CA1137149A - Hysteresis motor having amorphous metal rotor - Google Patents
Hysteresis motor having amorphous metal rotorInfo
- Publication number
- CA1137149A CA1137149A CA000331279A CA331279A CA1137149A CA 1137149 A CA1137149 A CA 1137149A CA 000331279 A CA000331279 A CA 000331279A CA 331279 A CA331279 A CA 331279A CA 1137149 A CA1137149 A CA 1137149A
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- CA
- Canada
- Prior art keywords
- machine
- rotor
- axis
- amorphous metal
- coils
- 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.)
- Expired
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- Manufacture Of Motors, Generators (AREA)
Abstract
Abstract of the Disclosure A rotor is fabricated of a plurality of strips of thin amorphous metal wound side by side into adjacent coils about an axis, the flat sides of the strips being parallel to the axis. The rotor material is annealed to increase its coercive force to a value which may be up to 100 oersteds, rendering the rotor useful in a hysteresis type motor.
Description
~137~ RD 10,232 This invention relates to hysteresis machines and more specifically to a hysteresis machine having a rotor comprising a coil of amorphous metal tape which has been annealed to increase its coercivity.
Hysteresis machines, such as motors, are well known selt-starting synchronous machines employing the hysteresis properties of the rotor. The driving force is provided by the rotating stator field which m~gnetizes the rotor. If the power supply 1~ frequency remains constant, rotor speed remains constant even if there are changes, within limits, in applied voltage, ambient temperature and attached torque load. Moreover, the motor speed is not affected by manufacturing variations, within pre-determined limits. Consequently, the hysteresis synchronous machine can be used in virtually any applciation requiring synchronous motors.
Torque developed by the motor is proportional to area of the rotor material hysteresis loop, while exciting current for the motor is determined by coercive force of the rotor material. Thus, a coercive force should be selected for a particular hysteresis ~1~7~4~ RD 10,232 machine application which balances exciting current against the available torque for the machine.
The cost of hysteresis motor rotor material is several dollars per pound at the present time.
Use of less expensive material for the hysteresis motor would be desirable. Amorphous metals have recently become available which have good magnetic properties and have a potential cost of one-tenth at of metals now used for hysteresis motors.
Amorphous metals, however, are not available in a form convenient for manufacture of conventional laminated rotors. Thus the metal is in the form of a tape which is about 0.005 to 0.003 inch thick and in widths of up to about 2 inches. The amorphous metal tape also has very low coercive force, of the order of from 0.01 to 0.1 oersteds.
Amorphous metal taps having magnetic properties desired for application to electric machines are disclosed in United States Letters Patents, 3,856,513, dated December 24, 1974, in the name of Chen et al; 3,881,542, dated May 6, 1975 in the 113~149 RD-10,232 name of Polk et al; 4,052,201, dated October 4, 1977, in the name of Polk et al; 4,059,441, dated November 22, 1977, in the name of Ray et al. and 4,067,732, dated January 10, 1978, in the name of Ray. A survey of metal glass technology is given in the article "Metallic Glasses" by John J. Gilman, appearing in Physics Today, May 1975, pages 46 to 53. Some attempts are being made to exploit the advantages of the properties of these metal tapes, for example, for acoustic devices as shown in United States Letters Patent 3,838,365.
An object of the present invention is to provide a low cost hysteresis machine which employs a coil of amorphous metal tapes as the rotor, the coil being annealed to substantially increase its coercive force.
- Brief Descri tion of the Present Invention P
In accordance with the present invention, a hysteresis machine rotor is made of a coil of amorphous metal tapes. The rotor can be wound in either a single continuous strip or a plurality of parallel overlapping strips, since the machine is a synchronous machine and there are no induced rotor currents.
Several substantially identical coils may be wound side by side.
The amorphous metal tapes are annealed after winding into the coil form,at a suitable temperature for a suitable length of time, up to the point where crystallization of the alloy starts and its coercive force begins to increase. By annealing the tapes, coercive force values ranging from 0.02 to 100 oersteds can be obtained, making the coil useful for hysteresis machine applications.
Brief Description of the Dr~ s FIGURE 1 is a cross-sectional view taken along the axis of a schematically illustrated hysteresis motor fabricated in ~ RD-10,232 accordance with the present invention.
FIGURE 2 is a cross-sectional view of FIGURE 1 taken across the section line 2-2 in FIGURE l.
FIGURE 3 is a cross-sectional view of another embodiment of the hysteresis motor of the present invention.
Detailed Description of the Drawings Referring now to FIGURES 1 and 2, there is schematically illustrated therein a typical hysteresis motor (without housing, supports, or the like) which may be of a general configuration well known in the art. The basic motor structure shown comprises a conventional stator 10 which includes a stack of conventional laminations containing stator winding slots, such as slots 11 and 12, which receive a conventional stator winding 13 operable to produce a rotating field.
A rotor 2Q, described more fully hereinafter, is provided with a shaft 21 which may be carried in suitable bearings 22 and 23 which are fixed with respect to the housing (not shown) supporting rotor 20 and stator 10.
The outer surface of rotor 20 is separated from the inner surface of stator 10 by a fixed radial gap 14.
In accordance with the present invention, rotor 20 is formed of a plurality of coils of an amorphous metal tape having a thickness of about 0.002 inch, each coil comprising a portion of rotor length of about one inch.
Each coil may be formed of a single strip of tape wound on shaft 21 such that its flat sides are parallel to shaft axis 24 and may have an inner diameter of one-half inch and an outer diameter of two inches, so as to comprise 375 turns of 0.002 inch thick tape. If a larger power factor is desired, two or more elongated strips of tape ~1371~ RD-10,232 laid one on top of another 50 as to introduce capacitance into the rotor circuit may be simultaneously wound to form the coil 20. This capacitance introduction by interwinding amorphous metal tapes in a motor is described and claimed in United States patent 4,211,944 issued July 8, 1980 to T.R. Haller and assigned to the present assignee.
FIGURE 1 illustrates five individual coils 30 to 34 which are disposed parallel to one another for forming a rotor having a length greater than the available width of a single tape. Since the amorphous metal tape is coated with an electrically insulating oxide film, side-by-side contact between adjacent ones of coils 30-34 does not result in an electrical path therebetween. Rotor eddy currents are thereby attenuated, resulting in reduced rotor eddy current losses.
Af-ter the rotor 20 has been formed in its coil shape and the ends of the coils have been secured to prevent unraveling, the entire rotor may be annealed in order to increase the coercive force of the rotor.
The coercive force of the metal tapes forming rotor 20 before annealing may be of the order of about 0.01 oersted.
By annealing the tapes, the coercive force can be increased to at least about 0.02 oersted and up to approximately 100 oersteds. As a specific example, when the tape comprises the alloy Fe40Ni40P14B6, we have measured the starting coercive force of the coil to be about 0.015 oersted after the coil is formed. After this coil is annealed for 120 minutes at 390C, we have found that the coercive force of the material increases to about 50 oersteds. Even higher coercive force can be obtained by longer heating and/or by using a higher annealing temperature. Saturation magnetization of this alloy B
1137i45~
RD-l0,232 is about 8,000 gauss. Other alloys using higher or lower saturations could also be used.
Other alloy materials having other saturation magnetiza-tions also experience an increase in coercive force when they are partly crystallized. Thus, the alloy Fe40Ni40B20 has a saturation magnetization of about 10,000 gauss while the alloy Fe80B20 has a saturation magnetization of about 16,000 gauss. These amorphous metal strip alloys, when partially - crystallized, show about the same increase in coercive force -;
as Fe4oNi4opl4B6 The increase in coercive force during annealing is a general phenomenon exhibited by amorphous metal alloys of the ( )80~10(G)20+lo where TM is any of the transition metals and their alloys Fe, Co and Ni, and G is the glass forming atoms usually comprising the metalloids P, B, C, S, Si and Al.
In the embodiment of FIGURE 3, which is a view similar to that shown in FIGURE 2, each of the coils 30-34 in a rotor such as illustrated in FIGURE 1 comprises a pair of amorphous metal tapes 40 and 41 wound together about longitudinal axis 24 such that a flat side of tape 40 contacts a flat side of tape 41, and the flat sides o~ both tapes are parallel to axis 24. The remaining portion of the structure shown in FIGURE 3 is identical to that shown in FIGURE 2, with like numerals designating like components.
Thus, in accordance with the present invention, the -magnetization of a machine rotor is controlled by suitable choice of alloy used in the rotor, and the coercive force of the alloy can be controlled by heat treatment to yield a high quality, low cost rotor structure for a hysteresis machine.
11;~'71~
RD-10 ,232 Although the present invention has been described in connection with only certain preferred features thereof, many variations and modifications will now become apparent to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such variations and modifications as fall within the true spirit of the invention.
Hysteresis machines, such as motors, are well known selt-starting synchronous machines employing the hysteresis properties of the rotor. The driving force is provided by the rotating stator field which m~gnetizes the rotor. If the power supply 1~ frequency remains constant, rotor speed remains constant even if there are changes, within limits, in applied voltage, ambient temperature and attached torque load. Moreover, the motor speed is not affected by manufacturing variations, within pre-determined limits. Consequently, the hysteresis synchronous machine can be used in virtually any applciation requiring synchronous motors.
Torque developed by the motor is proportional to area of the rotor material hysteresis loop, while exciting current for the motor is determined by coercive force of the rotor material. Thus, a coercive force should be selected for a particular hysteresis ~1~7~4~ RD 10,232 machine application which balances exciting current against the available torque for the machine.
The cost of hysteresis motor rotor material is several dollars per pound at the present time.
Use of less expensive material for the hysteresis motor would be desirable. Amorphous metals have recently become available which have good magnetic properties and have a potential cost of one-tenth at of metals now used for hysteresis motors.
Amorphous metals, however, are not available in a form convenient for manufacture of conventional laminated rotors. Thus the metal is in the form of a tape which is about 0.005 to 0.003 inch thick and in widths of up to about 2 inches. The amorphous metal tape also has very low coercive force, of the order of from 0.01 to 0.1 oersteds.
Amorphous metal taps having magnetic properties desired for application to electric machines are disclosed in United States Letters Patents, 3,856,513, dated December 24, 1974, in the name of Chen et al; 3,881,542, dated May 6, 1975 in the 113~149 RD-10,232 name of Polk et al; 4,052,201, dated October 4, 1977, in the name of Polk et al; 4,059,441, dated November 22, 1977, in the name of Ray et al. and 4,067,732, dated January 10, 1978, in the name of Ray. A survey of metal glass technology is given in the article "Metallic Glasses" by John J. Gilman, appearing in Physics Today, May 1975, pages 46 to 53. Some attempts are being made to exploit the advantages of the properties of these metal tapes, for example, for acoustic devices as shown in United States Letters Patent 3,838,365.
An object of the present invention is to provide a low cost hysteresis machine which employs a coil of amorphous metal tapes as the rotor, the coil being annealed to substantially increase its coercive force.
- Brief Descri tion of the Present Invention P
In accordance with the present invention, a hysteresis machine rotor is made of a coil of amorphous metal tapes. The rotor can be wound in either a single continuous strip or a plurality of parallel overlapping strips, since the machine is a synchronous machine and there are no induced rotor currents.
Several substantially identical coils may be wound side by side.
The amorphous metal tapes are annealed after winding into the coil form,at a suitable temperature for a suitable length of time, up to the point where crystallization of the alloy starts and its coercive force begins to increase. By annealing the tapes, coercive force values ranging from 0.02 to 100 oersteds can be obtained, making the coil useful for hysteresis machine applications.
Brief Description of the Dr~ s FIGURE 1 is a cross-sectional view taken along the axis of a schematically illustrated hysteresis motor fabricated in ~ RD-10,232 accordance with the present invention.
FIGURE 2 is a cross-sectional view of FIGURE 1 taken across the section line 2-2 in FIGURE l.
FIGURE 3 is a cross-sectional view of another embodiment of the hysteresis motor of the present invention.
Detailed Description of the Drawings Referring now to FIGURES 1 and 2, there is schematically illustrated therein a typical hysteresis motor (without housing, supports, or the like) which may be of a general configuration well known in the art. The basic motor structure shown comprises a conventional stator 10 which includes a stack of conventional laminations containing stator winding slots, such as slots 11 and 12, which receive a conventional stator winding 13 operable to produce a rotating field.
A rotor 2Q, described more fully hereinafter, is provided with a shaft 21 which may be carried in suitable bearings 22 and 23 which are fixed with respect to the housing (not shown) supporting rotor 20 and stator 10.
The outer surface of rotor 20 is separated from the inner surface of stator 10 by a fixed radial gap 14.
In accordance with the present invention, rotor 20 is formed of a plurality of coils of an amorphous metal tape having a thickness of about 0.002 inch, each coil comprising a portion of rotor length of about one inch.
Each coil may be formed of a single strip of tape wound on shaft 21 such that its flat sides are parallel to shaft axis 24 and may have an inner diameter of one-half inch and an outer diameter of two inches, so as to comprise 375 turns of 0.002 inch thick tape. If a larger power factor is desired, two or more elongated strips of tape ~1371~ RD-10,232 laid one on top of another 50 as to introduce capacitance into the rotor circuit may be simultaneously wound to form the coil 20. This capacitance introduction by interwinding amorphous metal tapes in a motor is described and claimed in United States patent 4,211,944 issued July 8, 1980 to T.R. Haller and assigned to the present assignee.
FIGURE 1 illustrates five individual coils 30 to 34 which are disposed parallel to one another for forming a rotor having a length greater than the available width of a single tape. Since the amorphous metal tape is coated with an electrically insulating oxide film, side-by-side contact between adjacent ones of coils 30-34 does not result in an electrical path therebetween. Rotor eddy currents are thereby attenuated, resulting in reduced rotor eddy current losses.
Af-ter the rotor 20 has been formed in its coil shape and the ends of the coils have been secured to prevent unraveling, the entire rotor may be annealed in order to increase the coercive force of the rotor.
The coercive force of the metal tapes forming rotor 20 before annealing may be of the order of about 0.01 oersted.
By annealing the tapes, the coercive force can be increased to at least about 0.02 oersted and up to approximately 100 oersteds. As a specific example, when the tape comprises the alloy Fe40Ni40P14B6, we have measured the starting coercive force of the coil to be about 0.015 oersted after the coil is formed. After this coil is annealed for 120 minutes at 390C, we have found that the coercive force of the material increases to about 50 oersteds. Even higher coercive force can be obtained by longer heating and/or by using a higher annealing temperature. Saturation magnetization of this alloy B
1137i45~
RD-l0,232 is about 8,000 gauss. Other alloys using higher or lower saturations could also be used.
Other alloy materials having other saturation magnetiza-tions also experience an increase in coercive force when they are partly crystallized. Thus, the alloy Fe40Ni40B20 has a saturation magnetization of about 10,000 gauss while the alloy Fe80B20 has a saturation magnetization of about 16,000 gauss. These amorphous metal strip alloys, when partially - crystallized, show about the same increase in coercive force -;
as Fe4oNi4opl4B6 The increase in coercive force during annealing is a general phenomenon exhibited by amorphous metal alloys of the ( )80~10(G)20+lo where TM is any of the transition metals and their alloys Fe, Co and Ni, and G is the glass forming atoms usually comprising the metalloids P, B, C, S, Si and Al.
In the embodiment of FIGURE 3, which is a view similar to that shown in FIGURE 2, each of the coils 30-34 in a rotor such as illustrated in FIGURE 1 comprises a pair of amorphous metal tapes 40 and 41 wound together about longitudinal axis 24 such that a flat side of tape 40 contacts a flat side of tape 41, and the flat sides o~ both tapes are parallel to axis 24. The remaining portion of the structure shown in FIGURE 3 is identical to that shown in FIGURE 2, with like numerals designating like components.
Thus, in accordance with the present invention, the -magnetization of a machine rotor is controlled by suitable choice of alloy used in the rotor, and the coercive force of the alloy can be controlled by heat treatment to yield a high quality, low cost rotor structure for a hysteresis machine.
11;~'71~
RD-10 ,232 Although the present invention has been described in connection with only certain preferred features thereof, many variations and modifications will now become apparent to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such variations and modifications as fall within the true spirit of the invention.
Claims (6)
1. A hysteresis machine comprising: a stator structure having a central opening with a central axis there-through and having stator winding means for producing a rotating magnetic field about said axis; and a rotor structure positioned within said central opening and rotatable relative to said stator structure about said axis, said rotor structure comprising a plurality of adjacent coils of amorphous metal tape wound substantially concentrically about said axis to collectively define a rotatable magnetic body having the hysteretic properties of a hysteresis machine rotor, each coil consisting of a plurality of turns of tape and each tape having its flat sides parallel to said axis.
2. The machine of claim 1, wherein each of said coils of amorphous metal tape is annealed and exhibits a coercive force greater than about 0.02 oersted.
3. The machine of claim 1, wherein said rotor structure includes a rotatable shaft extending coaxially with said axis, said shaft being fixed to said coils.
4. The machine of claim 3, wherein each of said coils is annealed and exhibits a coercive force in the range of about 0.02 oersted to about 100 oersteds.
5. The machine of claim 4, wherein said amorphous metal tape is an alloy of the general class (TM)80?10(G)20?10 wherein (TM) comprises one of the group consisting of the transition metals and their alloys and (G) comprises one of the group consisting of the glass forming elements including the metalloids P, B, C, S, Si and Al.
6. The machine of claim 1, 4 or 5, wherein each of said coils of amorphous metal tape comprises a plurality of individual tapes, each of said individual tapes having a flat RD-10,222
6. The machine of claim 1, 4 or 5, wherein each of said coils of amorphous metal tape comprises a plurality of individual tapes, each of said individual tapes having a flat RD-10,222
Claim 6 continued:
side in contact with a flat side of another of said individual tapes.
side in contact with a flat side of another of said individual tapes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000331279A CA1137149A (en) | 1979-07-06 | 1979-07-06 | Hysteresis motor having amorphous metal rotor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000331279A CA1137149A (en) | 1979-07-06 | 1979-07-06 | Hysteresis motor having amorphous metal rotor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1137149A true CA1137149A (en) | 1982-12-07 |
Family
ID=4114625
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000331279A Expired CA1137149A (en) | 1979-07-06 | 1979-07-06 | Hysteresis motor having amorphous metal rotor |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1137149A (en) |
-
1979
- 1979-07-06 CA CA000331279A patent/CA1137149A/en not_active Expired
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