Dahlander pole changing motor

Robert Dahlander

A Dahlander motor (also known as a pole changing motor, dual- or two speed-motor) is a type of multispeed three-phase induction motor, in which the speed of the motor is varied by altering the number of poles; this is achieved by altering the wiring connections inside the motor. The motor may have fixed or variable torque depending on the stator winding. It is named after its inventor Robert Dahlander (1870–1935).[1][2]

Invention

Robert Dahlander, a Swedish engineer working for ASEA,[3] discovered that switching the poles in a motor led to a reduction in the speed of the motor. In 1897 he invented an electrical configuration to switch between poles in a motor for which he was granted a patent along with his co-worker Karl Arvid Lindström. The new connection was named the "Dahlander connection" and a motor having such a configuration is commonly referred to as a "pole changing motor" or a "Dahlander motor".[4][5]

Operation

Dahlander motor wiring for low speed (delta connection) and high speed (double star connection)

The Dahlander motor is based on a 'consequent pole' connection. The primary factor in determining the speed of an induction motor is the number of poles, given by the formula

(RPM)

where

= Synchronous speed, in revolutions per minute
= AC power frequency
= Number of poles per phase winding[6]

A regular induction motor has an equal number of opposite poles; that is, at any instant, there are an equal number of North and South magnetic poles. Some smaller induction motors are connected so that all the poles are identical, causing the motor to act as though there is an equal number of opposite poles in between.

A Dahlander motor achieves different speeds by switching the configuration of the electrical windings, indirectly adding or removing poles and thus varying the rotor speed. The poles can be varied at a ratio of 1:2 and thus the speed can be varied at 2:1.[7][8][9] Normally, the electrical configuration of windings is varied from a delta connection (Δ) to a double star connection (YY) configuration in order to change the speed of the motor for constant torque applications, such as the hoists in cranes.[7][8][9] Star connections (Y) varied to double star connections (YY) are used for quadratic torque applications, such as pumps.[7][9]

Advantages and disadvantages

Dahlander motors have advantages compared to other speed control systems like variable frequency drives, as there is less power loss. This is because most of the power is used to drive the motor and no electrical pulse switching is done. The system is much simpler and easier to use compared to other speed control methods available. However, the Dahlander motor has the disadvantage of fast mechanical wear and tear due to changing speeds in such a drastic ratio; this type of connection also produces high harmonic distortion during the shifting of poles as the angular distance between the power generated increases as the poles are decreased in the motor.[9]

Application

Pole changing motors are normally used in applications where two speed controls are necessary. Some typical applications are:[10][11]

  • Pumps, wherein two speeds can be used to control the output flow
  • Fans, to get variable air flow output
  • Crushers
  • Milling applications
  • Cranes, where two speeds can be used in hoisting applications: one speed for material movement and the other for positioning the material held in the hoist

See also

References

  1. ^ US 725415 
  2. ^ Heilbronner, Friedrich; Jäger, Kurt (2010). Lexikon der Elektrotechniker (in German) (2 ed.). Germany: VDE-Verlag. p. 93. ISBN 978-3-8007-2903-6.
  3. ^ "Robert Dahlander". Dictionary of Swedish National Biography (in Swedish). Riksarkivet (National Archives of Sweden. Retrieved 12 December 2014.
  4. ^ US 725415 , CH 14112 
  5. ^ DE 98417 Arrangement for obtaining two different pole numbers for asynchronous AC motors, 11 February 1897
  6. ^ Eitel, Elisabeth (1 April 2012). "The difference between AC induction, permanent magnet, and servomotor technologies". Machine Design. Retrieved 21 June 2015.
  7. ^ a b c Boy, Günter; Flachmann, Horst (1983). Die Meisterprüfung Elektrische Maschinen und Steuerungstechnik (in German) (4 ed.). Wurzburg, Germany: Vogel-Verlag. p. 25. ISBN 3-8023-0725-9.
  8. ^ a b Jufer, Marcel (2013). Electric Drive: Design Methodology. John Wiley & Sons. p. 48. ISBN 978-1118621592.
  9. ^ a b c d Toliyat, Hamid A.; Kliman, Gerald B., eds. (2004). Handbook of Electric Motors (2nd ed.). CRC Press. pp. 234–236. ISBN 1420030388.
  10. ^ Deshpande, M.V (2010). Design And Testing Of Electrical Machines (1 ed.). India: PHI learning pvt ltd. p. 434. ISBN 978-81-203-3645-2.
  11. ^ "Dahlander motor". Archived from the original on 28 April 2015. Retrieved 9 December 2014.

Read other articles:

Kepulauan GrenadineGeografiLokasiKaribiaKepulauanAntillen KecilJumlah pulau32Pulau besarCarriacou, Young Island, Bequia, Mustique, Canouan, Union Island, Mayreau, Petit St Vincent, and Pulau Palm.Luas86 km2PemerintahanNegara Saint Vincent dan GrenadineNegara GrenadaInfo lainnyaGrenadineJulukan: GrenadinePopulasi • Totalperk. 20.880 • Kepadatan194,2/km2 (5,030/sq mi) Grenadine adalah sebuah kelompok pulau-pulau kecil yang terletak di garis antar...

 

Front Nasional Islam Bersatu untuk Keselamatan AfghanistanBendera dikibarkan oleh Front Islam BersatuPemimpinBurhanuddin Rabbani (pemimpin figur)Abdul Ali Mazari Sayed Hussain AnwariAsif MohseniAbdullah AbdullahAhmad Shah MassoudHaji Abdul QadeerMuhammad MohaqiqKarim KhaliliWaktu operasiSeptember 1996 – Desember 2001 16 Agustus 2021 – sekarang (sebagai Perlawanan Kedua)MarkasTaloqan, Afganistan (sampai September 2000)[1]Fayzabad, Afgaanistan (2000-November 2001)[2]Baz...

 

ماراكايبو سميت باسم بحيرة ماراكايبو  تاريخ التأسيس 8 سبتمبر 1529  تقسيم إداري البلد فنزويلا  [1][2] عاصمة لـ زوليا  التقسيم الأعلى زوليا  خصائص جغرافية إحداثيات 10°38′00″N 71°38′00″W / 10.633333333333°N 71.633333333333°W / 10.633333333333; -71.633333333333  المساحة 1393 كيلومتر ...

American politician For other people named Steven Pierce, see Steven Pierce (disambiguation). This article is about the Arizona politician and former member of the Arizona House of Representatives. For the New Mexico politician and former member of the U.S. House of Representatives, see Steve Pearce. Steve PierceMember of the Arizona House of Representativesfrom the 1st districtIn officeApril 3, 2019 – January 11, 2021Preceded byDavid StringerSucceeded byQuang NguyenMem...

 

أسبيستوخوري   تقسيم إداري البلد اليونان  [1] خصائص جغرافية إحداثيات 40°38′30″N 23°01′30″E / 40.6417°N 23.025°E / 40.6417; 23.025   الارتفاع 358 متر  السكان التعداد السكاني 6453 (resident population of Greece) (2021)4821 (resident population of Greece) (2001)3359 (resident population of Greece) (1991)6392 (resident population of Greece) (2011)...

 

Israëlau Concours Eurovision 2019 Données clés Pays  Israël Chanson Home Interprète Kobi Marimi Sélection nationale Radiodiffuseur KAN Type de sélection HaKokhav HaBa L'Eurovizion 2019 (artiste)Sélection interne (chanson) Date 12 février 2019 (artiste) Concours Eurovision de la chanson 2019 Position en demi-finale Qualifié d'office en tant que pays hôte Position en finale 23e (35 points) 2018 2020 modifier Israël est l'un des quarante et un pays participants du Concours Euro...

Broadcast Music, Inc.Tanggal pendirian1939TipeNirlabaFokusIndustri MusikLokasiNew York City, Amerika SerikatWilayah layanan Seluruh duniaProdukMusikMetodeLisensiTokoh pentingMichael O'Neill (Presiden & CEO)[1]Situs webbmi.com Broadcast Music, Inc. (BMI) adalah salah satu dari lima Performing Rights Organization (PRO) Amerika Serikat, bersama dengan ASCAP, SESAC, Global Music Rights, & Pro Music Rights. Organisasi tersebut mengumpulkan bayaran lisensi atas perantara para penuli...

 

For other uses, see Days of Our Lives (disambiguation). This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.Find sources: Days of Our Livez – news · newspapers · books · scholar · JSTOR (May 2008) (Learn how and when to remove this message) 1996 single by Bone Thugs-n-HarmonyDays of Our LivezSingle by Bone Thugs-n-Harmonyfrom...

 

52nd season in franchise history 2012 Minnesota Vikings seasonOwnerZygi WilfHead coachLeslie FrazierHome fieldMall of America Field at Hubert H. Humphrey MetrodomeResultsRecord10–6Division place2nd NFC NorthPlayoff finishLost Wild Card Playoffs(at Packers) 10–24Pro Bowlers 7 RB Adrian PetersonFB Jerome FeltonDE Jared Allen (bench)K Blair WalshLB Chad Greenway (replacement)TE Kyle Rudolph (replacement)OT Matt Kalil (replacement) AP All-Pros 4 RB Adrian Peterson (1st team)FB Jerome Fel...

Two pulsars orbiting each other Artist's impression of a binary pulsar A binary pulsar is a pulsar with a binary companion, often a white dwarf or neutron star. (In at least one case, the double pulsar PSR J0737-3039, the companion neutron star is another pulsar as well.) Binary pulsars are one of the few objects which allow physicists to test general relativity because of the strong gravitational fields in their vicinities. Although the binary companion to the pulsar is usually difficult or ...

 

Long-endurance unmanned aerial vehicle Heron IAI Heron 1 UAV in flight Role Unmanned surveillance and reconnaissance aerial vehicleType of aircraft National origin Israel Manufacturer Israel Aerospace Industries First flight 1994 Introduction 2005 Status Active, in production Primary users Israeli Defence ForceIndian Air Force Brazilian Federal Police Turkish Air Force Variants EADS Harfang IAI Eitan Avionics Services Caçador IAI Heron on display at the Paris Air Show 2009 IAI Super Her...

 

Austrian politician (1846–1909) HochgeborenKasimir Felix Graf BadeniMinister-President of AustriaIn office30 September 1895 – 28 November 1897MonarchFranz Joseph IPreceded byErich Graf von KielmanseggSucceeded byPaul Gautsch Freiherr von Frankenthurn Personal detailsBorn(1846-10-14)14 October 1846Surochów, Galicia, Austrian EmpireDied9 July 1909(1909-07-09) (aged 62)Krasne, Galicia, Austria-Hungary Count Kasimir Felix Badeni (German: Kasimir Felix Graf von Badeni, Polish: K...

16°36′10″S 59°38′26″E / 16.60278°S 59.64056°E / -16.60278; 59.64056 Map delineating The Saint Brandon Marine Protected Area (Cargados Carajos) by the World Bank in 1998 Avocaré Island (Avoquer, Avocaire, L'Avocaire) is an island located in the St Brandon archipelago.[1] In the World Bank Report recommending the creation of the marine protected area of St. Brandon, Avocaré Island was classified as a Group 3 Island together with Île Raphael, L'Île...

 

Questa voce sull'argomento cestisti statunitensi è solo un abbozzo. Contribuisci a migliorarla secondo le convenzioni di Wikipedia. Segui i suggerimenti del progetto di riferimento. Steve HamerNazionalità Stati Uniti Altezza213 cm Peso111 kg Pallacanestro RuoloCentro Termine carriera1997 CarrieraGiovanili Middleton High School1992-1996 Tenn. Volunteers Squadre di club 1996-1997 Boston Celtics35 Il simbolo → indica un trasferimento in prestito.   Modifica dati su ...

 

Chigozie UdojiNazionalità Nigeria Bulgaria (dal 2007) Altezza172 cm Peso67 kg Calcio RuoloCentrocampista Squadra svincolato CarrieraGiovanili Bridge Boys[1] Squadre di club1 2004-2007 Vihren Sandanski? (?)2007-2009 CSKA Sofia? (?)2009-2011 Asteras Tripolīs49 (5)2011-2012 Astra Ploiești8 (0)2012 Brașov6 (0)2012-2013 Platanias17 (4)2013 Atromītos16 (2)2013-2014 Arīs Salonicco13 (5)2014-2015 Dinamo Minsk45 (18)2016 Q. Zhon...

Storm Tornado outbreak of December 23–25, 2015GOES 13 satellite image of thunderstorms across the Eastern United States on December 23 TypeTornado outbreakExtratropical cycloneDurationDecember 23, 2015 (2015-12-23) – December 25, 2015 (2015-12-25) Highest winds170 mph (270 km/h) (Holly Springs, Mississippi EF4 tornado) on December 2390–100 mph (140–160 km/h) near Black Gnat, Kentucky on December 23 Tornadoesconfirmed38Max. ra...

 

Cet article est une ébauche concernant une intercommunalité française et l’Ain. Vous pouvez partager vos connaissances en l’améliorant (comment ?) ; pour plus d’indications, visitez le Projet des intercommunalités françaises. Carte des EPCI de l'Ain depuis le 1er janvier 2019. Depuis le 1er janvier 2019, le département de l'Ain est couvert par 17 établissements publics de coopération intercommunale : cinq communautés d'agglomération (dont une ayant son siège ...

 

God with us, slogan used by Germans Kaiserstandarte (Emperor's standard) of 1871 Gott mit uns ('God [is] with us') is a phrase commonly used in heraldry in Prussia (from 1701) and later by the German military during the periods spanning the German Empire (1871–1918), Weimar Republic (1918–1933), and Nazi Germany (1933–1945). It was also commonly used by Sweden in most of its wars and especially as a battle cry during the Thirty Years' War. Origins Matthew 1:23 refers to the prophecy wri...

Pre-Socratic Greek philosopher (c.490–c.420 BC) For other uses, see Protagoras (disambiguation).Not to be confused with Pythagoras.ProtagorasProtagoras by Jusepe de Ribera, 1637Bornc. 490 BCAbderaDiedc. 420 BC (aged c. 70)EraPre-Socratic philosophyRegionWestern philosophySchoolSophismMain interestsLanguage, semantics, relativism, rhetoric, agnosticism, ethics Protagoras (/prəʊˈtæɡəˌræs/; Greek: Πρωταγόρας; c. 490 BC – c. 420 BC)[1] wa...

 

Census-designated place in Tennessee, United StatesHelenwood, TennesseeCensus-designated placeLocation of Helenwood, TennesseeCoordinates: 36°25′24″N 84°32′29″W / 36.42333°N 84.54139°W / 36.42333; -84.54139CountryUnited StatesStateTennesseeCountyScottArea[1] • Total2.01 sq mi (5.20 km2) • Land2.01 sq mi (5.20 km2) • Water0.00 sq mi (0.00 km2)Elevation[2]1,388&#...