US3566224A - Linear electromagnetic motor - Google Patents

Linear electromagnetic motor Download PDF

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Publication number
US3566224A
US3566224A US830564A US3566224DA US3566224A US 3566224 A US3566224 A US 3566224A US 830564 A US830564 A US 830564A US 3566224D A US3566224D A US 3566224DA US 3566224 A US3566224 A US 3566224A
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United States
Prior art keywords
electromagnets
projections
length
core
coils
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Expired - Lifetime
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US830564A
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English (en)
Inventor
Maurizio Vallauri
Luciano Parodi
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Fiat TTG SpA
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Fiat SpA
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Assigned to FIAT T.T.G. S.P.A. A JOINT STOCK COMPANY reassignment FIAT T.T.G. S.P.A. A JOINT STOCK COMPANY ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: FIAT S.P.A. AN ITALIAN JOINT STOCK COMPANY
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    • 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
    • H02K41/03—Synchronous motors; Motors moving step by step; Reluctance motors
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21C—NUCLEAR REACTORS
    • G21C7/00—Control of nuclear reaction
    • G21C7/06—Control of nuclear reaction by application of neutron-absorbing material, i.e. material with absorption cross-section very much in excess of reflection cross-section
    • G21C7/08—Control of nuclear reaction by application of neutron-absorbing material, i.e. material with absorption cross-section very much in excess of reflection cross-section by displacement of solid control elements, e.g. control rods
    • G21C7/12—Means for moving control elements to desired position
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E30/00—Energy generation of nuclear origin
    • Y02E30/30—Nuclear fission reactors

Definitions

  • a linear electromagnetic motor having a plurality of similar annular, coaxial and uniformly spaced coils or electromagnets, an elongated core of ferromagnetic material coaxially arranged with said coils, and a plurality of similar, annular projections, equally spaced along the core.
  • the length L of the coil row is related to the pitch of the coils P and to the pitch of the projections p by the following equations:
  • the length of the row of coils being greater than that of the row of projections.
  • the invention relates to vernier-type linear electromagnetic motors, which may be employed for example for remotely .controlling axial movements of members movable within sealed vessels, such as control rods of nuclear reactors.
  • the object of this invention is to provide an improved linear motor which is free of the above-mentioned prior art deficiency, and in accordance with this object, the motor includes a stationary portion having a supporting casing adapted to be tightly secured to the sealed vessel; a plurality of similar, selectively energizable electromagnets secured to the supporting casing, said electromagnets being equally spaced and extending along the axis of the casing so that the centers of the electromagnets are spaced by a constant pitch P; and a movable portion adapted to be connected to said driven member and having an elongated core of ferromagnetic material coaxially movable within the supporting casing, said core having a plurality of similar annular projections or teeth equally spaced so that the center of the annularprojections or teeth are spaced by a constant pitch p, wherein said projections and said electromagnets face each other over an axial section of the supporting casing along a length L, wherein
  • the weight of a short movable core provided with annular projections is lower than the weight of a long core, the useful lifting power and stroke length being the same.
  • the weight of the long core increases when longer strokes are required, whereas the weight of the short core provided with annular projections remains unaltered in accordance with the invention.
  • a motor having a short movable core provided with annular projections has a smaller length of the section L and requires less power with respect to the motors having a long movable core provided with annular projections, both during the operation and the rest condition, the lifting power and the outer diameter of their electromagnets being the same.
  • FIG. 2 is an enlarged sectional view on line Il-II of FIG. 1',
  • FIG. 3 is similar to FIG. 2 and shows an electromagnetic motor according to this invention
  • FIG. 4 is a diagram showing the switching cycle of the coils or electromagnets of the motor shown in FIG. 2;
  • FIG. 5 is a diagram showing the switching cycle of the coils or electromagnets of the motor shown in FIG. 3;
  • FIG. 6 is a perspective view of an embodiment of the switchover means adapted to realize the switching cycle shown in FIG. 4;
  • FIG. 7 is a perspective view of a modified form of the switchover means adapted to realize the switching cycle shown in FIG. 5.
  • 1 denotes a sealed vessel of a nuclearreactor provided with control rods (not shown), vertically movable in channels in the reactor core, in the vessel 1.
  • each control rod into and out of its channel is effected by means of a rod '2 remotely operated by means of an electromagnetic motor 3 comprising a stationary portion fixed to the vessel 1 and a movable portion fixed to the rod 2.
  • the stationary portion of the motor 3 comprises a vertical supporting casing 4 tightly secured to the vessel 1 by means of a sleeve 5 and a plurality of similar annular coils 'or electromagnets 6 coaxially secured to the outside of the casing 4.
  • the coils 6 are uniformly spaced along the axis of the casing 4 so that the centers of the coils are spaced by a constant pitch P.
  • the coils 6- are denoted in FIG. 2 by progressive Roman numerals, starting from the topmost coil which is denoted by I.
  • the movable portion of the motor comprises an elongated ferromagnetic core 7 coaxially movable within the supporting casing 4 and having a plurality of axially spaced similar annular projections or teeth 8, so that the centers of the projections are spaced by a constant pitch p.
  • the magnetic core 7 is secured to the end of the rod 2 to be operated by means of a coupling 9 of known type shown in FIG. I.
  • This coupling may take one of many known forms for interconnecting a driving and driven'mernber. For instance, it may be'a fixed connection or a connection of the Cardan type.
  • the part of the core. 7 provided with the projections 8 and the part of the stationary portion provided with the coils 6 face each other over an axial section of the casing 4 of a length L.
  • the length L equals 11 times the pitch p of the projections 8 and 12 times the pitch P of the coils 6.
  • the axial length of the part of the core 7 carrying the projections 8 is greater than the length L of the section over which this core portion and the part of the stationary portion carrying the coils 6 face each other. More specifically, the axial length of the part of the core carrying the projections equals the length L increased by the stroke length c of the movable portion with respect to the stationary portion.
  • n is the integer which is the number of projections 8 within the length L
  • the length L of the axial section of the casing 4 along which the part of the movable portion provided with the projections and the part of the stationary portion provided with the coils face each other is bound to the pitch p of the projections and the pitch P of the coils by the following relations:
  • n is an integer greater than 1.
  • the coils developing a maximum force are:
  • the magnetic force acting on the core 7 is nil with all configurations where the transverse plane extending through the center of any projections 8 coincides with a transverse plane extending through the center of a coil 6 or with the middle transverse plane between two consecutive coils; at the intermediate position: the force is small.
  • a number m of contiguous coils only should be energized among the n I coils.
  • the core moves to vary the magnetic resistance or reluctance of the magnetic circuit till the energized coils induce in the core a magnetic force which is equal and contrary to the load.
  • the core 7 takes a position such that the projections 8 occupy one of the symmetrical configurations with respect to the six energized contiguous coils, so that the total reluctance is lowest.
  • one of the said balanced configurations when the applied load is nil is the configuration wherein the coils I, II, III, X, XI and XII are energized.
  • the applied load equals-the maximum magnetic force which may be supplied by the coils to the core
  • the latter moves into a position in which the projections 8 on the core 7 assume with respect to the first energized coil and last nonenergized coil a symmetrical configuration, wherein the total reluctance is highest.
  • a balanced configuration with a downwardly applied load of a strength equaling the maximum magnetic force that can be supplied to the core is a configuration wherein'the coils I, II, III, IV, V, VI are energized, this configuration representing the condition under which the core is movable in a downward direction without being retained by the magnetic field.
  • balanced configuration is intermediate the two above described configurations.
  • balanced configurations in respect of certain increasing values of the applied load are the configurations wherein the coils XI, XII, I, II, III, IV or XII, I, II, III,.IV, V are energized.
  • the core moves by consecutive steps equaling in height L/(n l)n, the switching over in the proper sequence the direct current feeding the coils being accomplished by means of a switchover means of the typeshown in FIG. 6 and described below in detail.
  • FIG. 4 shows a switching diagram for the motor shown in FIGS. land 2.
  • the switching steps are given on the vertical axis of the ordinates and the coil order is given on the horizontal axis of the abscissae.
  • Each switching over moves the core 7 by one step; since the length of the core 7 equals the length L increased by the stroke length 0, the core moves over the whole stroke length c while it is in every position opposite the coils 6 over a length equaling L.
  • the core performs an upward movement over a length equal to L/ll X 12 and takes with respect to the energized coils XII, I, II, III, IV and V the same configuration it had before switching over with respect to the coils XI, XII, I, II, III, IV.
  • FIG. 3 is a detail view of an embodiment of the motor modified with respect to FIG. 2.
  • the modification comprises making the part of the core 7 carrying the projections 8 equal to L, while the part of the stationary portion carrying the coils 6 is made equal to L c.
  • FIG. 5 The diagram of the switching-over operations in respect of the motor shown in FIG. 3 is shown in FIG. 5 in which the switchover steps are given on the vertical axis of the ordinates and the coil order is given on the horizontal axis.
  • switching over should be effected in such manner as to energize in addition to coils I, ll, Ill, and IV also coil V and disenergize coil Xl.
  • the number of coils 6 facing over the axial section L of the casing 4 the projections 8 of the magnetic core 7, can equal n l, n being the number of projections within the length L, n being greater than 2.
  • the switchover device shown in FIG. 6 comprises a rotary motor 10, a set of earns 11 rigidly secured to the grooved shaft 12 of the motor 10, a plurality of switches 13 installed along a generatrix of the cams l 1 the stationary contacts of which are opened and closed by the action of the cams on the respective movable contacts.
  • the cams ll maintain closed during 180 and open during the following 180 the stationary contacts of the switch associated with each of the coils or electromagnets 6.
  • the rotation of the motor 10 and cams 11 effects switching of the current at the windings or electromagnets of the motor according to the H68. 1 and 2 and according to the switching cycle shown in FlG. 4.
  • the device shown in FIG. 7 comprises a rotary motor 14 rotating the grooved shaft 15, a stationary screw 16, a set of cams 17 fast with each other and splined on the side of the grooved shaft 15 and coupled by means of a nut and screw on the side of the screw 16, a plurality of switches 18 installed on a generatrix of the cams, stationary contacts of the said switches being opened and closed by the action of the cams 17 on the respective movable contacts.
  • the cams maintain closed over 180 and open during the following 180, the stationary contacts of the switches associated with each of the motor windings or electromagnets 6 of the motor shown in FIG. 3.
  • Rotation of the motor 14 effects through the splined coupling and nut and screw 16, the spiral movement of the set of cams 17 which are axially displaced on each turn by a pitch of the screw equivalent to the position occupied by one of the switches 18.
  • a linear electromagnetic motor for operating a driven member within a sealed vessel of the type including a stationary portion having a supporting casingadapted to be tightly secured to the sealed vessel and a plurality of similar, selectively energizable electromagnets secured to the supporting casing, said electromagnets being equally spaced and extending along the axis of the casing so that the centers of the electromagnets are spaced by a constant pitch P, and a movable portion adapted to be connected to said driven member and having an elongated core of ferromagnetic material coaxially movable within the supporting casing, said core having a plurality of similar annular projections equally spaced so that the centers of the annular projections are spaced by a constant pitch p, wherein said projections and said electromagnets face each other over an axial section of the supporting casing along a length L wherein the length L is related to the pitch p of the projections and to the pitch P of the electromagnets according to a predetermined vernier scale
  • said electromagnets extending over a length greater than the length L by an extent equaling the stroke over which the movable portion travels.
  • a means for simultaneously energizing m contiguous elecb.
  • c. means, after energization of an electromagnet k facing the last projection of said toothed portion, for either energizing the electromagnet which is successively arranged in the direction in which said switching operation occurs or energizing the electromagnet preceding electromagnet k by n 1 positions in said direction, whereby the energized electromagnets always face said toothed portion.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Plasma & Fusion (AREA)
  • General Engineering & Computer Science (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Combustion & Propulsion (AREA)
  • Electromagnetism (AREA)
  • Power Engineering (AREA)
  • Linear Motors (AREA)
US830564A 1964-10-09 1969-05-08 Linear electromagnetic motor Expired - Lifetime US3566224A (en)

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Application Number Priority Date Filing Date Title
IT2223564 1964-10-09

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US (1) US3566224A (enrdf_load_stackoverflow)
BE (1) BE670635A (enrdf_load_stackoverflow)
DE (1) DE1488500B2 (enrdf_load_stackoverflow)
FR (1) FR1455472A (enrdf_load_stackoverflow)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3851231A (en) * 1972-06-20 1974-11-26 Tracked Hovercraft Ltd Short stator induction motor
US3894275A (en) * 1973-12-11 1975-07-08 Quebec Centre Rech Ind Linear step motor
US4198582A (en) * 1977-06-24 1980-04-15 Exxon Research & Engineering Co. High performance stepper motor
US4215283A (en) * 1978-05-03 1980-07-29 Hinds Walter E Linear stepping motor
FR2466127A1 (fr) * 1979-09-18 1981-03-27 Commins Eric Moteur rotatif electro-mecanique
US4402386A (en) * 1980-09-30 1983-09-06 Otis Elevator Company Self-powered elevator using a linear electric motor as counterweight
US5480344A (en) * 1991-10-01 1996-01-02 The Furukawa Electric Co., Ltd. Polishing process for optical connector assembly with optical fiber and polishing apparatus
US9136749B1 (en) * 2012-09-28 2015-09-15 John M. Callier Elevator electrical power system
US20180019027A1 (en) * 2016-07-13 2018-01-18 Ge-Hitachi Nuclear Energy Americas Llc Moveable isolated rod couplings for use in a nuclear reactor control rod drive

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
LU71614A1 (enrdf_load_stackoverflow) * 1975-01-10 1976-11-11
GB1550367A (en) * 1975-07-05 1979-08-15 Lucas Industries Ltd Electromagnetic devices
US4423002A (en) 1979-12-19 1983-12-27 Framatome Apparatus for controlling a nuclear reactor by vertical displacement of a unit absorbing neutrons
FR2526241B1 (fr) * 1982-04-30 1986-04-04 Jeumont Schneider Moteur electrique a reluctance variable pour la translation des barres de commande dans un reacteur nucleaire
FR2509541B1 (fr) * 1981-07-08 1985-06-14 Jeumont Schneider Moteur electrique a reluctance variable pour la translation des barres de commande dans un reacteur nucleaire
DE3270973D1 (en) * 1981-07-08 1986-06-12 Jeumont Schneider Variable reluctance electric motor for the translatery movement of the control rods in a nuclear reactor
FR2730338A1 (fr) * 1995-02-03 1996-08-09 Commissariat Energie Atomique Dispositif electromagnetique pour le deplacement d'un ensemble absorbant de reacteur nucleaire
DE102011054727A1 (de) 2011-10-21 2013-04-25 Hochschule Offenburg Elektromotorischer Aktor, insbesondere für einen mobilen Roboter
RU2526053C2 (ru) * 2012-10-23 2014-08-20 Михаил Юрьевич Кудрявцев Линейный шаговый двигатель с продольным магнитным полем

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3851231A (en) * 1972-06-20 1974-11-26 Tracked Hovercraft Ltd Short stator induction motor
US3894275A (en) * 1973-12-11 1975-07-08 Quebec Centre Rech Ind Linear step motor
US4198582A (en) * 1977-06-24 1980-04-15 Exxon Research & Engineering Co. High performance stepper motor
US4288709A (en) * 1977-06-24 1981-09-08 Exxon Research & Engineering Co. High performance stepper motor
US4215283A (en) * 1978-05-03 1980-07-29 Hinds Walter E Linear stepping motor
FR2466127A1 (fr) * 1979-09-18 1981-03-27 Commins Eric Moteur rotatif electro-mecanique
US4402386A (en) * 1980-09-30 1983-09-06 Otis Elevator Company Self-powered elevator using a linear electric motor as counterweight
US5480344A (en) * 1991-10-01 1996-01-02 The Furukawa Electric Co., Ltd. Polishing process for optical connector assembly with optical fiber and polishing apparatus
US9136749B1 (en) * 2012-09-28 2015-09-15 John M. Callier Elevator electrical power system
US20180019027A1 (en) * 2016-07-13 2018-01-18 Ge-Hitachi Nuclear Energy Americas Llc Moveable isolated rod couplings for use in a nuclear reactor control rod drive
US20180019026A1 (en) * 2016-07-13 2018-01-18 Ge-Hitachi Nuclear Energy Americas Llc Stationary isolated rod couplings for use in a nuclear reactor control rod drive
JP2019534989A (ja) * 2016-07-13 2019-12-05 ジーイー−ヒタチ・ニュークリア・エナジー・アメリカズ・エルエルシーＧｅ−Ｈｉｔａｃｈｉ Ｎｕｃｌｅａｒ Ｅｎｅｒｇｙ Ａｍｅｒｉｃａｓ， Ｌｌｃ 原子炉制御棒駆動装置で使用するための固定した隔離された棒結合
US10872703B2 (en) * 2016-07-13 2020-12-22 Ge-Hitachi Nuclear Energy Americas Llc Moveable isolated rod couplings for use in a nuclear reactor control rod drive
US10872702B2 (en) * 2016-07-13 2020-12-22 Ge-Hitachi Nuclear Energy Americas Llc Stationary isolated rod couplings for use in a nuclear reactor control rod drive
US20210225533A1 (en) * 2016-07-13 2021-07-22 Ge-Hitachi Nuclear Energy Americas Llc Moveable isolated rod couplings for use in a nuclear reactor control rod drive
GB2567355B (en) * 2016-07-13 2022-01-05 Ge Hitachi Nuclear Energy Americas Llc Stationary isolated rod couplings for use in a nuclear reactor control rod drive
US20230120623A1 (en) * 2016-07-13 2023-04-20 Ge-Hitachi Nuclear Energy Americas Llc Stationary isolated rod couplings for use in a nuclear reactor control rod drive
US11721443B2 (en) * 2016-07-13 2023-08-08 Ge-Hitachi Nuclear Energy Americas Llc Stationary isolated rod couplings for use in a nuclear reactor control rod drive
US11728050B2 (en) * 2016-07-13 2023-08-15 Ge-Hitachi Nuclear Energy Americas Llc Methods of moving an induction coil to move a control element in a nuclear reactor

Also Published As

Publication number Publication date
DE1488500A1 (enrdf_load_stackoverflow) 1971-07-29
FR1455472A (fr) 1966-10-14
DE1488500B2 (de) 1971-07-29
BE670635A (enrdf_load_stackoverflow) 1966-01-31

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Owner name: FIAT T.T.G. S.P.A. VIA CUNEO 20, 10152 TORINO, ITA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:FIAT S.P.A. AN ITALIAN JOINT STOCK COMPANY;REEL/FRAME:004295/0360

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