WO1992005620A1 - Toles de stator de moteur a induction lineaire a dents coniques - Google Patents

Toles de stator de moteur a induction lineaire a dents coniques Download PDF

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Publication number
WO1992005620A1
WO1992005620A1 PCT/CA1991/000349 CA9100349W WO9205620A1 WO 1992005620 A1 WO1992005620 A1 WO 1992005620A1 CA 9100349 W CA9100349 W CA 9100349W WO 9205620 A1 WO9205620 A1 WO 9205620A1
Authority
WO
WIPO (PCT)
Prior art keywords
teeth
tooth
tip
primary
flanks
Prior art date
Application number
PCT/CA1991/000349
Other languages
English (en)
Inventor
William John Ballantyne
Laurence A. Pattison
Original Assignee
Utdc Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Utdc Inc. filed Critical Utdc Inc.
Publication of WO1992005620A1 publication Critical patent/WO1992005620A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K41/00—Propulsion systems in which a rigid body is moved along a path due to dynamo-electric interaction between the body and a magnetic field travelling along the path
    • H02K41/02—Linear motors; Sectional motors
    • H02K41/025—Asynchronous motors
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/12—Stationary parts of the magnetic circuit
    • H02K1/16—Stator cores with slots for windings
    • H02K1/165—Shape, form or location of the slots

Definitions

  • the present invention relates to linear induction motors.
  • Linear induction motors consist of a primary and a secondary.
  • the primary consists of a ferromagnetic body having teeth projecting to one or both sides. Coils are wound through the teeth to generate a magnetic flux path in the teeth.
  • the secondary is spaced from the primary by an air gap and acts to bridge magnetically the teeth of the primary so that a magnetic circuit can be established between selected pairs of teeth. Excitation of the coils generates a thrust between the primary and the secondary to cause relative movement therebetween.
  • the slots between teeth accomodate the coils that generate the magnetic flux in the teeth. From one aspect, it is desirable to have as large a slot as possible, i.e. the tooth spacing to be as great as possible, as this allows a larger cross-section of coil to generate the magnetic flux. The larger cross-section of coil reduces the resistance of the coil so that the losses are smaller and the linear induction motor runs cooler for a given current load. However, from a different aspect, it is also desirable to have the largest possible tooth-to-slot ratio so that the flux density in the tooth is lower for a given operating flux level. The saturation of the tooth is avoided and, for non-saturated operation, machine power factor and thrust per amp 2 factor are improved.
  • the purpose of the iron component in the induction motor secondary is to guide the magnetic flux across the air gap between the primary and the secondary.
  • Leakage flux performs no useful work but instead degrades machine performance.
  • the tendency for tooth tip leakage increases as the tip spacing approaches the value of the air gap.
  • typical maximum speeds range from 1 to 5 m/s. These speeds dictate a pole pitch of about 50mm - 60mm for a LIM powered by a commercial frequency (60 Hz) supply. It has been found that LIMs with a pole pitch of this order exhibit considerable fringing and tooth tip leakage, causing, among other things, a difference of about 50% in the flux entering the tooth root and that leaving the tooth tip. It should be recognized that the ability of the LIM stator to produce thrust is proportional to the square of the airgap flux density and reduction in flux across the air gap significantly affects the thrust produced. Attempts to increase the flux density are inhibited by the material characteristics and by the need to dissipate the heat produced by coils that generate the flux.
  • a primary of a linear induction motor comprising a plurality of teeth disposed in spaced relationship along a ferromagnetic body, each of said teeth having flanks extending outwardly from a root adjacent said body to a tip remote from said body, opposite flanks of adjacent teeth defining a slot to receive a run of an electrical coil wound about said teeth to generate a magnetic flux in said teeth, the flanks of each tooth progressively converging in a direction toward said tip so that said teeth taper progressively from said root to said tip.
  • a linear induction motor 10 comprises a primary 12 and a secondary 14.
  • Primary 12 includes a ferromagnetic body 16 extending along the length of the motor with a plurality of teeth 18 projecting from the body 16 in spaced relationship.
  • Each of the teeth 18 includes a pair of flanks 20 that extend from a root at the body 16 as indicated by 22 to a tip 24 remote from the body 12.
  • the flanks 20 converge progressively toward the tip so that the cross-sectional area of the tooth 18 decreases as the distance from the body 16 increases.
  • flanks 20 flare outwardly at the extremity of the tooth 18 to provide a local enlargement 26.
  • Opposed flanks adjacent teeth 18 define slots 28 which ac ⁇ omodate runs of electrical coils 32,34 which loop between selected slots 28 spaced apart along the motor 10.
  • the winding of coils to produce the desired effect with different power supplies is well known in the art and so will not be described further.
  • Each of the coils 32,34 includes a plurality of conductors which carry current supplied from a motor power supply (not shown) .
  • the progressively tapering slot facilitates the use of "mush” windings, i.e. bundles of random wound copper wire which are of lower cost than the ordered large section windings conventionally used.
  • Coils 32,34 are retained within the slots 28 by means of coil wedges 35 which co-operate with the flared surfaces of the local enlargement 26 to retain the coils and resist movement thereof out of the slot 28.
  • Enlargement 26 also smooths the iron/air flux transition at the tooth tip.
  • the secondary 14 is separated from the primary by an air gap 36.
  • Secondary 15 has an iron backing 40 to carry magnetic flux and an aluminum cap 38 to carry induced electrical currents. Again, the construction of the secondary is relatively conventional and well known in the linear induction motor art.
  • the tooth 18 tapers progressively so that in most applications the cross-sectional area at the tip 24 is between 40% and 80% of the cross-sectional area of the tooth at the root 22.
  • the tip area is between 40% and 60% of the root area.
  • the tip area is 50% of the root area.
  • the local enlargement 26 is ignored and the intersection between the projection of the flank 20 and the end face of the tooth 18 is considered the cross-sectional area of the tooth at the tip.
  • the length of the tooth will typically range from 40 mm to 150 mm and the included angle between tooth flanks will be less than 60 ⁇ more typically less than 40° and preferably less than 10. A range of 4° to 10° is preferred for most normal applications.
  • the primary had a tooth pitch of 19mm, a root width of 12mm, a tip width excluding the enlargement of 6mm and a tooth length of 45mm.
  • the enlargement projected 2mm to either side of the adjacent flank to provide a spacing between adjacent teeth of 9mm.
  • the flux density in the tooth was between 1.2 and 1.6 Tesla and the pole pitch was 57mm (3 phase supply) .
  • the tooth may be designed so that the flux density at the tip 24 is substantially identical to the flux density at the root 22 so that, compared with a rectangular tooth configuration as is conventional in the art, a greater spacing between the flanks of adjacent teeth can be obtained adjacent the tip 24.
  • This allows an increased cross-sectional area for the coil 32 to be utilized or, for a given slot area, allows the tips 24 to be spaced further apart than would otherwise occur with a rectangular slot.
  • the increased space in between tips is beneficial to ensure that magnetic flux does not simply migrate from tip to tip but does in fact cross the gap 36 into the secondary. For this reason, it is preferred that the spacing between adjacent tips is greater than the predefined gap 36 for which the motor is designed.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Electromagnetism (AREA)
  • Linear Motors (AREA)
  • Iron Core Of Rotating Electric Machines (AREA)

Abstract

Un primaire (12) de moteur à induction linéaire comprend des dents (18) définissant des fentes (28) destinées à loger les bobines génératrices de flux (32,34). Les dents se rétrécissent (18) de la base (22) au sommet (24). Ceci permet d'obtenir une surface de fente agrandie pour loger des enroulements de cuivre de section transversale plus large et pour réduire ainsi les pertes dans la machine, alors que la dent conique (18) permet d'obtenir une densité approximativement uniforme de flux, ayant une valeur caractéristique à travers ladite dent (18).
PCT/CA1991/000349 1990-09-26 1991-09-26 Toles de stator de moteur a induction lineaire a dents coniques WO1992005620A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CA 2026297 CA2026297A1 (fr) 1990-09-26 1990-09-26 Lames a bout biseaute pour stator de moteur lineaire a induction
CA2,026,297 1990-09-26

Publications (1)

Publication Number Publication Date
WO1992005620A1 true WO1992005620A1 (fr) 1992-04-02

Family

ID=4146055

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CA1991/000349 WO1992005620A1 (fr) 1990-09-26 1991-09-26 Toles de stator de moteur a induction lineaire a dents coniques

Country Status (4)

Country Link
JP (1) JPH04133655A (fr)
AU (1) AU8617991A (fr)
CA (1) CA2026297A1 (fr)
WO (1) WO1992005620A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1672773A2 (fr) * 2004-12-14 2006-06-21 Gisulfo Baccini Moteur linéaire

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2144441A1 (de) * 1971-09-04 1973-03-08 Siemens Ag Staender fuer elektrische linear- bzw. sektormaschinen
GB1375965A (en) * 1972-06-07 1974-12-04 Nat Res Dev Linear motors
DE2920478A1 (de) * 1979-05-21 1980-12-04 Kabel Metallwerke Ghh Vorgefertigte dreiphasige wechselstromwicklung fuer einen linearmotor

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2144441A1 (de) * 1971-09-04 1973-03-08 Siemens Ag Staender fuer elektrische linear- bzw. sektormaschinen
GB1375965A (en) * 1972-06-07 1974-12-04 Nat Res Dev Linear motors
DE2920478A1 (de) * 1979-05-21 1980-12-04 Kabel Metallwerke Ghh Vorgefertigte dreiphasige wechselstromwicklung fuer einen linearmotor

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN, Vol. 10, No. 221, (E-424)[2277], 2 August 1986; & JP,A,61 058 452, (FANUC), 26 March 1986. *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1672773A2 (fr) * 2004-12-14 2006-06-21 Gisulfo Baccini Moteur linéaire
EP1672773A3 (fr) * 2004-12-14 2006-11-29 Gisulfo Baccini Moteur linéaire

Also Published As

Publication number Publication date
CA2026297A1 (fr) 1992-03-27
AU8617991A (en) 1992-04-15
JPH04133655A (ja) 1992-05-07

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