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NEMA Standards Publication No. SM 23-1991 (R1997, R2002) Steam Turbines for Mechanical Drive Service Published by: National Electrical Manufacturers Association 1300 North 17th Street, Suite 1847 Rosslyn, VA 22209 O Copyright 2002 by the National Electrical Manufacturers Association. All rights including translation into other languages, reserved under the Universal Copyright Convention, the Berne Convention for the Protection of Literary and Artistic Works, and the international and Pan American Copyright Conventions. NOTICE AND DISCLAIMER The information in this publication was considered technically sound by the consensus of persons engaged in the development and approval of the document at the time it was developed, Consensus does not necessarily mean that there is unanimous agreement among every person participating in the development of this document. The National Electrical Manufacturers Association (NEMA) standards and guideline publications, of which the document contained herein is one, are developed through a voluntary consensus standards development process. This process brings together volunteers and/or seeks out the views of persons who have an interest in the topic covered by this publication. While NEMA administers the process and establishes rules to promote fairness in the development of consensus, it does not write the document and it does not independently test, evaluate, or verify the accuracy or completeness of any information or the soundness of any judgments contained in its standards and guideline publications. NEMA disclaims liability for any personal injury, property, or other damages of any nature whatsoever, whether special, indirect, consequential, or compensatory, directly or indirectly resulting from the publication, use of, application, or reliance on this document. NEMA disclaims and makes no guaranty or warranty, express or implied, as to the accuracy or completeness of any information published herein, and disclaims and makes no warranty that 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 or seller’s products or services by virtue of this standard or guide. In publishing and making this document available, NEMA is not undertaking to render professional or other services for or on behalf of any person or entity, nor is NEMA undertaking to perform any duty owed by any person or entity to someone else. Anyone using this document should rely on his or her own independent judgment or, as appropriate, seek the advice of a competent professional in determining the exercise of reasonable care in any given circumstances. Information and other standards on the topic covered by this publication may be available from other sources, which the user may wish to consult for additional views or information not covered by this publication. O NEMA has no power, nor does it undertake to police or enforce compliance with the contents of this document. NEMA does not certify, test, or inspect products, designs, or installations for safety or health purposes. Any certification or other statement of compliance with any health or safety-related information in this document shall not be attributable to NEMA and is solely the responsibility of the certifier or maker of the statement. ~ ~ . . STQ-NEMA SM 23-ENGL 1991 6470247 0524297 714 m TABLE OF CONTENTS FOREwom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RefaencedSEancbrrds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Definithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . sectm2 CONSTRUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ' I ) p e s o f S t e a m T . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CiassiñedbyExhaustcaiditiasis .............................. . N- Tiabmc .................................. CoadensingTUrbinc ................................... classified by Number of Stages and Coam1 Valves .................... SingleValveSingieSEagC'Iirrbint ............................ Single Vaive Muuistege Mine ............................. Multi* sil@ stage mine ............................ Muitivaive Muitisiage'ïixòine ............................. C i a s s i ñ d b y ~ N e e d s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . controlled (Alumtic) Exeraction Turbine ....................... NoncwtrolletiExtractiosi nlrbhw ............................ CmmUed InQiCtim (Mixdnesslire) M e ..................... InductimExtractionTirrbine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SteamIIiabinecctUl~ts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Turbinecasmg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SteamInletEndseCtion ................................. ExhaustEI?dstction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Irlemedia& sactiw ................................... SteamRing ......................................... StatiomyReveEngBladcs ................................ Diciphragm ......................................... sw. nlrbirbe ........................................ ImpuIseStage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . shaftseals ......................................... casingshaftseals ..................................... Intemagestlaftseals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bearings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ThnistBearings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . AntitÌiCtianBearings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RotorAssembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . wheels@iscs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Shroud . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . COnmhgDevi~ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ExtemalcontrolDevice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WamingDeVice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REFERENCED STANDARDS AND DEPlNlïïONS .................... Sectkn 1 Noacontrolled Induction 'linbine ............................ Steam Chest (GOV~IIKN vahe Body) ............................ Nozzles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . StationaryRevczsingCham~ .............................. ReactianS tage ...................................... BearingHousing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RacüaiBcarings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Biades(Buckets) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Handvalve@) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RotectiveDevice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PiSc i ii 1 1 1 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 5 5 5 5 5 5 5 5 5 5 5 plr sectlocr2 Sentinel W h g Valve ................................... 5 soleplate(s) .......................................... 5 Basephte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 FeatmsandAccessan ?es ................................... 6 BasicFeaMesaQd- ............................... 6 OptiOnalFeaMesandAccessorics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 c o n t r o n e d ~ ~ a n d c o n t r o l l e d ~ ?Itrrbines . . . . . . . . . . . . . . . . . 7 Ncmwntroiled Exüacîh Turbhes ............................. 7 Nonconp.olled Inductiai Ilabines ............................. 7 ?IiirbineRating ......................................... 7 power ............................................ 7 speed ............................................ 7 Ratedspeed ....................................... 7 Maximum continwus speed .............................. 7 N d Power end Speed and Steam Caiditions ..................... 7 Stcamconditiaas: ...................................... 7 MinimwnSteam(hKiibS ............................... 7 MaximumStcamconditions .............................. 7 MinimumEnergystcamccmditions .......................... 7 Inlets teampressure ................................... 7 ExhaiistSteampressUre ................................. 8 Extraction Steam Rressiire ................................ 8 Induction Steam Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Inlet Steam Tempemure .................................. 8 ExhaustSteamT~ perame ............................... 8 Extiaction SteamTemperatrae .............................. 8 Lndpctim Steam Tempgatme .............................. 8 Maximum Mowable Working Pressures and Teanptmtms . . . . . . . . . . . . . . 8 DualSteamconditions ................................. 8 VauiationsinSteamconditions ............................. 8 Flow Limits for an Automatic Exaaction ? M i h e . . . . . . . . . . . . . . . . . . . 9 HowrjmitpforanInductionTurbine .......................... 9 Units of Measurement for Absolute and Gauge Pressure . . . . . . . . . . . . 9 Thermodynamic?Iienns .................................... 9 SteamRateS ......................................... 9 I TheOretidSteamRate ................................. 9 ActualsteamRates ................................... 10 GuaranteedSteamRate ................................. 10 ?Iiirbineconnectiais ...................................... 10 outputshaftExte~ .................................. 10 S t e a m c o h u s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 AuxiliaryconnectionS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 LlbiClUb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 NonpFessure?lSpeLubncation (Single stage lbbines) . . . . . . . . . . . . . . . . . . 10 oil Lulnicztred sleeve Beanngs (HarizwEal Tiirbines) . . . . . . . . . . . . . . . . . 10 G?ease or oillubricatad Antiniction Bearings ..................... 10 p r e s s u r e ? l s l p e o i l L u ~ ............................... 11 InProduction ....................................... 11 Oilnrmpr ........................................ 11 oilReservoir ....................................... 11 oilcooler ........................................ 11 OilFdt~zs ......................................... 11 . . STD-NEMA SM 23-ENGL L99L b470247 0524299 597 = section2 piping and Instnunentation ............................... nwisons for the Esrvin>nment ................................ Eaclosufe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Exposwe to Nanrral Elements ............................... Exposure to Abnonnal Ahnœphedic conditioas ...................... GeneraiRequiremeats ..................................... PltsSureandTempemmRanges ............................. vi’bration .......................................... Singlestageïùrbim .................................. M d t i s t a g e ï ù r b ~ ................................... clitwspeeds. L ................................... NameplateData ....................................... Sedkn 3 CONTROLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GoveaningSystem ....................................... SpeedGOm ar ....................................... GOvmorconmlled WVe(S) ............................... Servomom System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Speedcbangetlype ................................... speedchanger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Speed Govaning System classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . SpeedRange . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Maximums @Rise .................................... speedvariation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DeadBand ........................................ stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Speed Regulation. Steady State .............................. steamPressurecaritrd .................................... PressureRegUlatingSysíea~ ................................ PressureRegUlatw . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Control MechaniSn ..................................... nessUre Controlled Wves ................................. pressurechanger ...................................... SteadyStatePxess~mRe guûuion .............................. PressureReguiatioai C. ............................ stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . pressure control perfamilmce ............................... Compensated coatrol System ................................. Electronic Governing System ................................. Basic Features ........................................ Accessones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Control Primiries ..................................... Control of inâuctim or Extracoon ............................ 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 .................................. RemoteSetPoint Qpe .................................. Valve Actuating- .................................. . 11 12 12 12 12 12 12 12 12 12 13 13 17 17 17 17 17 17 17 17 17 17 17 17 17 18 18 18 18 18 18 ZQ m m 20 20 20 A) 21 21 21 21 21 21 21 21 22 22 22 22 22 m STD.NEMA Sf l 23-ENGL 1991 m b470247 0524300 039 s e c t h 4 PRûïECTiON ......................................... BasicFeaûues ......................................... UanUalTrip ......................................... Overspeed'LtipSystem ................................... OverspeedScnsingD ................................. n i p s peed .......................................... nipvalve .......................................... Combined 'Ltip and Ihrottlt Valve ............................. overspeednipsystemsetting ............................... secSIon5 FACIDRYTESTING ..................................... 'Iiirbine ............................................. HydroTd .......................................... NoLoadRUnmngTesc ................................... Sectbn6 SOUNDPñESSUREJEVELS ................................ Gtaeral . ............................................ swnd€3essweLev& ..................................... soSmd~LevelMtasuremcntprocedme ........................ Camction for BacLgrwnd Noise ............................... souadResolution ....................................... Instnuneats ........................................... S d A ü e n d o n ....................................... sectm7 PRapARATI0NFORS"TANDSTORAGE .................... S h i j l p i D g R e ~ ...................................... Shipneat ............................................ W i t and Storage of Equipmeat .............................. sectkn8 INSTALLAIION ....................................... In-tion ........................................... SupervisionOfIaseallation ................................... steam Inlet and Exhaust Piping ............................... C i e a m n g o f ~ S t e a m P i p i n g ............................. SteamPipingS ystems ..................................... I n e t i o n ......................................... The Piping noblem as Applied to ?brbines Fbms Due to Stearn Pressure ............................... Fbms Due to Temperatwe .................................. Farces Due to Dead Weight ................................. AuowaMe Fœces and Moments on Sttam Turbines .................... DrainPiping .......................................... IÆak-ofli ........................................... Fuil-FiowReii &Device .................................... CoUptingAlignmcnt ...................................... Grwting ............................................ FlushingûiiSystem ...................................... In-tim .......................................... ........................................... Fouudation ......................................... ........................ ............................ seCtrOn9 OPERATONANDMAINTENANCE operatioa ............................................ Noncondensin ' g 'hbine opetatian of aMultisrage condensia . g'Ihrbine 'I)pical SEertmg Seqaence fima Steam nirbine ........................ Maintlmance .......................................... Intluduction ......................................... . . . . . . . . . . p.pc 23 23 23 23 23 23 23 23 23 25 25 25 25 27 n 27 27 28 28 28 29 31 31 31 31 33 33 33 33 33 33 34 36 36 36 36 38 40 41 42 42 42 44 44 44 51 51 51 51 51 51 51 STDmNEUA SU 23-ENGL 1991 6470247 0524303 T75 pige SeCtknS UitemalWaterWashing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 steamhinty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 Sacth10 INQUIRYGUIDE.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 STD*NEMA SU 23-ENGL L99L 9 6470247 052430il 7 D l W Foreword Ilhis standard has been developed by the Steam "wbiine Section of NEMA. In its preparation andrevision, considaation bas been given to the work of other organizations. such as the American National Standards institute, the American Peuoleum institute, the American Boiler Manufacturas Association, and the Amencan . SoCiety of Mechanical Engineers, striving toward the deveiopment ofstandards,anddtishaebygiventoaii whosesiandardsmayhavebeenh~~inthepreparatian of this publication. nK purpose of this standard f a singie stage and multistage mechanid drive steam turbines is to faciiitate the appiication of the.se turbines by engineers, users, aad conuactas, to promote ecwomieS m driving rotalhg mechanical equipment, and to assist in the proper seiection and app~ofthedifferingmechantcal designs of turbines. NEMA Standards P u b l i a SM 23-1991 revises and SupeISedes the NEMA Standards Publi- Cation Steam Turbines for Me~hanical z)rive S e M e , SM 23-1985. User needs have been considertd throughout the develop