-ENGL

2.3 FEATURESANDACCESSORIES

m 6470247 05243q 266

9. Insulation for the high tempemm section of thtWine to limit exposed siirfaoe temperatme to16pF(74OC) orother tempemture specified by theP10. S t e a m p r e s s w e g a u g e s to i n d i ~ in l e t s te a m , ~ring, nrststage,dexhauststenimpressure.11. Coupling between the turineand driven machine(normaiiy fumhhed by the m8nufacturea of thednvenequipment).12. coiipling guard SuppOIted f rw tbe baseglate ocadjacent bealing housmg(s). Tbe couplmg guardshouldbecasilyremovableandbe~ientlyrigidresuuofnamalt odilycaitsctbypersonnel.Wbcocont inuaus ly luba ica tedcouplragsare~ thecoupiing guard housing should be fitted so thatoi l leakswillbepmted.13. GlandleakageevacUatingappIiratus hendieglandcasngdesignrequiresitsuse.14. Tachometer of the vibaatuig mai, machanical,a re~type;iodicatiagspeedsfroniabovethcipspeed to M o w he minimum aperatiag speed. Th-chometers shall be suitale for the specifmed eavi-Ionment.15. S u p e m h r y instniments to monitor such as vibra-tion, axial shaft movement,tempemtms, etc.16. ShaftgroundingdevicetocarrytogromdanysaticromandwhichmayotherwisebuildtoLevelswhichddamageturbhcbearings.17. Rotor turning gear togeU er with driving maus,engagementand isengagement feaiures, and lubeoil pressure interlocks to permitslow urningof themtorsystemonstatt-upandsbutdown.trip valve which provides a means far8. AlbusSmquick and positive shutof of admjssion stcam f aemegencY tnppui g.19. Nonretuni valve(s) for blocking ihe revme flow ofs t e a m f k o m ~ i n t o t h e t u r b m e t h r o u g h ~orextractioaopenings.20. Redmiantoverspeedtrip.21. Exhaustreliefvalveornrptriredisctopre~overpiessrningof the exhaust end section (see Sectim8.7).22. Vacuumbreakertoadmitairiatotheexhau9tamnecti ons d a ondensing turbiue in cmk toreducecoastdowntime.

to withsiand deflection and plevent rubbing as a

charge which might be developed on the hirane

. .

Additbd items may be availsble.AuthorizedE n g i i t q ~nfamaiion1-12 s ControlledEXttadknandmledkrdudknmrblnes

Conwlle exmaion, ccmtrolled i ndocti on, and um-mlled induction exmction turb8nes &ail include basic



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features W i n tems 1 thrwgh6ofU.1, togetherWittithose lisied in 23.3.1 through 23.3.4.2.33.1 Controlled extraction turbhm shall bave apre+8utt regdath8SySteB formtroiiingmtp s s m of theextracted ste9m by regulaiing the fbw f steam to theturbinestages fallowing the extracth opening(s). Anon-return valve br the extraction apallng(s), which is alsoactpated by the ovaspetd t i p system. is nquind farinstallationintheexoactimsteamline(s).2.3.3.2 controlled mduction turbinesShan mve apes-me regdating sysrem for cantrollingtticpm5urcof theimjuc th steam toregulatet h e b w ofsteam tothe urbinestagesfoiowingthein&ctionopening.Atripvaivewbi&isalsoactuatedby theoverspeedmpsystemisnquiredfnrinstallaaonintheinductionsttamk.233.3 Dependmgon hesourceof inductionsteam, theusashould consider the need for a steam ssainer in t i i s

AumaiEed Engineering Infornietion 11-14-1985.2.3.3.4 Controlledextraction turbinesand controlledin-duction turbinesshall have a multivariablemiml systemuiatingsystemaadthespeedgovemingsystem.

chdethecombinationofthefcxegoingitems.

NEMA- 190-1991.

h e o protect the loweapressure stages of me urbine.

which provibes nterconnect i On diepressiutrCg-2.335 conaroued nductim~rtractioarabi nesshall in-

NEMA- 11-14-1085.23A ~ ~ E x t r a c t b n T i a M n e rNonccmmiiedextnictionturbinessballincludetbbascfeaaacsiistedinitemsl througIi60f2~.1,togctfrtr~ithmwisecmnvatve(s) farthe xtractionopening(s). ' he quan-tity and lomion of nomearni valvesare tobedetermhlb y t h e t r i r b i n c m a n ~ b a s e d o n e n t r a p p e d a i e r g y

~redimdaacypol icy . NEMAStandard 130-1991.2.3.5 N ~ l l e d k i $ u k n n i i b l I l @ S

NoaiconmIIed induction turbinesshainchide thebasicfeahaeslistBdinitnS1tl1rough6of23.1,togetheswirba trip vaive@)for he induction opening(s).NEMA- 11-14-1985.2.4 TURBINERATING2A.i PowerRated power is the maximum specifiedpower outputofthe~ine.Itismeasuredattheoutpitshaftofthearrbine.NEMA Standard6-21-1979.

SM23-1991page 7

242 speed2.4.2.1 RATED SPW

Ratcdspeedisthespeedcanesponduig toratedpowa.It is measiaed at the output shaft of the turbw, is ex-pressed in rievdutioas per minute, and is quai toM essthanm8ximm~ u o u speed.2.4.2.2 W u u Com~uousPEEDMaxmum conhinuous speed is the highest specifiadspeed at whicb a turbine can be operatcd continwuslypwidedproperovaspeed~goverwr- - a r ei astal l edand operatianal.2 ~ 3 omralPower,SpeedandSteamhJ- power,m and- ooditionsaretbostc a i d i t i o n s f w a d m d ~ a a d a t w b i c h r h e s t e a mratcwillbeguafan~U A S ~ C o n d i t l o n s

2.4.4.1 WNuW STW C t d mMinmum steam ~ t i ~ a r ehelowest inlet stcampressure and tempemm and lowestexhaustprcssm towhich theturbineissubjectedincontinuwSopaatiOa.

NEMA tandprd 6-21-1979.

NEMA- 621-1979.

corabns

NEMA- 6-21-1979.

NEMAstadard 6-21-1979.2.4.4.2 M A # ~ ~ ~ ~ T E A ~ ~ ~ N ~ T K I N ~Maximum steam CDnditiOIlsam thehighest inlet steampitssrrreand imperature and exhausspIesllm to W h i c bthe tiirbmeis subjectedincaltinuousopaation.NEMA- 621-1979.2.4.4.3 W u u u E N m v SmwM n i I n m ~ g e a m c o n d i t i . M l s i u e t b e ~ i n l t tsteam presswe and t e m m nd the highest CxImustpmsm at which the turbine is requucd to produ as p ec in ed p o w er~s p eed2.4.4.4 hLET STEAM PRESSREuiietsteampressiire s thepressureof thesteam suppliedt o t k tUrbii.Jtis mwredat the $tcf3minlet conncctimof the airbineand is e x m a s gauge piessure.NEMAStandard6-21-1979.2.4A.5 EXHAUST STEAM PRESSUREExhaust steam pressure is the pressure of the steamsystemtowhich the turbine exhausts. t ismeasuredat theexhaust connectionof the turbine and is expressed as agauge pressurefarn airbineSandasanab-solutepressrrre for condensing uhines.NEMAStandard6-21-1979.



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STD.NEMA S M 23-ENGL 1971 D b 4 7 0 2 4 7 0524311 9L4

2.4.4.6 ExtRAcT#))JSTEAM PRESSUREExtractionsteam pmsm is the pressine of the steamextractedfrom the urbine. it ismeasuredat theextractionwnnecticm of the turbine, and is expressedas a gaugeP===2.4.4.7 hwCnON STEAM PRESSURE

NEMA-6-21-1979.

Inductionsteam~isthepIessureofthesecoadarysteam supplied to theWine. t ismeasureattheinduc-tionconnectianof thetrirbineandisexpressedasagaugep rsiae.

2.4.4.8 INLET STEAM TEMPERATURENEMASEandaid 6-21-1979.

Inlet steam tempeniture is the total teIn- of thesteam supplied to the turbine. It is nreasiiredat thesteamin le tcmnec t ionof the tu rb ineandisex~ inde~Fatireobeit~indegrcesCeW.NEMAStandard 6-21-1979.2.4.4.9 EXHAUST STEAM TEMPERATUREluhapststeam emperameisthe totait e m m fthesteam cxhartpted from the ti nrbi ne. It is r n d t thecxhailst CoMectiOn of the tuxbine and is expresd mdegreesFahrenheitor in degreesCelsius.NEMAStanderd 6-21-1979.2.4.4.10 WRACl STEAM TEMPERATUREExaaction steam temperatureisthetotalteInperatureofthe steam extracte from the turbine. It ismeasuredat theexixmirn connection of the tintiineandis eJtpressedinegreesFahrenheitorm degreesCelsius.NEMASEendaid6-21-1979.244.11 1NDUCTK))II STEAMTENPERATUREUidu c t i o o s t e am t empen im r e i s t h e t o t a lm~o ft h e ~ s t e a l n ~ W t o t h e ~tislmasmtdatthe i i i ducti onconnectimof die urbineand isexpressedin de- Fahrenheitor in Celsius.NEMASEandaid-21-1979.

2.4.4.13 DUAL Srrrun CNMl SDual steam conditiansare wo ofmmcombin8tons ofiniet steam pressme, inlet steam tempenitine,or exhaust-pressure.2.4.4.14 VARIA l S IN STEAM CCXJITlONSThe Iatng,capability, steam flow, speed re andpressme control shall be basedonoperation at maximumstcamunutionsasdefinedm 2.4.42.SteamMbiaes shall be capable of operating under he


followingvariatioasininletpressureandm~butp e ? f ~ s h a l l n o t n e c e s s a r i ly bem accardance withthestandaadsestab~foroperatmgatmaximumsteamconditions.continuousopetatiaiatotherthanmaximumsteam conditioI1s sharequirereview by the turbiwman-ufacturer.2.4.4.14.1 VARUTKJNSFROU hhXUuU NLETSTEAM


PRESSUREThe urbine shalibe capableof operating without dam-ageat less than the guaranteedsteam flow tothe Mbinewith average Wet pressureof 105 percent of maximumidet steam pressure. (This pemisible variation recog-n i z e s t h e ~ i n p r e s s u r e w i t h ~ i n s t e a m f l O Wencountered n operahion.)The nlet steam pxsure shall average not more thanmaximumpressiireover any 12 month opedugperiod,

maximumpressurein maintainingtheseaverages,e;xceptTheinlttsteamprwsureshailnotexceed 10perccmd

during a b d OilClitioI1SDuring abmnmal cosiditim, the steam paessare at thetiirbineinletconnectionshallbepermitredtoexdmax-h u m pressure briefly by as much as 2pesent, butheaggre@e drnationof such swings beyond 1M percent ofmaximump s s u r e shallnotexceed12hwrsper 12mondioperatingpenod. NEMA- 6-21-19m.2.4.4.14.2 VARIATIONSFROU WXiNUM INLETSTHMm P E R A l U R ETheinietsteamtempeniturestaveragenotmorethan

maximum tempexatme over any 12month operatmgperiod.In maintaining this average, the tempemm shall notexceedmaximum tempemureby nme than 1f l ( 8oc )exceptduringabnnmalcoaditions.Duringabaonnalcoo-ditions,the tempcratiae shall not exceed maximum tern-peratureby m m ian m ( 1 4 O c ) fwojmathgperiods



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~- ~

S T D - N E M A SI 23-ENGL L77L H 6470247 0524312 850

SM 23-1991page9

h2-theenthalpyofsteamatwrhaustsLeampaeasiiredinitialenaopy.NEMA idard -21-197Q.2.5.1.2 AcniAL ST E M RA-26.1.2.1 TURBINE-TErbinesmunrateisthequaatityofrmctsteamnqairadby the l i rbi oeper miit ofpower outpit, lneasmdattbtouiputshaftofthe tmbme.Itisd y inpoundsofsteamperhorstpower-hour(orinkilogremsasteempa ilowatt-hour).2.51 -2.2 TURBINE GEAR TEAM WlEWhenagearisprovidedytheturbineman~, thtrequiredby the turbinegear set per unit of power outpiit,measured at the output shaft of the gear. It is &yturbine gear steam rate is the quantity of inlet weam



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S T D e N E M A S M 23-ENGL 3 9 9 3 M b 4 7 0 2 4 7 0524333 797

SM 23-1991Page 10eqxessed mpoundsofsteam pet harsepower-hour(or ink i l ~ 0 f s t e a m p e x k i l o w a # - h o u r .NEMAStendard-21-1979.2.5.1.3 GUARANTEED STEAM RATE'Theguarauteedsteam rate is thesteam ratewhich willnot be exceeded When the turbine isoperaredatw)rmalpower, speed. and steam condkions.2.6 TURM"CO"ECTK)NS

NEMAStenderd 6-21-1979.

u 1 o u t p u t s h a f f ~26.1.1 Omput shaft cxtensionS shall be Spatable for acyimdricalcouplingbore and provided with a keyway(&tapaed ooupling bom with a keyway(s), tapered for ahydraulic ft, ornttedwithan hie @coupling hub.2.6.12 When a tapered shaft extension wi th keyway(s)isspecied, he taper, wupiinghub, andmupiingnut shaareavailablefarshaflextenshs rw 2 inchesm 5 inches.

N E M A W 1-14-1985.

be inaccardancewirb Figure 2-1. NEMA aper diameteSSNEMA- 11-14-1985.

2.6.1.3 if cyhdrical shaft Cxtension is specfied, t isncommendedthat thecwpling-to-shaft it be an inmfer-ence fit NEMA- 11-14-1985.26.1.4 When a hydraulic fit coupling is specified, hemountiug method should be reviewed with the turbinelnallllfimmr.2.6.1.5 Recommended use of one and two keys andkeyways isas shown in Tbble 2-1.Authid Enginwring Intomiobon 11-14-1986.2&2 SteamComecUons

I i irbmeflangedsteam Conne c t i o n s shallbe facedanddrilled or bolting toflangeswhicharem accordancewithANSUASME B16.1 orB16.5.CastiNnlflaagecOM~nsshallbeflatfacedThe hi cknessof cast iron exhaust flanged connectionsunder 1 0 m c h e s ( 2 s o m m ) i n d ~ b e n o t l e s s m

Class25ofANSUASME B 6.1.Singie vaive single stage hariuwallYsplitcasingan-bines hallhave steamcannectionsm thebwexhaifdthetr nbi ae.connections formakingup topipenot0ver2inches indiametex (So m m nominal di amter shall have


intenial taper threads conforming to ANSI/ASMEB .20.1-1983. NEMAStandard11-14-1@8 5.26.3 ArorlllaryConneUtonsAuxil iarycotl I lect iomthataredireadedshallconf~toANSVASME B120.1-1983. W y , hese are a d ering prtssure gauge-, drain Co fatcasingandsteamchest,casingsealingglandsandbeariqgh ~ ~ , c o o l i n g ~ , v a l v e ~ l ~ ~ , a n d ~ f f o2.7 LUBRICATKIN2.7.1 NipressueTypekibrcation Singie2.7.1.1 OIL LUBRlCATESLEEVEBWNS

NEMA- 11-14-1086.

s t e ( l e W W )

ab.

C.

( t iomzomL~~meB)L U ~ ~ W O I Ihouldbe prendedby oill ~ilarmeans.Beatinghousings should be arge enough topeanitsolidsor water m d e o the bottarn and shouldhaw a dtai n connectionat the lowest point, oil fiilfittings, and an oil level indicam.. F ~ i l i h f o r c d i n ghouldbeprovided~hcnne^-essary to assure the proper oil temperahrre. niecooling water should be supplied at a temperamenot exceeding 90%(32Oc).

Sim-

2.7.1.2 GREASER OIL LLJBUCAEA N i F H C "BEAWNGSGmse-lubricated autifriction bearings should beregreaseable~IIiekid.Grease ittings should ex-tendtotheoutsideoftheniachiaetopermitregreas-ingduringopemion.Means should beprovided arventing grease lutNi-cated bearings to pment the buildup of pnssurewithin the housing.Facitiesforcoolingshouldbeprovidedwbennec-essary to assure the proper lubricant tempemme.Thecooling water shouidbe suppiiedat a tempera-turenot exceeding909: (32Oc).

27.2 PressumtLpeOil Lubrlcatii2.7.2.1 ~ O D U C T I NIt is recognized that there s awidevariationin turbineSzesandapplicaths which makes it impracticaitohaveone recommended ubrication systcm ckign. However,



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22/64

STD.NEMA SM 2 3 - E N G L 1991 H 6470247 0 5 2 4 3 1 4 623

the oilowingdiouidservewagenaal designguide totheo e a f u r ~ h i s r a q u i r e m e n t s .27292 OILPWPS272.2.1 A main oilpump drive^ from the turbine shaftara seperately driven pump to provi& oil for lubricationaadgovemingshouldbepm4de.d.272.2.2 Anauxiliaryoilpumpforuseduringthc tart-by bic design ? whan qecihd. niiS pump should bepowaedbyadiffemismceofeaagythanthemainoilpimp.AprrssurtsensingdeviceshouMbeprovidedfcxpmsmeintbcmainsystemdmpsbebwapredeterminedvalmFor a Mbinedriven uxili ry oil pump, the turbine8bOddd m o all of the@pli* pvisim ofdiesesltmd&L272.3 OILRESERVOIR

u p ? s h p t - Q w n p e M d s h w l d b e ~ w h e n r e q ~

aptomatically sfming the ruailiary oilpump when the oil

A samate ail ~ ~ S U V O ~ Thouldhaveaac.dt.f.

2.7204 oLcoolar(s)empuame oftbc oilsuppliedto thebcaringsatamaxi-mimi d 120F (49oc), with a maximum woling watertmrpaaaarcm x excealhg 90F 32OC). It shouldhave afwl ing fC~ofO.~ ln he wataside fopcoaliagtowelwater an afouling faaorasncommendcdby the manu-nicMafarothtrcoolingwate?sources.'Ibemo~sbouldbe suitable fora workingpressmeof notkss than 75 psig[517 kPa gauge)] m thew w ide.Singkartwin~kmmaybeused.Eechcoolershouldbe capable of operatioa at a pressure q u a i to or peat tertima the nlief valve setting of positive displacement oilpumpsor ofth maxllnum shutoff dischargepressiae ofca~trifugalil pumps.M coolets should be piped inparaciwith acontintmus low transfervalvetopert . , i hetraas6er ofoil from one cooler to he ocher without inter-rupting the oil flow. Each cooler should be sized for the

The oii coola hould be capable of ma imhhg the

SM 23-1991Page 11total cooling loadandshouidbearrangedandventedf?maintaining eitha cooler with theWire in ojmation.2.7.2.5 OIL FILTER(S)Single or twin oil tilters may be used. Afi l tafs) shoptdbe capable of nmving panicles arger than25 micmns.When the film is clean, the pmsurc drop sbould notexceed5 Pgi 35 kPa) tdesign t a n m a a d low.Tiviufltersshould be piped inparaiicl witha con- fkwtransfervalvetopermitthe transfa of oil fiom 011c filtat o t h e o c h a w i t b u t ~g the oi l flow. Each nUashould be sized fm the otal oil flow end sbaild bc U-ranged aad vented for lminmining uthu f i l tawirh tbetiirbineinoperation.Acommontrsasfavalvemaybt~fortheoilflteIsaQdcoolas.m?l~cartridgeshouldbecamsion nesisauu. Filter cases should be suitable foropaationatapressurenotlesstbanthcrei idvahn~oftbepmitivedispiacementoilpumpsoratthemaximumshutoff ischarge pressiireof cenhifugal oil pump.2.7.2.6 RPNAND INSTRWEWTAT2.7.2.6.1 Pressure sensitive devices sboahlbe prwidadforea&prtssurclevel(forwrampie,oii &tokarings,discharge 6rom oil pumps,befase and afta flta(s) andc ~ n h ~ lil). Means should be pwidad fm BII ai-lieem a i n ~ a s a p p r o p r i a i e .Authorired Engineering Inforniafionll-lClOBs.2.7.2.6.2 if bearing mctal thenwconplesot Il)s arcnot pvic, tben thamometers should be povidad forbe provi&dbefore and after oil d e r @ ) . Thermowel l sshould b e p v i d d in the piping f a h e m fthCr-m e t e r epiacemaitwhileoniine.TbenmweiasshoukibegaSfilledOrcrnrosion-resistantbimetalliCtypc.AuthorioedEngineeringIn- 11-14-1985.2.7.2.6.3 An oil sight flow indicatm wbui spccifiashouldbe p r o v id e d m the oil return from each caringhousing where thedesign permisA u t h o f b d Engineering Infotmatm 11-14-1985.2.7.2.6.4 A pressiireregulam or relief vaive should beprovidedtomaintain the oil pressure evel(s).2.7.2.6.5 Afterfabricafim,pipingshauldbecleaneddpassivated by mechanical an4or chemical means.Authomed EngVieering I n h i i o n 6-21-1879,2.8 PROVISIONSFOR THE ENVIRONhENT2.8.1 EncksureSteam turbines shoud pfembly be i nstal l ed in en-ciosedareas.Thee?Fe &tsofundseMceconditi~may

oilwtlet fromcachbesring housing.Tbemiametasmay

AuthonzedEng tnea r ing I~11-14-10Bti.



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SM23-1991Paga 12bemi@ted by the use of one or moxe of themeasmesbescribed in2.82 and2.83.Authobd Engineefing Infonnetkn 11-14-1985.2m E x p o r i u r e t o N a i f a l ~in general, d xposed surfaces should be potectedagainst usting by apaotectivecoatiagorpaintafter instal-hion of the unit. Enposed workiqg parts which affectaperationd heunt such asgovexnor, govexnor inkage,fuiuum pomts, Valve stems.and imilwelements shouldb e ~ a g a i a s t ~ g i s t u i g b yhe useofcomwion esis-tantmatenalS.Equipment having nonpressure lubricated bearingssbouldbedcsignedtopvcnthetnaruiceof *

dust,and fmign mamiaisto the governing s y xbearinghai9ngs.aning systans, r both, shouldbepruwtedasbilowxboth, should be protected againstthe entranceofwater orforeignmaterials by proper seaiing devices. Thepoints tosidarelements.Tbereservoirshouieprovi&xiwirhaventwithanairierandcarnectionstofacuitsteremovdof water.2.8.2.2 Inadditiontothe oregoingprotectivemeasum,trireswill be lessthan ?F (4%)

EqpipntnthaMig~l&iCaboihydrauEicgov-2.82.1 The ULni- system 09 goveanar system, 09

beprotectedinchideallcofinectuwisorapeningstotbeoilEaleVoir, goveznor. gBromotor, bearing housings, and

tbe ollowing shouldbe includedwhen ambientttmpezg-1.

2

3.

4.5.

Far use durhg down imes,drains sbaildvi&d wheewater cancolkctforalls team,d , andwaterlines, he turbme casingand steam chest, andthe oil aad water si& of the oil coolex. Pneumatic"blowdown- may benectssarym someiostances.Aheater for the ail mservoir.Ifaa electricheater isspecineditmustbeofawifncicntlylowwaadeasitytopmtcokingof lkoilAn uxili rypumpmaybe reqiiired to eosure oil CircUlatBon for uni tonnheating.An enclosure or bood witb venting to cover thegovemlg system may be provided, and heatingshouklbesuppliedtoprevent icing.The mountandtype of enclosureand heating wii i be governed bylocalconditions.Protection against fieeziag for instnuaenBandd P i @ &mine manufacturer shouid identay those l i nes~resuat-protectionoypa.asa.AuthobdEngineeMgInfomiehon 11-14-1985.

2..3 Exposu~toAb110mia lAtm0spher icoondltknsif possible, the turbine should be located away froin

damaging fuma nd vapars, or abrasive, magnetic aimetallic dust. If this is not pnictical, the atmosphericcandirioasshouldbe called to the aaention of themanu-factufft. Suitablematerialsor protective coatingsmay berequiredtoansetthecomisiveeffectsofthefumes.Whennecessary purge air connections on bearing housings,glaad cases nd govemmshould be provided.Auth ired EnQnWring Infonnaoion11-14-1s.2.9 GENERALREQUIREMENTS2.9.1 PmssureanTemperaaireRanges

Sieam turbinesshouid be designed andproportioned aroperationatmaximumsteamconditions.Genedpressnreand tempexatme ranges utsown in Figure 2-2. Theranges are general, accmding to tempeam&xsurecambinationsat which pomt materialordesign changes,OrbOth,~~berequired.Authorlled Engineering nformation6-21-1978.2.9.2 VlbratlonThe vibmion of the turbine rotar (double ampitude)within thespecifedoperating peedrangeasmeasuredonthesprfacedtheshaftadjacenttotheradialbeaaingsshallbe m accadancewith the foilowing:2.9.2.1 SINGLETAGE URBINESThe maximum permissiblew i o n habe not peatexthan2.0 mils for speeds 4ooo rpm and ower,or 1.5 milsfor speeds4001rpm and higher.NEMAStandard11-10-1985.2.9.2.2 MULTISTAGETRBINESThe maximum permissi'ble vibratian shall be inaccar-daace with Figure2-2. The absolute values for vibrathlevels above3ooo pm can be derived from the followingformule 1M

Shaft mechanid and e lec t r id runout sbaii be deter-mined by slow rolling the rotor in its bearings whilemeasming theNwut witb a proximityprobe. if it can bedemaisoatedthatmtcbanid&electncalnmoutis~-ent,thissha be added to the abwale vibration level optoamaximum25peacentof thedioweddoubleampiitudev i r25mils, whicheverisgreater.NEMAStendard6-21-1978.



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S T D - N E M A SM 23-ENGL 1771 6470247 05243Lb 4Tb

SM 23-1991Page 13not have the specified margins betweem the apaatingspeadsand~speeds.nthiscasetheturbinedesignashould Catculanerotor response to unbalance. Theprimecaisiderationisseasitivitytom~AuthoriredEnghming Inlonnation 6-21-1985.2.9.4 NAMEPUTEDATAtiabiaenameplale:1. Manufacainr'snameandbcatioa2 Sai a l numW3.-. Ratedborsepower5. Ratedspeed6. Maximuminletste9mpressure7. Maximmillletsteamtunpenitiite

8. Maximumexhauststeampressure9. M a M m u m e x ~ ~ p r t s s u r e ( i f ~blc)10. Tripspeed11. Maximum continuous peed (ifdifmnt fim ratedrg6ed).12 ml ataal crit ical speed13. purchaser'sequipmeat item number (when speci-fied).

nie following minimum data StlfJu be given on the




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STD-NEMA SM 23-ENGL 1993 m 6470247 0524337 332 m

L

f t+ '

I CIE



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ST D-NEMA SU 23-ENGL 1991 6470247 0524318 2 7 9

SM 23-1991Page 15

RPM. THOUSANDSFigure2-2MAXIMUM PERMISSIBLE SHAFT VIBRATION



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SM 23-1991Page 16Table2-1RECOMMENDEDKEY FITS

(up to & including) 1-502250335044505

550665077.508910

Twokeys may be used in any c89e.

4050657590100115125140150165180190rn230w

Table24GENERAL PRESSURE AND TEMPERATURE RANGES



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S T D I N E M A SU 2 3 - E N G L 199L b 4 7 0 2 4 7 0524320 9 2 7SM 23-1991Page 17

steam 0 cnm he turbine.niepilotvaivecoatroisbcflowof highpnssme fluid to thepower cylink. This flowdhighpressmfluidcausesthepistonmthepowcrcyindato move in rcspaise to the signai h m hegovanarconQo1mechasiism.81.6 Extemalcontrol-'deaibedbebw:3.1.6.1 SPEED CHANGER TYPE

NEMA- 612-1986.

Extanal calm1 devices shall be me of thne Eypcs

-mchangatypeis- dirtcts,iaDothegoverning system which in hun positions the g o m a rcoatrolled vaivt(s). The govenoat shall be Aaxcd toprovidethe9pecinedadjustaiespecrange.3.1.6.2 ReuOlESET Popsr TYPE?be remote set poiat type is mcorparated dinxtly miothegovanmgsystemwhichinmposi~tbegovamancudfd valvc S). Tbc gwawr shall be 8ekctcd toprovide the specincd adjustableranges faiwatroingpatameta93.14 3 ALVE ACTlJAlW TYPE

Tbe valveacluating typeissepame h n l tlegovan.'e extaaal signai acts to positiaa e i t k tbe gmaacrcoamiiedvalve@) or a separate liacmounted valve Inthiscase.tbe govemxactsoniy asa speehiting@ eemergeacy)goveniar.

3.1.7 speed changerNEMA- 11-14-1985.

Thespeedchanga isa device fwcbging the setting0 f th eg o v ern in g s y ~w i th in th e~ i f i ed s p eed ra n g ewhile the turbineisin aperation.3.2 SPEU GOVERNING SYSTEM

NEhkStrvidard 6-12-1885.

CLASSIFICATIONSpeedgoYeaningsystemSs h a l l b e c ~ a s s h o w n mTablt3-1. NEMA standatd 6-12-1985.



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STD.NEMA S N 23 -ENGL 3993 m b 4 7 0 2 4 7 0 5 2 4 3 2 4 8 6 3 mSM23-1991Page 18

TWb 3-1SPEED GOVERNING SYSTEMCLASSIFICATION

A 10 0.75 13*B 6 0.50 7*C 4 0.25 7*D 0.50 O Z 7*

~ ~~~~ ~~* niese Maximum speed Rise Percent values can beachievedunderthef~wi43conditians:a Govemor system isadjustedfopmaximum sensitiv-ity.b. Rotational inertia of the equipment is relativelyiargeforthepowerrating.c. Steammditionsproduce a relatively low theoreti-calsteamrate.Agowrnorsystem n seMcewhichmeetsali thefoliow-ingwnd.itionsshallbecapableofiimiingspeedtopreventoverspeed trip when load is suddedy reduced from rate

to zero:a nie driven machine is synchronous pe rator .b. Thegovernorsystemisoperatinginamodeinwhichit m s odemand for electricalpower.c. niesteamturbinehasaninletpressureofatleast150psig i1035kPa (gauge)].d. Tbsteamturbineexmuastoaccm&~.

-RangeSpeed ange, expressedas a percentageof rated speed,is the specined range of opeming speedsbeioworaboverated ,$xxd or both, for which the governor shall bed j d e henthe ucbh is Operatmgnnder thecontrolo f ~ ~ g o v e a n o r .3.22 8bximunSpeedRlseThe maxjrnum speed rise expressedasa percentage ofratedspeed,isthemaximummomentaryincxeaseinspeedwhich is obtainewhen the turb neis dcveiopmg ratedpower outputatnited speed and the bad is suddenly andunnpletelyreducedtozeao.

NEMAStanclard 6-12-1985.

Maximumspeed rise (%) =

1.

2.3.

when the steam mditiom (inlet inlettem and exhaust pressrire) 8Ic set at ratedvaluesandheidconstantWhen the speed changer is adjusted to give ratedspeed with ratedpowerOUlpULWhen any exteanaiconmldeviisrenderedinop-erative and blocked in the open positfon so as tooffexnoresaictionstothefreefiowof steam tothegoveanarcontrolledvalve(s).

-(SeeFigure3-1 oragraphicrepmentationof speed rise

charactexisticsof a ClassD ovenior.)32.3 speedvariationSpeed variaiion, expressed as a percentage of ratedspeed, is the totalmagnitude of speed change or fluctua-t i o n s h m he speed setting uner the steady state cadi-tiom given in 33.4. Lhe speed change is dehedas thedifem m speed variation between the governiag sys-

tem n Operationand he goveZnmg system biocked tobeinoperative,withalloiherconditionswnstant, jmdvari-&an includesdead bandandsustainedosciiiati~Speed variation (+a)

2xratedspeed(See Figure 3-2 or graphic npresenratiai of speedvariation charactaisticsof a ClassD overnor.)3.23 DEADBAND

Deadbandis thetotaimagnia>dtof hechange in steadystate speed withinwhich thereis no &ring measiirablechange in thepositionof the governorconmilexivaive@).It is a measureof the speed gweming system insensitivityand sexpressed in percent of xated speed9.232 SrMiUnSabiity is theability of the speedgoveming system toposition the goveniar conmlied valve@)so that a sus-tai nedosc i l ia th of sped or ofenezgy input tothe urbineisnotproducedbythespeedgovemingsystemchniagoperation under sustaid load demand or following achangeto a new sustainedloaddemand.324 Speed Regulation,steady StateSpeed regdation, expnxsed as a percentage of ratedspeed,is the change in gli5t8ined speed when thepoweroutput of the turbine is gradually changed fmn atedpower oulput to zen, power outpit mider the followingsteady state conditions:



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S T D - N E M A SI 23-ENGL L99L b 4 7 0 2 4 7 0524322 7 T T

SM 23-1991Page 19107%

100.0%

Owt

O

2 5 9

iII1IIJLOU) 100%

Figure3-1SPEU) RISE NEMACLASS D GOVERNOR

Figure3-2SPEED VARIATION NEMACLASSD GOVERNOR



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STD.NEMA SM 23-ENGL 1991 m b470247 0524323 636 =SM 23-1991Page20

P

IO 1oOYLOADflgure3-3 STEADY STATE SPEED REGULATION NEMACLASS D GOVERNOR3.3.5 PmssunChangerThepressurechangerisadevicebymeansofwichthesetting ofthepressure regdatingsystem maybe changedfor the piirposeof aajusting the p m s m of the exhauststaun or ofthe extraction or mduction steam whiie theturbme is m @on.3.3.6 SteaiyStatePressureRegulation


Far controlid extraction or conmiled i nduct i on typein sustained extraction or induction pressure when, withidenticalsettingsofal lparrsof thespeedgoverning systtmand of the presswereguiating system(s), theexmxtmn ai aduct i an flow is gradually changed from rated flow Iozero flow.Fornoncondensmgturbioesprovidedwithexhauscpres-sureregdatas,the steady s r a t e p r e s s u r e r e ~s thechangein sustained exhaustpmsurewhen. with identicalseings of ail parts of the speed govemiag system andthrough tbe acti on ofthe p r t s m r r e m , the powaoutputofthesteamtucbineispduayreduced6romratepower output to zero power outpit.

turbi nes, he steady stare ~ ~ g u l a t i O n i s t h e C h a n g e




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S T D - N E M A SM 23-ENGL 1991 b 4 7 0 2 4 7 0524324 5 7 2 M

3.3.6.1 PRESSURE REGULA^i acreaseswith decrease n steani flow.3.3.7 Stablltty

Stabiity is the capabiiity of the pessure regulatingsystem(s) to position the pressurt controlledvaIve(s) sothat sustainedoscillationsof the coaadledpressrno(s) artheeaxzgy~puttothesteamturbincarenotproducedbythe pressrireregulatingSY-m drnmg m m ndfxmstaimfiowdemands or fauowing achange to anothervalue of sustained flow dtmand.For Ihe pirpose of this standad ~ ~ i l . l a t i ~~ b Y ~ p r e s s u r e r e g u l a t i a g s y s t e n i O f -pressurtarof encrgy i n p t are definedas the dinaenceb c t w c c n t h o s e e ~ w i t h t h e p r e s 9 u r e r e ~ s y s t e minsemicc and hme existing with thepressrinregularingsystem blockedor inaperstve.338 Pressum~rolperformaneeA ClassD oveniOringsystem (see 3.2) shall exhibit thefollowing characteristics when u t i h n a com-conml system:w . 1 changeinsuseainedspeedshallbe196maximumforany sustamed change in flowwithin limitsof 5%and95% f maximum inductionorexmuion bw guaranteedforthatload.

Rcssueregulation scoasideredpositivewhcnprtssureNEMASEandard6-12-1985.

NEW-6-12-1985.

NEMA- 11-14-1985.3.3.8.2 Steady state plessare regdation shall be 0.5 psi(35 pa) maximmor496 of ratedexbaust,extrauion.nwhichever is larger.indmion plesule wtpressed m psig oc kPa (absolue);N E W S U d d 11-14-1985.3.3.8.3 sustained 0Scillat.i~ f canttolled pressure,wiien aprat ing at C O I I S E B ~ ~low demaad op foiiowing achange to another canstantflow, Shan notcxcetdoa psi(1.7 kPa)ar2 of thecon~fledpnsnireexptssednpsiob kPa absolute); whichever is larger.334.4 s ~ o s c i l l a t i ~ o f e i a e r g y i n p u ~ w h e n o p

NEMA- 11-14-1985.

&gatconstant flow demand or foilowing achange toa n o r h e r ~ t f i o w , s h a U n o t e ~ 4 %fratedpcwer.338.5 The range of adjustment for ptsmre change(s)shapennit adjustment of exhaust, extraction or i aduc-tion pressure betweem f5 p i g (35kPa)M f10% of thecoamlled pressure expressed in psi or kFa (absolute);whichever is iarger. NEMA- 11-14-18 j.

SM 23-1991Page213.4 COMPENSATED CONTROLSYSTEM

Acompcrisatedcontralsystem isonewhich isprovidwith intaconneciions between its conml mechanismssothat the action dthe speed governar or of the pressureq d a t o r ( s ) also directly actuates the Othet control mech-ani sm3.5 ELEC K= GOVERNING SVSTEM3.5.1 BaslcFeatures

An electronicgovanhgsystemsha ncludethe foilow-ingbasiccompooeprs:1 Sensorswhichmeasureanoperat8igparamctaofthe turbineai system, andpoduceelectricsipah.2 Agovamx which compares- fnw ic sea-gor(s) witb theseiectcd setpoint(s) and padeces aQgnal(s)fobthevalveactuator(s)tomaintainsystem

Parametebs-3. An actuam@)whicb positionsthe valve(s) directlyor though a a m l nucbammi n I e s p s e t o hgov=SiEm.oneormonof followingparametersshallbecxxumlld

a. speedc. othersforspecificapplicatiom.

NEMASEandaid6-21-1979.

bythegovemingsystem:b. Each i n du c t i o n / e x a a c t i o n~

NEMASE8ndard 11-14-1985.332-a e p e n d i n g o n r a t i n g a o d ~u . 1 C O N T R O L P ~ E SAsignal selectmmay be incorporatedintbegOVUIIOrt0aowthegovenwrrtoreceivesignalsfromse.veralscnsusand tochoose the signal, which wiii result in thc piopavalveopening.Any paramm may be primary which the governingas constant during I K i TmB operation.y- -ny panunetex could be secondary which is i g n d slcQgasitisbelowthe preset value.3.599 CONTROLOF INDUCTIONOR E X T R A mThe governor may be designed o control the low pres-surevahrt(s) daninductim urextlxtionmine incon-junctian wih the high pressure n i v e ( ~ ) .n this case, hegovernar wnmls the flow tomaintain the steam pressureat each controlledextraction or induction opening whilesimuuaneously controlling speed when necessary for theappiication.

The following are accessories which may be selected,

. .



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S T D m N E M A SM 23-ENGL L991 6470247 0 5 2 4 3 2 5 409

Agoveniar with h i s capability incorporatesfeatUtestoadjust aii the ccmtroiied valves inmponse to a change inany controlledparameters. NEMAStandard 1-1-1991.

3.5.23 MISSHG SIGNAL DRECllONFEAtLIREniemissing signai &tecrion feature monitors all inputsignahandaetaminesifhey are in thecmectrange. Anysignai that is outof range shwld cause immediate actionby the electmiic govexnor to enSuresafe operationof thetmbine, nd shouldcausean alami indication.3.52.4 SENSOAREDUNDANCV8.5.2.5 OVU1SPEEDTmPvided in additiontotheprimary trip.nie overspeed rip feature in the governor can be pro-

3.5.26 other demonic governor accessories m a y beavailable.3.5.3 GENERAL

Cawshouidbe tal renin each installation to provide foradequate wiring. in addition, elecmnic governors and

INPUTS

theirassociafedWiringshouldbepro~fmnheat,weatand induced signais Local codesand area classif-shouldbe con-W h e n m i ~ b a s e d t u r b i n e c o n t r o l s y s t e m s I r r eprovided which interface with plant distributed controlsystems, there may be someoverlap of control loopsandconfusion egarding npuWoutputs.in hese casesthepnichaser and the vendor should mutually agree upon scaptand responsibility spiiL Extemal selpointscancome knnthe piant DCS but the turbine control loop should besuppiieby he Wine manufacturer.A typid eiec&onicgovernor schematic is shown mFigure 34.3.6 AUTOMATIC STARTCONTROLS

Automatic start controls are avaiiabie for turbine anddrivenmachine.nieWine manufacturer shouldtem -suited for recommendedequipment and pnicediiresAuaionred~neer ingInfonnabon6-12-1mS.


Figure3 4ELECTRONICGOVERNOR FOR PUMPOR COMPRESSOR CONTROL



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4 1 BASICFEATURESThefollowmgfeaturesandaccessoriesarenecessaryfartheproper functioning ofequipment and safety of opera-tion:11.1 Ananugill@device to cioseh i pvalveor hip and hrottic valve.Each turbi ne shall be pvided with amanual trippingNEMASEandard612-1985.4.12 ~ M p s y s t e mTheoverspeedtrip system shall besparkpioofandshallinclude the overspeed sensing&vice, linkage. and a (ripvalveora combined trip and bottle valve sepatate romthe spce governor conmiledvalve@).NEMA- 11-14-1985.A13 overspeedsensingDevlce

action to close the trip valve at a p m k a m m dspeed41A mspeedansing device is set

The ovaspeed smsing device mc1Udes those elementswhich are direcily responsive to speed and which initiateNEMA standard621-1979.

Tbt trip speed is the speed at which the overspeedNEMAStandard6-21-1979.

SM 23-1991Page23Section4PROTECTION

41.6 Comblnedmp and mmlemiveThecambineatrip,and hrott l evalve isseparatefmm thegovelnor controlled valve@)and is closed (tripped) mresponse to the action of the overspeed sensing &vicc,other safety &vices or manuai trip device. ?his vaivepennitsmanual ttirottling ofsteam tothe turbine.NEMAstandard6-21-1978.4.197 overspeed m h gThe np speedseauigsshowninTable4-1hallbeabovethe speedreacbeddueto themaximum speedrisecharac-Eeristic of the govetning system to avoid tripping theturbine on suddenlossof load.when design or application of driven equipment re-quires trip speedsotherthanthoseshowninThble4-1, the

NEMA Standd 6-12-1985.trip speed should be specified.Authohcl EngineeringInfomiation6-21-1979.

Table 4-1TRIPSPEEDSEmNGS

AB

115110C 110D 11041.5 TpVahre"be hip vaive is separate from the goveanor conmiied

vaive@)and sclosed(tripped) inresponseto heactionofUaiIripdeVice.theoverspbedscns ingdcvice ,o thasaf~&~orman- *An rluaueinpe


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~

S T D - N E M A S M 2 3 - E N G L 1991 W b 4 7 0 2 4 7 052 i1327 281

Sectlon 5FACTORY TESTINGS.1 TURBiNE 1. Qiecknerieraloperatioa6.1.1

1.

2

3.

~ ~ i e x b a u s t ~ ~ h s t e a r nor hydro testcd at a minimum of25 pi [172 kPa0 1 . NEMA- 11-14-1085.Wa exj&~ts, coils,or d e m hall be hyrottstedto1.5 times thespecifiedcooluigwar~,butnotkman115psip93kPa(gauge)].NEMA S k l d W d 6-21-1979.pressirre(s)shallbemaintained for a m f 15when no extemai l eaLs from be item under testareobserved,m i l l U t e S . T b e t e S t S h a l l b e a m s i d a e d ~

NEMA SEandard6-21-1879.5.12 No LondRunning Test

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S T D * N E M A S M 23-ENGL 199L 6470247 0524328 IL6 H

SM 23-1991Page 27Se d o n 6SOUND PRESSURE LEVELS

occurring atratedpowerandspeedandmaximumsteamamditions,are shownm ble6.1.TaMe 6-Sound PressureLevels

45-9090-1801-355355-710710-14001400-28002800-5600MoO-llu10OVeralldBA

63125250500lo002Ooo4OOo8Ooo...

989491898989898993

1069897929090909095

For arrbmemoimtedon asteeibasepiate.abdonea&ii-tioaaidecibeltotabul8tcdval~.Actnai swnd pre9sure evels may not equa maximumt a b w valm foral l fequewy bands. o v d BAis*therefore*ess than thesum of individual values.6.3 SOUNDPRESSURELEVUMEASUREMENT

Soundpresswe levels shallbe measiindin accordrmcewith Ameaican N a t i d Standard S5.1. Sec t ion 7.0,as tAcoilstical penamanCe is based on a sound prtssurel evel which is &pendent on acousticalc b & x i s t k s ofthe space m which the unit operam. AU m d oumilevels are assumed to be in k d s p k d netfleldarsemi-revaberant field which has r00m m t argeempgh so as to not significantiy ef?eztm ressumlevebathcmeasiiriagpoint.A s ix decibel drop off in SOWICI pressure levei per dis-tance douling in each octave band of inmesr, as themicrophoaeismoved~eachmeasurementlocationmaii direaionSamund he machine.regardlessof di stanCC,indcates approximate free fieid conditjolls.Correctionsmust be made f?environment whea the drop Onis lessthansudecibels.

Authorized Engiuieenng Infwmation&21-1979.PROCEDURE

i Japplicable,Eammamd asfallows:

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SM 23-1991page 28All 3Ound--readings shallbercaordedassoundpressmep s in decibels at refereace pressure of twot i mes 10' Newton per square meter.Ausoraid~readingsshallbemadewitbanoctavebaadmetersetforslow respanserecording isualaverage

minus 2dBAovetall shall bemurded.of maclings.F l d g m i s e le* equal to arhigkdian plus oc

' L b e ~ s h a l l b e p r o t t c t e d n o m e x t e r n a ld i s -tmbi ngmfluences(vibnitian,a i r cunen ts ,a l l de l ec~fmagnetic fi el ds which may affectreadings.Miaophoae locations shall be approximately,but notless than,aaemeter from any sound sotme being mea-d a n d a t a heigbt 1.5metersabove he fioor.Care hallbe talrcn toavoid a poBitiaiat the nodal point of standingwave. (hie set ofreadingsskould bed that is requaediftbemicrophoneissopos i t ioaed.~seotenceis~-izedEnghe&gWxmation.)ThcpaBitionofthemicmphanefmmeesirringkkgmundambientsound and otalswndshanbeidentical.4 CORRECTION FOR BACKGRWND NlSE

NEMASEendard6-21-1979.

rvm memats oftiirbiae sound plesSun levels shouldels. Levels at each iocatim should exceed backgroundle

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83449188 NEMA SM 23 1991 Steam Turbines for Mechanical Drive Service