CA2106110A1 - Laminated articles and methods of making the same - Google Patents
Laminated articles and methods of making the sameInfo
- Publication number
- CA2106110A1 CA2106110A1 CA 2106110 CA2106110A CA2106110A1 CA 2106110 A1 CA2106110 A1 CA 2106110A1 CA 2106110 CA2106110 CA 2106110 CA 2106110 A CA2106110 A CA 2106110A CA 2106110 A1 CA2106110 A1 CA 2106110A1
- Authority
- CA
- Canada
- Prior art keywords
- article
- magnetic alloy
- particulate filler
- bond layer
- stack
- Prior art date
- Legal status (The legal status 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 status listed.)
- Abandoned
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
- B32B7/04—Interconnection of layers
- B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
- H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
- H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
- H01F1/16—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of sheets
- H01F1/18—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of sheets with insulating coating
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F3/00—Cores, Yokes, or armatures
- H01F3/02—Cores, Yokes, or armatures made from sheets
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K1/00—Details of the magnetic circuit
- H02K1/04—Details of the magnetic circuit characterised by the material used for insulating the magnetic circuit or parts thereof
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K15/00—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines
- H02K15/02—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines of stator or rotor bodies
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K15/00—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines
- H02K15/12—Impregnating, heating or drying of windings, stators, rotors or machines
Abstract
Abstract of the Invention This invention relates to an article comprising at least two layers of uncoated, magnetic alloy strip and a bond layer between the magnetic alloy strips wherein the bond layer comprises a particular filler having an average particle size sufficient to prevent interlayer shorting of the magnetic alloy strip. Invention also includes methods of making these articles.
Description
h~INa~D A~TI~L~ AND M~OD~ o~ ~agI~ T~B 8~N~
S Field of the Invention Invention relates to articles containing at least two layers of uncoated, magnetic alloy 5trip8 having bond layers hetween the magnetic alloy ~trips and ~ethods of making the same.
~ackqround o~ the Invention High frequency alternator and generator armatures and rotor cores are constructed from stack~ of thin gage laminations, These laminations are produced by stamping magnetic alloy strip. Typically the magnetic alloy strips are coated with a material, such as an inorganic phosphate coating. The coating permits high temperature annealing of the laminations and provides electrical insulation between laminations in the stacked core.
A problem associated with coating the magnetic alloy strips is uneven coating. Uneven coatings limit unit ef~iciency and increases unit-to-unit performance variations. The uneven coating also causes variations in bonded ~tack height dimensions.
Another problem caused by the coating is adhesive failures. The coating on the maynetic alloy strips interferes with the adhesive used to bind the magne~ic alloy strips. The coating causes weak bonds, which lead to dela~ination of the magn~tic alloy strips.
The armature and rotor cores are normally produced by bonding a large number of laminations into a single core assembly. Bonding is used ratber than mechanical joining to prev~nt interlaminar shorting a~d eddy current lose~
..
. .
.
.. . . ,: , - . . . , , . ~ . , ,, , .: . .. , ,., . . . ., . .: . . . . ,.; ,. .. ... :. , , ., .. . ,,, . , Another problem associated with armature and rotor core production is stamping burrs which are left on the laminations. The stamping burrs may have su~ficient height to introduce interlaminar shorting producing eddy currents within the stack. The atamping burr,s also- lead to uneven stacking of the,laminant.~layer~
It is desirous to produce a high efficiency armature or rotor core by minimizing the thickness of the adhesive layer between the magnetic alloy strips to improve e~fi-ciency and reduce unit-to-unit performance variation.
Summary of the Invention This invention relates to an article comprising at least two layers of uncoated, magnetic alloy strip and a bond layer between the magnetic alloy strips wherein the bond layer contains a particular Piller having an average particle size sufficient to prevent interlayer shorting of the magnetic alloy strip. Invention also includes methods of making these articles.
Brief Description~of the ~rawinqs Figure l refers to a cross section of two magnetic alloy strips bonded together.
Figure 2 is a cross section o~ a stack of bonded magnetic alloy strips, Detailed Description of the Invention As used in the specifications and claims herein, the term "interlayer or interlaminar -~horting" refers to contact between a magnetic alloy strip and a different magnetic alloy strip. This contact results in electrical current running between the layers. This electrical current, eddy current, re~uces the e~ficiency of the lam~nant core.
2 1 ~
~s used in the specification and claims, "stacking factor" refers to the ratio of actual magnetic material present in each stacked core to a core composed only of magnetic 7~aterial ~e.g., ~olid). ASTM D-71B describes the S proaedure ~or deter~ining ~he stacking ~actoriof the core.
The magnetic alloy strips used in the present invention are uncoated. The magnetic alloy strips are ge~erally available commercially as-rollad and annealed stock with a corrosion preventing oil coating and vapor barrier seal. The magnetic alloy strips are often referred to as transformer stock. The magnetic alloy strips include silicon steel alloy, nickel steel alloy, and valadium permadur. A particularly useful magnetic alloy strip comprises a silicon steel alloy strip, pre~erably a silicon steel alloy strip having up to 9% by weight, more preferably up to about 6% by weight silicon. The magnetic alloy strips generally have a thickness less than about 0.51 ~n (0.02 inches).
A bond layer is placed between the uncoated, magnetic alloy strips. The bond layer includes a particular filler having an averaqe particle size su~ficient to prevent interlayer shorting of the magnetic alloy strips. In one embodiment the particle ~iller has an average particle size from about 0.5, or about 0.9, or about 1.0 . The particle size of the filler may be up to abo7~t 8, or to about 7, or to about 6 microns. In one embodiment the particulate filler has a median partiGle si~e fro~ about 0.5, or about 0,9 or about 1 up to about 2, or to about 1.8, or to about 1.6, or to about 1.4 micron~. In another e7nbodiment the particulate ~iller has a mean particle size from about 0.5, or about 1, or about 2 up to about 8, or to about, or to about 6 microns. The mean particle size is determined by the Malvern 3600 Particle Size Analyzer. The particulate ~0~
filler has a narrow particle distribution. In one embodiment, the particulate filler has a particle size distribution by vol~me of 100% less than about 20 microns, or about 99.9% less than about 15 microns, and or about 97.2~ less than about 11 microns. --The particulate fillers are generally used at a level ~rom about 5%, or about 7%, ox about 9% up to about 25~, or to about 18%, or to about 16%, or about 14% by weight of the adhesive and particulate filler. In one embodiment, the partlculate filler is used with an inorganic binder. In this embodiment, the particulate filler is generally present in an amount from about 9~, or about 12% up to about 25%, or to about 22%, or to about 20% by weight of the inorganic binder and particulate filler.
The particulate filler may be any non-conductive filler having a particle size, axi described herein.
Examples of particulate fillers include ceramic microspheres, and chopped glass fibers. In one embodimint, the particulate filler compri~es a ceramic microsphere, and especially a hollow, thick-walled, silica-alumina alloy microsphere. An example of this ceramic microsphere is Zeeospheres~ fillers available commercially from 3M
Chemical Company. A particularly useful .ceramic microsphere is Zeeosphere~ 200. Zeeosphere~ 200 is characteri~ed as having a median particle ~ize of 1.3 microns; a mean particle size of a particle size of 5.3 microns; a distribution by volume of 90% less than 9.0 microns, 50~ less than 5.1 microns, and 10% less than 2.2 microns. The residual weight percent retained on a 325 mesh (45 micron) screen is 0.01% ~determined by ASTM D-1~5~.
2 ~
The particulate fill~r i~ combined with an adhesive to form the ~ond layer (B). The bond layer, or bondline, generally has a thickness ~rom about 3, or about 5, or about 7 up to about 25, or about 20, or about 15 microns.
S The bond layer is ~general~ *hi~ik enough ~to provid~
electrical insulation b~bwe~n the,~gnetic alloy ætrips but thin enough to provide optimal stacking factor. I
As described above, the bond layer also includes a cured adhesive. The adhesive may be phenolic, silicon rubber or an epoxy adhesive. Generally, epoxy adhesives are preferred. Epoxy adhesives are generally diglycidyl ethers of bisphenol A derived fxom bisphenol A and epichlorohydrin. One way of preparing epoxy resins is a two part adhesive package. The first part contains a dichlorohydrin of bisphenol A. The other part contains a curing agent. Curing agents include anhydrides, ~mines, polyamines, Lewis acids, etc. Important classes of curing agents include polyamines, polyaminoamides tformed from polyamines and dimerized fatty acids e.g., acids containing 1 to 30 carbon atoms~, polyphenols, polymeric thiols, polycarboxylic acids, and anhydrides. An example of a seful epoxy adhesive is Bondma-Rter E645 adhesive, available commercially from National S~arch and Chemical Company.
In another embodiment, the binder composition also includes a cured inorganic binder. The inorganic bindi~r together with the particulate filler form an inorganic bond layer between the uncoated, magnetic alloy steel strips.
An example of a useful inorganic binder is Cerama-bind~
binder available commercially from Aremco Products Inc. A
particularly useful inorganic binder is Cerama-bind~ 644.
:.
' ' '. :
2 1 ~
The invention is further exemplified with reference to the drawings. .In ~i~ure 1, ~agnetic alloy strips 11 are bonded together with bonding layer 12. Bonding layer 12 has particulate matter 13 disper~ed within the bonding layer. -~
In figure 2, the stack is compo ed of magnetic alloy strip layers 21 having bonding layers 22 between each layer of magnetic alloy strip.
The invention also relates to a method o~ preparing an electrical laminant comprising the steps of ~1) coating a magnet.ic alloy strip with a binding composition including a particulate ~iller having an average particle size sufficient to prevent interlaminar shorting, t2) forming a stack of coated magnetic alloy strips, (3) applying pres-sure to the stack, and (4) curing the binding composition.
In another ambodiment, the invention also relates to a method of preparing an electrical laminant comprising the steps of (1) forming a stack of uncoated, magnetic alloy strips, (2) coatiny tha magnetic alloy strips with a binding composition including a particulate *iller having an average particle size sufficient to prevent interlaminar shorting, (3) applying pressure to the stack, and (4) curing the binding composition.
Generally, the uncoated, magnetic alloy ~trips are cleaned and degreased. Cleaning is generally accomplished by using methyl ethyl ketone or any degreasing solvent.
The magnetic alloy strips are then coated with a binding composition. The amount of time between degre.asing and coating should be ~inimized to prevent rusting of the magnetic alloy stripsO The magnetic alloy Rtrips may be coated by any means known to those in the art, such as painting, spraying, dip coating, etc.
` ' . . .. : . ., ~ , .. .
2 1 ~
In one embodi~ent, the ma~netic alloy strips are vacuum impregnated with the binding composition.
Generally, the individual cleaned, uncoated ~agnetic alloy strips, or a stack (loosely bound) of uncoated, magnetic alloy strip~ are placed under~vacuum in a ~uitable vessel.
The vessel ~s then fl~oded with -the binding composition.
The magnetic alloy strips, or stacks thereof generally remain in the binding composition for about 15-30 minutes.
Vacuum is released and excess binding composition is drained from the individual strips or stack. The vacuum ~enerally acts to prevent inclusion o~ air bub~les in the coating of the individual alloy strips or stacks. The vacuum is generally below about 100 mm Hg, or below about 50 mm Hg. A vacuum of 20-30 ~m Hg is particularly usePul.
In another embodiment, individual magnetic alloy strips are placed in the suitable vessel. A vacuum is pulled on the vessel and the strips are dipped into a binding composition. The vacuum is released and the strips are removed from the binding composition and dried.
In the present invention, the coated magnetic alloy strip~ are formed int~ a stack as is known to those in the art. The exact ~tacking arrangement is not critical to the pre~ent invention. After the individual alloy strips have been coated and formed into a stack or coated as a stack, pressure is applied to the stack. Pressure can be applied by any means known to tho~e skilled in the art, such as by applying spring pressure. The pressure is generally from about 4,500, or about 6,000, or about 9,000, up to about 20,000, or about 18,000 newtons (from about 1,000 to about 4,400 pounds).
2 ~
The binding composition is cured while maintaining pressure on the stack. ~uring generally occurs at a temperature of about 65C, or abou~ 80C~ or about 125C up to about 240CI or to about 200C (from about 150F to 5about 450~F)~ Generally,~thel curin~ occurs withi~ about 0.5, or about l hours u~o ~ou~l9~hours,~or to about 3 hours. The curing time begins after the stack has reached curing temperatures. After curing the binding composi~ion the stack is generally allowed to return to ambient 10temperatures and the pressure is released from the stack.
In another embodiment, invention relates to a composi- -tion useful in binding electrical laminants comprising (i) an epoxy adhesive and (ii) a hollow, thick-walled, silica-15alumina alloy microsphere. The epoxy adhesive and silica-alumina alloy microsphere have been described above.
: ' The following example relates to the articles, methods, and compositions of the present invention. Unless 20otherwise indicated, as used in the examples as well as elsewhere in the specification and claims, parts are parts by weight, and temperatures is in degr~e celsius.
Exam~le 25A binding composition is prepared by mixing 45 parts o~ Bondmaster E645 is added to 49 parts of methyl ethyl ketone. Then, 6 parts of Ze~osphere~ 200 is added to the mixture and blended until a uniform composition is ob-tained. The viscosity of the mixture is 30 s~conds in a #1 30Zahn cup at room temp~rature.
Lamination surfaces of a transformer stock having about 6% silicon, are cleaned and degreased using methyl ethyl keton~. The binding composition above is sprayed on 35the lamination sur~ac~s to a dry film thickness o~ 12.5 to , 2 1 ~
25 mm ~0.5 to 1 mill. Solvent is removed at about 65C for lo to 60 minute~ in a forced air oven. The coated lami~ants are stackad in a ~ixture. A clamping force of 4,500 to 18,000 newtons (1,000 - 4,000 pounds gage) is applied to the stack by 6pring. The clamped stack is placed in a forced air oven at 175e for 2 hours. The two hours begin after the stac~ has reached oven temperature.
After two hours, the stack is removed and allowed to cool to room temperature. After cooling to room temperature the spring pressure is removed from the stack. The stack is then removed and useable in a transformer, stator or rotor, as known to those in the art.
.
Table_l In Table 1, laminations ar~ made by the above described procedure. Table 1 contains data comparing th~
effects of the binding com~ositions on stacking factor and resistivity o~ uncoated, magn~tic alloy strips. Examples 1, 2, and 3 r~late to the present invention and include particulate filler (Zeeosphere0 200) in the binding compo~ition. Examples 4, 5, and 6 are co~parative examples and relate to laminations made from bare ~ransformer stock without the use of particulate filler. Examples 7, 8, and g are comparative examples and relate to coated magnetic alloy strips which are bound together by the epoxy adhesive, Bondmaster E645.
2iO61 ~0 Tuble 1 _ ~_ ~ _ . . _ I
Ex. L~min~tion Filler Force Bond Ave. Surf~ce ~e~tcns) Thicknos~ St~cking Resistivity L ~icrons~ F~etor ~AST ~718) ¦ . .
l Rare Yo6 4500 10.3 0.926 84.30 ¦
1---- - -- - ---- ------ - _ I
2 Baro Yes 9000 7.9 0.9U 7 S0 I .
~ _ ___ ~ .. I , .
S Field of the Invention Invention relates to articles containing at least two layers of uncoated, magnetic alloy 5trip8 having bond layers hetween the magnetic alloy ~trips and ~ethods of making the same.
~ackqround o~ the Invention High frequency alternator and generator armatures and rotor cores are constructed from stack~ of thin gage laminations, These laminations are produced by stamping magnetic alloy strip. Typically the magnetic alloy strips are coated with a material, such as an inorganic phosphate coating. The coating permits high temperature annealing of the laminations and provides electrical insulation between laminations in the stacked core.
A problem associated with coating the magnetic alloy strips is uneven coating. Uneven coatings limit unit ef~iciency and increases unit-to-unit performance variations. The uneven coating also causes variations in bonded ~tack height dimensions.
Another problem caused by the coating is adhesive failures. The coating on the maynetic alloy strips interferes with the adhesive used to bind the magne~ic alloy strips. The coating causes weak bonds, which lead to dela~ination of the magn~tic alloy strips.
The armature and rotor cores are normally produced by bonding a large number of laminations into a single core assembly. Bonding is used ratber than mechanical joining to prev~nt interlaminar shorting a~d eddy current lose~
..
. .
.
.. . . ,: , - . . . , , . ~ . , ,, , .: . .. , ,., . . . ., . .: . . . . ,.; ,. .. ... :. , , ., .. . ,,, . , Another problem associated with armature and rotor core production is stamping burrs which are left on the laminations. The stamping burrs may have su~ficient height to introduce interlaminar shorting producing eddy currents within the stack. The atamping burr,s also- lead to uneven stacking of the,laminant.~layer~
It is desirous to produce a high efficiency armature or rotor core by minimizing the thickness of the adhesive layer between the magnetic alloy strips to improve e~fi-ciency and reduce unit-to-unit performance variation.
Summary of the Invention This invention relates to an article comprising at least two layers of uncoated, magnetic alloy strip and a bond layer between the magnetic alloy strips wherein the bond layer contains a particular Piller having an average particle size sufficient to prevent interlayer shorting of the magnetic alloy strip. Invention also includes methods of making these articles.
Brief Description~of the ~rawinqs Figure l refers to a cross section of two magnetic alloy strips bonded together.
Figure 2 is a cross section o~ a stack of bonded magnetic alloy strips, Detailed Description of the Invention As used in the specifications and claims herein, the term "interlayer or interlaminar -~horting" refers to contact between a magnetic alloy strip and a different magnetic alloy strip. This contact results in electrical current running between the layers. This electrical current, eddy current, re~uces the e~ficiency of the lam~nant core.
2 1 ~
~s used in the specification and claims, "stacking factor" refers to the ratio of actual magnetic material present in each stacked core to a core composed only of magnetic 7~aterial ~e.g., ~olid). ASTM D-71B describes the S proaedure ~or deter~ining ~he stacking ~actoriof the core.
The magnetic alloy strips used in the present invention are uncoated. The magnetic alloy strips are ge~erally available commercially as-rollad and annealed stock with a corrosion preventing oil coating and vapor barrier seal. The magnetic alloy strips are often referred to as transformer stock. The magnetic alloy strips include silicon steel alloy, nickel steel alloy, and valadium permadur. A particularly useful magnetic alloy strip comprises a silicon steel alloy strip, pre~erably a silicon steel alloy strip having up to 9% by weight, more preferably up to about 6% by weight silicon. The magnetic alloy strips generally have a thickness less than about 0.51 ~n (0.02 inches).
A bond layer is placed between the uncoated, magnetic alloy strips. The bond layer includes a particular filler having an averaqe particle size su~ficient to prevent interlayer shorting of the magnetic alloy strips. In one embodiment the particle ~iller has an average particle size from about 0.5, or about 0.9, or about 1.0 . The particle size of the filler may be up to abo7~t 8, or to about 7, or to about 6 microns. In one embodiment the particulate filler has a median partiGle si~e fro~ about 0.5, or about 0,9 or about 1 up to about 2, or to about 1.8, or to about 1.6, or to about 1.4 micron~. In another e7nbodiment the particulate ~iller has a mean particle size from about 0.5, or about 1, or about 2 up to about 8, or to about, or to about 6 microns. The mean particle size is determined by the Malvern 3600 Particle Size Analyzer. The particulate ~0~
filler has a narrow particle distribution. In one embodiment, the particulate filler has a particle size distribution by vol~me of 100% less than about 20 microns, or about 99.9% less than about 15 microns, and or about 97.2~ less than about 11 microns. --The particulate fillers are generally used at a level ~rom about 5%, or about 7%, ox about 9% up to about 25~, or to about 18%, or to about 16%, or about 14% by weight of the adhesive and particulate filler. In one embodiment, the partlculate filler is used with an inorganic binder. In this embodiment, the particulate filler is generally present in an amount from about 9~, or about 12% up to about 25%, or to about 22%, or to about 20% by weight of the inorganic binder and particulate filler.
The particulate filler may be any non-conductive filler having a particle size, axi described herein.
Examples of particulate fillers include ceramic microspheres, and chopped glass fibers. In one embodimint, the particulate filler compri~es a ceramic microsphere, and especially a hollow, thick-walled, silica-alumina alloy microsphere. An example of this ceramic microsphere is Zeeospheres~ fillers available commercially from 3M
Chemical Company. A particularly useful .ceramic microsphere is Zeeosphere~ 200. Zeeosphere~ 200 is characteri~ed as having a median particle ~ize of 1.3 microns; a mean particle size of a particle size of 5.3 microns; a distribution by volume of 90% less than 9.0 microns, 50~ less than 5.1 microns, and 10% less than 2.2 microns. The residual weight percent retained on a 325 mesh (45 micron) screen is 0.01% ~determined by ASTM D-1~5~.
2 ~
The particulate fill~r i~ combined with an adhesive to form the ~ond layer (B). The bond layer, or bondline, generally has a thickness ~rom about 3, or about 5, or about 7 up to about 25, or about 20, or about 15 microns.
S The bond layer is ~general~ *hi~ik enough ~to provid~
electrical insulation b~bwe~n the,~gnetic alloy ætrips but thin enough to provide optimal stacking factor. I
As described above, the bond layer also includes a cured adhesive. The adhesive may be phenolic, silicon rubber or an epoxy adhesive. Generally, epoxy adhesives are preferred. Epoxy adhesives are generally diglycidyl ethers of bisphenol A derived fxom bisphenol A and epichlorohydrin. One way of preparing epoxy resins is a two part adhesive package. The first part contains a dichlorohydrin of bisphenol A. The other part contains a curing agent. Curing agents include anhydrides, ~mines, polyamines, Lewis acids, etc. Important classes of curing agents include polyamines, polyaminoamides tformed from polyamines and dimerized fatty acids e.g., acids containing 1 to 30 carbon atoms~, polyphenols, polymeric thiols, polycarboxylic acids, and anhydrides. An example of a seful epoxy adhesive is Bondma-Rter E645 adhesive, available commercially from National S~arch and Chemical Company.
In another embodiment, the binder composition also includes a cured inorganic binder. The inorganic bindi~r together with the particulate filler form an inorganic bond layer between the uncoated, magnetic alloy steel strips.
An example of a useful inorganic binder is Cerama-bind~
binder available commercially from Aremco Products Inc. A
particularly useful inorganic binder is Cerama-bind~ 644.
:.
' ' '. :
2 1 ~
The invention is further exemplified with reference to the drawings. .In ~i~ure 1, ~agnetic alloy strips 11 are bonded together with bonding layer 12. Bonding layer 12 has particulate matter 13 disper~ed within the bonding layer. -~
In figure 2, the stack is compo ed of magnetic alloy strip layers 21 having bonding layers 22 between each layer of magnetic alloy strip.
The invention also relates to a method o~ preparing an electrical laminant comprising the steps of ~1) coating a magnet.ic alloy strip with a binding composition including a particulate ~iller having an average particle size sufficient to prevent interlaminar shorting, t2) forming a stack of coated magnetic alloy strips, (3) applying pres-sure to the stack, and (4) curing the binding composition.
In another ambodiment, the invention also relates to a method of preparing an electrical laminant comprising the steps of (1) forming a stack of uncoated, magnetic alloy strips, (2) coatiny tha magnetic alloy strips with a binding composition including a particulate *iller having an average particle size sufficient to prevent interlaminar shorting, (3) applying pressure to the stack, and (4) curing the binding composition.
Generally, the uncoated, magnetic alloy ~trips are cleaned and degreased. Cleaning is generally accomplished by using methyl ethyl ketone or any degreasing solvent.
The magnetic alloy strips are then coated with a binding composition. The amount of time between degre.asing and coating should be ~inimized to prevent rusting of the magnetic alloy stripsO The magnetic alloy Rtrips may be coated by any means known to those in the art, such as painting, spraying, dip coating, etc.
` ' . . .. : . ., ~ , .. .
2 1 ~
In one embodi~ent, the ma~netic alloy strips are vacuum impregnated with the binding composition.
Generally, the individual cleaned, uncoated ~agnetic alloy strips, or a stack (loosely bound) of uncoated, magnetic alloy strip~ are placed under~vacuum in a ~uitable vessel.
The vessel ~s then fl~oded with -the binding composition.
The magnetic alloy strips, or stacks thereof generally remain in the binding composition for about 15-30 minutes.
Vacuum is released and excess binding composition is drained from the individual strips or stack. The vacuum ~enerally acts to prevent inclusion o~ air bub~les in the coating of the individual alloy strips or stacks. The vacuum is generally below about 100 mm Hg, or below about 50 mm Hg. A vacuum of 20-30 ~m Hg is particularly usePul.
In another embodiment, individual magnetic alloy strips are placed in the suitable vessel. A vacuum is pulled on the vessel and the strips are dipped into a binding composition. The vacuum is released and the strips are removed from the binding composition and dried.
In the present invention, the coated magnetic alloy strip~ are formed int~ a stack as is known to those in the art. The exact ~tacking arrangement is not critical to the pre~ent invention. After the individual alloy strips have been coated and formed into a stack or coated as a stack, pressure is applied to the stack. Pressure can be applied by any means known to tho~e skilled in the art, such as by applying spring pressure. The pressure is generally from about 4,500, or about 6,000, or about 9,000, up to about 20,000, or about 18,000 newtons (from about 1,000 to about 4,400 pounds).
2 ~
The binding composition is cured while maintaining pressure on the stack. ~uring generally occurs at a temperature of about 65C, or abou~ 80C~ or about 125C up to about 240CI or to about 200C (from about 150F to 5about 450~F)~ Generally,~thel curin~ occurs withi~ about 0.5, or about l hours u~o ~ou~l9~hours,~or to about 3 hours. The curing time begins after the stack has reached curing temperatures. After curing the binding composi~ion the stack is generally allowed to return to ambient 10temperatures and the pressure is released from the stack.
In another embodiment, invention relates to a composi- -tion useful in binding electrical laminants comprising (i) an epoxy adhesive and (ii) a hollow, thick-walled, silica-15alumina alloy microsphere. The epoxy adhesive and silica-alumina alloy microsphere have been described above.
: ' The following example relates to the articles, methods, and compositions of the present invention. Unless 20otherwise indicated, as used in the examples as well as elsewhere in the specification and claims, parts are parts by weight, and temperatures is in degr~e celsius.
Exam~le 25A binding composition is prepared by mixing 45 parts o~ Bondmaster E645 is added to 49 parts of methyl ethyl ketone. Then, 6 parts of Ze~osphere~ 200 is added to the mixture and blended until a uniform composition is ob-tained. The viscosity of the mixture is 30 s~conds in a #1 30Zahn cup at room temp~rature.
Lamination surfaces of a transformer stock having about 6% silicon, are cleaned and degreased using methyl ethyl keton~. The binding composition above is sprayed on 35the lamination sur~ac~s to a dry film thickness o~ 12.5 to , 2 1 ~
25 mm ~0.5 to 1 mill. Solvent is removed at about 65C for lo to 60 minute~ in a forced air oven. The coated lami~ants are stackad in a ~ixture. A clamping force of 4,500 to 18,000 newtons (1,000 - 4,000 pounds gage) is applied to the stack by 6pring. The clamped stack is placed in a forced air oven at 175e for 2 hours. The two hours begin after the stac~ has reached oven temperature.
After two hours, the stack is removed and allowed to cool to room temperature. After cooling to room temperature the spring pressure is removed from the stack. The stack is then removed and useable in a transformer, stator or rotor, as known to those in the art.
.
Table_l In Table 1, laminations ar~ made by the above described procedure. Table 1 contains data comparing th~
effects of the binding com~ositions on stacking factor and resistivity o~ uncoated, magn~tic alloy strips. Examples 1, 2, and 3 r~late to the present invention and include particulate filler (Zeeosphere0 200) in the binding compo~ition. Examples 4, 5, and 6 are co~parative examples and relate to laminations made from bare ~ransformer stock without the use of particulate filler. Examples 7, 8, and g are comparative examples and relate to coated magnetic alloy strips which are bound together by the epoxy adhesive, Bondmaster E645.
2iO61 ~0 Tuble 1 _ ~_ ~ _ . . _ I
Ex. L~min~tion Filler Force Bond Ave. Surf~ce ~e~tcns) Thicknos~ St~cking Resistivity L ~icrons~ F~etor ~AST ~718) ¦ . .
l Rare Yo6 4500 10.3 0.926 84.30 ¦
1---- - -- - ---- ------ - _ I
2 Baro Yes 9000 7.9 0.9U 7 S0 I .
~ _ ___ ~ .. I , .
3 Bare Yes 18,000 8.2 0.940 1.08 I .
I_ ~ _ _ __ _ I .... .
B~re ~one 4500 3.1 0.976 0.19 B~re ~on~ gO00 1.1 0.992 0.03 6 Bare None 18,000 0.4 0.997 0.03 7 Cost~d None 4500 2.1 0.938 9.53 ¦ .
_ . _ . . ._ _ _ .
0 8 Coated Uone 9000 2.8 0.934 7.69 9 Co~ted ~one 18,000 0.8 ' 0.948 1.75 = .-= i- == ~ .. -- ---=
As can be seen from the above table, stacks made with ~.
bare lamination and filler (Examples 1, 2, and 3) have :
lower dimensional variation and higher resistivity compared to stacks made with bare laminations and no filler (Examples 4, 5, and ~). Examples l, 2, and 3 have more consistent stacking factor and bondline thickness at different clamping forces. Examples 1, 2, and 3 show no :
bondline separation (delamination~. Applicants have discovered that the use of a particulate filler leads to lamination separation control which provides consistent stack density, consistent stack height and ~inimized stack shorting.
`` 2:1 06~
While the invention has been explained in relation to its preferred embodiments, it is to be understood that various modifications thereof will become apparent to those skilled in the art upon reading the specifiaation.
S Therefore, it is to be unde~stood that the invention disclosed herein is intended to cover ~uch ~odifications as well as fall within the scope of the appéndant claim.
. - . - . . .. , , . - ,.. . . . . .. , : -: . ~ .. : .: . ... : : , . , : : : :
.. , .,: ,:; .,. -., . , . . : .. . : . , :~. .
I_ ~ _ _ __ _ I .... .
B~re ~one 4500 3.1 0.976 0.19 B~re ~on~ gO00 1.1 0.992 0.03 6 Bare None 18,000 0.4 0.997 0.03 7 Cost~d None 4500 2.1 0.938 9.53 ¦ .
_ . _ . . ._ _ _ .
0 8 Coated Uone 9000 2.8 0.934 7.69 9 Co~ted ~one 18,000 0.8 ' 0.948 1.75 = .-= i- == ~ .. -- ---=
As can be seen from the above table, stacks made with ~.
bare lamination and filler (Examples 1, 2, and 3) have :
lower dimensional variation and higher resistivity compared to stacks made with bare laminations and no filler (Examples 4, 5, and ~). Examples l, 2, and 3 have more consistent stacking factor and bondline thickness at different clamping forces. Examples 1, 2, and 3 show no :
bondline separation (delamination~. Applicants have discovered that the use of a particulate filler leads to lamination separation control which provides consistent stack density, consistent stack height and ~inimized stack shorting.
`` 2:1 06~
While the invention has been explained in relation to its preferred embodiments, it is to be understood that various modifications thereof will become apparent to those skilled in the art upon reading the specifiaation.
S Therefore, it is to be unde~stood that the invention disclosed herein is intended to cover ~uch ~odifications as well as fall within the scope of the appéndant claim.
. - . - . . .. , , . - ,.. . . . . .. , : -: . ~ .. : .: . ... : : , . , : : : :
.. , .,: ,:; .,. -., . , . . : .. . : . , :~. .
Claims (20)
1. An article comprising (A) at least two layers of an uncoated, magnetic alloy strip, and (B) at least one bond layer between the magnetic alloy strips, wherein the bond layer includes a particulate filler having an average particle size sufficient to prevent interlayer shorting of the magnetic alloy strips.
2. The. article of claim 1 wherein (A) comprises transformer stock.
3. The article of claim 1 wherein (A) comprises a silicon steel alloy, nickel steel alloy, or vanadium permadur.
4. The article of claim 1 wherein the particulate filler has an mean particle size from about 0.5 to about 8 microns.
5. The article of claim 1 wherein the particulate filler is selected from the group consisting of a ceramic microsphere, and a chopped glass fiber.
6. The article of claim 1 wherein the particulate filler comprises a hollow, thick-walled, silica-alumina alloy microsphere.
7. The article of claim 1 wherein the bond layer has an average thickness from about 3 to about 25 microns.
8. The article of claim 1 wherein the bond layer comprises a cured adhesive.
9. The article of claim 1 wherein the adhesive comprises a cured epoxy adhesive.
10. The article of claim 1 wherein the bond layer comprises a cured inorganic binder.
11. An article comprising (A) at least two layers of an uncoated, magnetic alloy strip, and (B) at least one bond layer between the magnetic alloy strips, wherein the bond layer includes a particulate filler having an average particle size from about 0.5 to about 8 microns and the bond layer has an average thickness from about 3 to about 25 microns.
12. A method of preparing an electrical laminant comprising the steps of (1) coating a magnetic alloy strip with a binding composition including a particulate filler having an average particle size sufficient to prevent interlaminar shorting, (2) forming a stack of coated magnetic alloy strips, (3) applying pressure to the stack, and (4) curing the binding composition.
13. The method of claim 12 wherein the coating in step (1) comprises vacuum impregnation-coating.
14. The article of claim 12 wherein the particulate filler is selected from the group consisting of a ceramic microsphere, and a chopped glass fiber.
15. The article of claim 12 wherein the particulate filler comprises a hollow, thick-walled, silica-alumina alloy microsphere.
16. The method of claim 12 wherein the pressure in step (3) comprises from about 4500 to about 20,000 newtons.
17. The method of claim 12 wherein the curing in step (4) occurs from about 65°C to about 250°C.
18. A method of preparing an electrical laminant comprising the steps of (1) forming a stack of uncoated, magnetic alloy strips, (2) coating the stack of magnetic alloy strips with a binding composition including a particulate filler having an average particle size suffi-cient to prevent interlaminar shorting, (3) applying pressure to the stack, and (4) curing the binding composi-tion.
19. A composition useful in binding electrical laminants comprising (i) an epoxy adhesive and (ii) a hollow, thick-walled, silica-alumina alloy sphere.
20. An article comprising a transformer, stator, or rotor containing the article of claim 1.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US94931792A | 1992-09-22 | 1992-09-22 | |
| US07/949,317 | 1992-09-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2106110A1 true CA2106110A1 (en) | 1994-03-23 |
Family
ID=25488905
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2106110 Abandoned CA2106110A1 (en) | 1992-09-22 | 1993-09-14 | Laminated articles and methods of making the same |
Country Status (3)
| Country | Link |
|---|---|
| CA (1) | CA2106110A1 (en) |
| DE (1) | DE4331787A1 (en) |
| GB (1) | GB2271219A (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19901313C1 (en) * | 1999-01-15 | 2000-10-12 | Thyssenkrupp Stahl Ag | Composite material in the form of a band or sheet made of two steel cover plates that can be resistance-welded to one another and an intermediate layer made of a filler, process for its production and plant for carrying out the process |
| JP2003324869A (en) * | 2002-05-08 | 2003-11-14 | Daikin Ind Ltd | Motor and compressor |
| FR2888390B1 (en) * | 2005-07-08 | 2009-05-22 | Cnes Epic | METHOD FOR MANUFACTURING MAGNETIC LAMINATE CIRCUIT |
| KR101323522B1 (en) | 2006-08-14 | 2013-10-29 | 브로제 파르초이크타일레 게엠베하 운트 코. 카게, 뷔르츠부르크 | Rotor for an electric motor |
| DE102011079843A1 (en) * | 2011-07-26 | 2013-01-31 | Siemens Aktiengesellschaft | Electric machine with low-mass design in magnetically active parts |
| DE102012106260A1 (en) * | 2012-07-12 | 2014-01-16 | Hella Kgaa Hueck & Co. | Multiphase stray field transformer for storage and filtering |
| AT516197A1 (en) | 2014-09-05 | 2016-03-15 | Voestalpine Stahl Gmbh | Coil and method of making a coil-wound electrical steel laminate |
| DE102020208689A1 (en) | 2020-07-10 | 2022-01-13 | Elringklinger Ag | Connection material, sheet metal stack, machine component and electric motor |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3029403A (en) * | 1958-05-23 | 1962-04-10 | Honeywell Regulator Co | Magnetic core structures |
| US3186867A (en) * | 1962-10-12 | 1965-06-01 | Gen Electric | Process for coating ferrous material and material coated by such process |
| DE3244823A1 (en) * | 1982-12-03 | 1984-06-07 | E. Blum GmbH & Co, 7143 Vaihingen | ELECTRIC SHEET FOR PRODUCING LAMINATED IRON CORES FOR STATIC OR DYNAMIC ELECTRICAL MACHINES |
-
1993
- 1993-09-14 CA CA 2106110 patent/CA2106110A1/en not_active Abandoned
- 1993-09-14 GB GB9318991A patent/GB2271219A/en not_active Withdrawn
- 1993-09-18 DE DE19934331787 patent/DE4331787A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| GB2271219A (en) | 1994-04-06 |
| GB9318991D0 (en) | 1993-10-27 |
| DE4331787A1 (en) | 1994-04-21 |
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