US3572290A - Apparatus for insulating slots in stators and rotors of electrical rotary machines - Google Patents

Apparatus for insulating slots in stators and rotors of electrical rotary machines Download PDF

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Publication number
US3572290A
US3572290A US696855A US3572290DA US3572290A US 3572290 A US3572290 A US 3572290A US 696855 A US696855 A US 696855A US 3572290D A US3572290D A US 3572290DA US 3572290 A US3572290 A US 3572290A
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Prior art keywords
chamber
particles
slots
core
insulating
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Expired - Lifetime
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US696855A
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English (en)
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Erik Frede Christiansen
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Danfoss AS
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Danfoss AS
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K15/00—Processes or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines
    • H02K15/12—Impregnating, moulding insulation, heating or drying of windings, stators, rotors or machines

Definitions

  • Particles are suspended in a chamber and then subjected to gas flow through the chamber and an outlet shutter or mask so that the insulating particle streams of different cross sections are formed sequentially as the gas flow leaves the chamber and enter the area in which the core being coated is displaced.
  • the area and atmosphere in which the core is disposed is thus free of particles except for the streams of particles passing through the area in the slots.
  • Excess particles leaving the slots are recovered in a second chamber outside of the area in which the core is disposed.
  • the second chamber is opposite to and spaced from the first-mentioned chamber and the core is disposed therebetween.
  • a reverse flow of insulating particle streams can be applied from the second chamber and recovery of excess material made at the first chamber.
  • This invention relates generally to rotors and stators of electrical rotary machines and more particularly to an apparatus for insulating the winding slots in rotor and stator cores and the like.
  • the slots of rotors and stators cores of electrical rotary machines have been provided during the manufacture of such machines with insulation inserts for receiving windings therein.
  • the slots of stator and rotor cores have been insulated by application of a plastic insulation coating over the surfaces of the core defining the individual slots.
  • the advantage of applying the insulation as a coating is that variable thicknesses can be applied and various complex shapes of slots can be insulated. Moreover, the application of insulation Coatings permits mass production tecnhiques to be applied. Various methods and apparatus are employed for applying these coatings, for example, a liquid plastic material may be applied, however, the coating material will tend to flow under the effect of gravity and is hard to control. Such insulation coatings are also applied by the fluidized-bed process which employs the use of nely divided plastic and electrically insulating powder. A durable insulating film or coating on the interior of the slot surfaces is formed with this technique.
  • the rotor or stator core is preheated and is then dipped into the bed of powder, which is suspended in air, after which the powder particles may be fused in 3,572,290 Patented Mar. 23, 1971 an industrial oven.
  • the use of the fluidized-process has several difficulties in that the whole part or component dipped into the bed is covered by a plastic insulating coating while it is intended that only the slots be coated. This results in a waste of material and requires an additional operation of removing the plastic material from those areas where it would cause interference structurally or otherwise.
  • the electrical machine core to be coated is placed in a chamber and then the slots thereof are subjected to a stream of insulating powder which is adhered to the slots.
  • the chamber in which the core is disposed is subjected to a vacuum or airflow in an attempt to keep the chamber free of excess particles that would adhere on areas of the core which are not desired to be coated.
  • a feature of the invention is the provision of an apparatus in which a sequence of streams having different cross sections, of finely divided heat fusible, insulating particles is directed through the individual slots of preheated stator and rotor cores to adhere the particles to substantially only the surfaces of the core defining the individual slots and thereby to form an insulating coating over the slot surfaces of controlled thickness.
  • the invention comprises an apparatus comprising means for receiving preheated cores having axially extending and angularly spaced slots thereon for receiving individual windings therein.
  • Means are provided for suspending finely divided particles of insulating material in a chamber provided with means defining a mask to preclude the application of particles to undesired portions of the cores.
  • the mask is provided with a plurality of spaced apertures communicating with the interior of the chamber and aligned coaxially with the slots of the core to be coated.
  • Means to apply a gaseous fluid under pressure to the mask is incorporated into the apparatus to flow the particles outwardly of the chamber through the apertures as a plurality of directed gaseous streams having the particles suspended therein and passing axially through the respective ones of the slots.
  • the preheated core has the particles coming into contact with it adhered thereto to form an insulating coating over the slots only which are further masked by a non-reactive mask cooperative with the core and assisting in defining with the axial slots therein channels through which the streams of powdered material pass.
  • FIG. 1 is a vertical cross-section view of an apparatus for applying the method according to the invention.
  • FIG. 2 is a diagrammatic side elevation view partly in section of the apparatus in FIG. 1.
  • a driven conveyor 1 transports individual cores of rotary electrical machines in axially spaced positions.
  • the cores comprise axially extending slots which are open on one side and at the opposite ends thereof and generally arranged angularly spaced.
  • a stator core 2 is transported between means comprising two devices 3, 3 defining a rst chamber and a second chamber as later described on opposite sides of the conveyor belt 1.
  • a spaceor chamber 4 Internally of each the devices, only one will be described in detail, is provided a spaceor chamber 4 for receiving in suspension therein fluidized, insulating material for use as hereinafter described.
  • Each device is provided with an axially displaceable shutter positioned in operation, closely adjacent the core, for example in the order of ve millimeters.
  • the shutter S comprises an aperture 6 and a mask portion 7 provided with radially spaced openings or apertures as illustrated in FIG. 2 and a third mask area 8 provided with openings therein arranged in the same arrangement as in the mask portion 7 with the openings having a smaller diameter or cross sectional area.
  • the openings in the mask portions 7 and 8 are disposed angularly spaced in position corresponding to the angular positions of the slots in the stator core 2 and are coaxial and in correspondence therewith as the stator 2 is moved into a position of alignment of the slots and openings or apertures.
  • a nozzle 10 connected to a source, not shown, of gaseous nid under pressure through conduit means 11.
  • a storage space 12 in which is contained a powdered plastic material having insulating qualities and made up of finely divided heat fusible particles.
  • the powered material enters a plurality of delivery nozzles of a distributing device 13 onto a shaking screen 15 driven by an electric motor 14 to iluidize the powder and temporarily suspend it in the chamber 4 as illustrated in the drawings.
  • the apparatus is provided on the bottom of the chamber with a dellector or chtite 16 that receives the material not used in the coating operation and transports it to a collecting space 17 from which a screw conveyor ⁇ 118 driven from the motor returns it to the storage space or chamber 12.
  • a cylinder 20 made of a material that will not react with the powder particles is disposed internally of the core thus masking the inner surfaces that are not to be coated and forming in conjunction with the slots 19 channels through which the streams of powder flow.
  • the stator 2 is preheated, as later explained, to a temperature which is above the reaction temperature of the plastic powdered material so that the heat fusible patricles passing through the slots 19 are deposited or adhered on the surfaces delining the slots and adhering to or fusing with each other upon deposition thereby forming a desired insulation coating.
  • Those particles that do not adhere are propelled out the opposite open end of the slots through a shutter 5 of the device 3 which is in a completely open position or may be in a position with an opening such as the opening 6 in registry with the core slots to allow the unused powder particles to enter a collecting space 17 of the chamber 3 in order to be further used in the apparatus as hereinafter described.
  • the apparatus according to the invention makes provision for transporting the cores to be insulated, for example the stator core 2 through a cleaning device 21 which is filled with cleaning vapors, for example perchlorineethylene saturated .vapors formed through the application of heat to a bath of perchlorine-ethylene fluid 22.
  • the stators core 2 leaves the cleaning device with a temperature of approximately 120 centigrade and enters a drying device 23 provided with a plurality of electrical heating elements 24 which further heat up and dry the stator core.
  • the preheated stator leaves the drying device with a temperature in the order of 220 centigrade and is transported to the area or zone in which the coating takes place between the two devices 3 and 3.
  • the coating material can be a powdered epoxy-resin powder insulating plastic which is heat fusible and can be heatset, for example the reaction temperature of which is in the order of 210 centigrade.
  • the sequence of masks used in the treatment of the core are irst the mask portion 8 and then the mask 7 and finally the mask portion having the large opening 6 therein.
  • the use of the smaller openings rst coats the interior of the slots and the larger openings cause the edges of the surfaces defining the slots adjacent the ends thereof to be coated with a coating rounding off the edges.
  • the largest opening can permit face surfaces adjacent the open end of the slots to be coated and insulated. lt being understood, that the stator core 2 is maintained aligned with the openings of the individual mask portions.
  • the operation may be made continuous by properly controlling the cycle of travel of the conveyor 1 and the selective positioning of the shutters 5 and 5 in sequence and maintaining the mask portions and apertures in them coaxially aligned with the core slots which can be maintained traveling.
  • air is employed to develop the streams of powdered material
  • other gaseous fluids may be employed.
  • a mixture of different heat set or fusible particles can be employed to carry out the invention.
  • the coating material can be a suitable heat fusible powdered material and the mask cylinder 20l can be made of a suitable material which will not react with the powder particles employed.
  • the cylinder is made, for example of polytetrafluorineethylene.
  • the invention provides for easily conditioning or treating the cores in preparation for adhering thereto the insulating material.
  • the invention provides for regulating the thickness of the coating as desired by controlling the length of time of application of particles.
  • the coating is mooth and free of irregularities generally found in coatings applied by methods making use of insulating materials in a fluid or plastic state.
  • the apparatus is highly efficient in recovery of material not used and the cleaning stage imparts a considerable amount of preheating to the cores during condensation of the cleaning vapors thereby conserving heat energy required for preheating.
  • Apparatus for insulating winding slots in cores for rotors, stators and the like for rotary electrical apparatus comprising, means for receiving individual cores having axially extending surfaces ⁇ defining a plurality of spaced slots for receiving windings therein and for positioning said cores in an area externally of said apparatus and atmosphere free of insulating particles, means for forming a suspension of nely divided, heat fusible, insulating particles directable as a -stream through the individual slots to adhere particles of said stream to the surfaces dening the individual slots thereby to form an insulating coating over said surfaces, means dening a rst chamber in which said suspension of particles is contained, means comprising shutter means having a plurality of spaced apertures communicating with the interior of said rst chamber and aligned coaXially with said slots of the core, means to apply gaseous uid under pressure interiorly of said rst chamber to said shutter means to flow said particles outwardly of said rst chamber through said apertures as
  • Apparatus according to claim 1 comprising means to preheat the individual cores before directing said streams of insulating particles through the individual slots.
  • Apparatus according to claim 1 in which said shutter means comprising said apertures has sets of apertures of different cross sections and is operable to apply said gaseous streams having particles suspended therein as streams of different cross sections in a sequence in which the cross section of the streams increases.
  • said means for forming said suspension in said chamber comprises a device having means to iluidize a powdered insulation material.
  • said shutter means comprises means defining a single aperature positionable in position selectively coaxially with said slots.
  • Apparatus according to claim 3 including a mask comprising a material to which said particles will not adhere positionable on said core and cooperative therewith in defining with said slots channels through which said streams of particles flow.
  • Apparatus according to claim 3 including means to apply a chemical agent to said cores for heating and cleaning said cores prior to directing said streams therethrough.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Power Engineering (AREA)
  • Manufacture Of Motors, Generators (AREA)
US696855A 1963-02-01 1968-01-10 Apparatus for insulating slots in stators and rotors of electrical rotary machines Expired - Lifetime US3572290A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DED0040803 1963-02-01

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US3572290A true US3572290A (en) 1971-03-23

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US696855A Expired - Lifetime US3572290A (en) 1963-02-01 1968-01-10 Apparatus for insulating slots in stators and rotors of electrical rotary machines
US698683A Expired - Lifetime US3470010A (en) 1963-02-01 1968-01-10 Method for applying streams of insulating particles to stator and rotor winding slots

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US698683A Expired - Lifetime US3470010A (en) 1963-02-01 1968-01-10 Method for applying streams of insulating particles to stator and rotor winding slots

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DK (1) DK108983C (da)
GB (1) GB1046086A (da)
SE (1) SE313618B (da)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4014286A (en) * 1975-04-25 1977-03-29 Zurik Donald E De Hot product marking system
US7572488B2 (en) 2003-07-22 2009-08-11 Robert Bosch Gmbh Method for applying an electrical insulation

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3617327A (en) * 1966-12-29 1971-11-02 Johns Manville Method and apparatus for applying a coating material
US3537875A (en) * 1968-03-04 1970-11-03 Gen Electric Method and apparatus for applying insulating material onto articles of manufacture
US3932691A (en) * 1970-03-03 1976-01-13 Wacker-Chemie Gmbh Method of insulating rotor plates
DE2830893B2 (de) * 1978-07-13 1980-07-03 Siemens Ag, 1000 Berlin Und 8000 Muenchen Verfahren zum Umhüllen von elektrischen Bauelementen, insbesondere Kondensatoren, durch Wirbelsintern
US5052332B1 (en) * 1990-03-15 1997-02-18 Electrostatic Technology Inc Apparatus and system for steam cleaning and coating of laminated articles
US20140209018A1 (en) * 2013-01-25 2014-07-31 GM Global Technology Operations LLC Method, system, and structure of stator with common insulating and varnishing resin
CN111468377B (zh) * 2020-04-24 2022-05-20 捷和电机（江西）有限公司 一种工业用电机的转子及其热电涂粉方法

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3185131A (en) * 1960-10-24 1965-05-25 Gen Motors Corp Apparatus for coating articles in a fluidized bed
US3291630A (en) * 1961-07-21 1966-12-13 Gen Motors Corp Method of coating cylindrical articles with thermoplastic material
US3136650A (en) * 1961-11-01 1964-06-09 Gen Electric Method for coating a surface of an article with a resin layer
US3247004A (en) * 1962-06-26 1966-04-19 Minnesota Mining & Mfg Method and apparatus for coating stators
US3355309A (en) * 1963-07-15 1967-11-28 Gen Electric Method and apparatus for applying coatings onto articles of manufacture
US3355310A (en) * 1963-07-15 1967-11-28 Gen Electric Method of forming layers of insulating material in slots of magnetic cores
US3261707A (en) * 1963-10-21 1966-07-19 Emerson Electric Co Stator coating

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4014286A (en) * 1975-04-25 1977-03-29 Zurik Donald E De Hot product marking system
US7572488B2 (en) 2003-07-22 2009-08-11 Robert Bosch Gmbh Method for applying an electrical insulation

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Publication number Publication date
US3470010A (en) 1969-09-30
SE313618B (da) 1969-08-18
DK108983C (da) 1968-03-04
GB1046086A (en) 1966-10-19

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