US3358381A - Spin dryer having a shaded-pole motor - Google Patents

Spin dryer having a shaded-pole motor Download PDF

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Publication number
US3358381A
US3358381A US475341A US47534165A US3358381A US 3358381 A US3358381 A US 3358381A US 475341 A US475341 A US 475341A US 47534165 A US47534165 A US 47534165A US 3358381 A US3358381 A US 3358381A
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United States
Prior art keywords
pole
motor
shaded
torque
dryer
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Expired - Lifetime
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US475341A
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English (en)
Inventor
Sowa Werner
Tillner Siegfried
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Licentia Patent Verwaltungs GmbH
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Licentia Patent Verwaltungs GmbH
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K17/00—Asynchronous induction motors; Asynchronous induction generators
    • H02K17/02—Asynchronous induction motors
    • H02K17/04—Asynchronous induction motors for single phase current
    • H02K17/10—Motors with auxiliary phase obtained by split-pole carrying short-circuited windings
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
    • D06F49/00—Domestic spin-dryers or similar spin-dryers not suitable for industrial use
    • D06F49/04—Bowl drive
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
    • H02K7/14—Structural association with mechanical loads, e.g. with hand-held machine tools or fans

Definitions

  • ABSTRACT OF THE DISCLOSURE A household laundry spin dryer composed of a rotatable drum mounted directly on the vertically-oriented shaft of a drive motor, the drum motor assembly being supported by a spring assembly, the motor being of the shaded pole type and serving to impart an increased acceleration to the drum over the lower portion of its speed range due to the fact that the motor is constructed so that its torque-speed characteristic is increased in this lower speed range at the expense of the motor breakdown torque, which occurs at the upper portion of the assembly speed range.
  • the present invention relates generally to household laundry spin dryers, and, more particularly, to a simplification and an improvement of such a device which has centrifugal speeds in the range of 1350 to 3000 revolutions per minute (r.p.m.).
  • Household laundry spin dryers are spin dryers which can be set up free standing and have a loading capacity of 2 to 5 kilograms of dry clothing.
  • the centrifugal drum is directly or indirectly mounted on the motor shaft and the assembly or unit formed by the motor and the centrifugal drum totical direction.
  • Two and four-pole Single phase A.C. motors usually of the capacitor type are mainly used for driving such devices.
  • a simple one-phase A.C. motor having a short-circuited inductive or a low starting and accelerating torque for example, table fans, heating fans, simple record players, and similar devices.
  • Shaded-pole motors having the power necessary for meeting the coming-to-speed time requirements not only have a relatively low starting torque of below 0.5 of the rated or nominal torque, but also at about one third of the synchronous speed there is a pronounced reduction in the torque which is particularly caused by a third field harmonic which moves in the direction of rotation.
  • the moment of inertia or flywheel moment increases considerably because of the outward displacement of the Wet laundry toward the walls of the drum.
  • the motor-spin dryer assembly at this point passes through its critical rotational speed which is caused by the imbalance of the laundry. Because of this, considerable vibrations of the motor and the drum are caused, depending on the amount of imbalance and the time it takes to pass through its critical speed. The result of this is that the torque requirement for the spin dryer increases to exceed the torque provided by the motor, that is, the spin dryer does not increase its speed.
  • the two-pole shaded-pole motor permits its power rating to such an extent and to and in which the usual dip in speed of the motor is significantly obviated.
  • a motor-centrifugal drum assembly is elastically suspended and mounted with its axis in the vertical direction.
  • the motor is a shaded-pole motor in which above all the torque-speed characteristic is raised in the lower r.p.m. range at the expense of the break-down torque to such an extent that the integral of the torque speed curve is by suitable construction of the short-circuited winding and of the rotor resistance in conjunction with high saturation.
  • FIGURE 1 is a schematic partial sectional view illustrating the basic structure or" the spin dryer of the present invention.
  • FIGURE 2 is an elevational view of one of the stacked laminations of the stator of the two-pole drive motor.
  • FIGURE 1 it can be seen from FIGURE 1 that the motor 3 is suspended by means of spring members 4 from the bottom of the housing 1 of the spin dryer.
  • the centrifugal drum 6 is mounted directly on the shaft of the motor.
  • the motor is ventilated by two finned rotors 7 and 8.
  • the assembly which comprises the motor and centrifugal drum is mounted so that it can swing or vibrate in all directions.
  • the stator of the two-pole shaded-pole motor is constructed of a stack of laminations each of which includes a generally rectangular yoke frame 9 and the ole laminations or pole stars 1%) which are inserted into the frame.
  • the concentric field winding (not shown) is disposed about the pole shoes 11 and 12.
  • the width 13 of the pole shoe is about one half of the pole lamination width 14.
  • This pole lamination width 14 is about 1.1 times as large as the diameter 15 of the rotor opening.
  • the restriction or narrow magnetic path which is provided in the connection-which represents the leakage web 16between the main pole portion 17 and the shaded pole portion 18 of the other pole, is provided by the slots 19 and 2% which open outwardly.
  • the tip 21 of the main pole is tapered from the main pole portion.
  • This tapering is provided by a circular are 22 having its center 23 on the pole axis and at a distance of 1/6 of the rotor opening diameter from the center of the rotor opening and having a radius 24 which is one half of the width of the pole lamination.
  • the length of this are from the startingpoint of the tip 21 of the main pole to the narrowest restriction is about four times the width of the starting point 25.
  • This arc subtends an angle .of about 97.
  • the slot 19 is disposed at an angle of 28 relative to the median perpendicular to the pole axis whereas the smaller slot is at an angle of 16 with respect thereto.
  • a zone for the narrow magnetic path is provided which corresponds to an arc of 12.
  • the split pole slot 26 which is adjacent to the pole axis is at an angle of 23 relative to the pole axis, and that the starting point of the tip of the main pole is disposed at an angle of 21 relative to the pole axis, then it can be seen that the arc subtended by the main pole is 129, the are for the shaded pole is 39, and the are for the zone of the narrow magnetic path is 12.
  • the point at which the breakdown torque occurs is of less importance than the entire acceleration or coming-tospeed curve of the motor and this is particularly the case in the lower r.p.m; range because of the exceptionally steep rise of the speed which is required when the device passes through the critical speed.
  • the resistance of the short-circuited auxiliary pole-the short-circuited winding must be decreased and the resistance of the squirrel cage in the rotor has to be increased and the motor has to have higher saturation.
  • a two-pole shaded-pole motor having distinctly defined poles is advantageously used in the present invention because of its higher r.p.m.
  • the stack of laminations of the stator as has been seen from the above, includes a substantially rectangular yoke frame having a pole lamination inserted into it or a so-called pole star. This type of construction is most suitable for the embodiment of a two-pole shadedpole motor having those characteristics F output.
  • the magnetic flux for the invention which permit the. needed increase of the power rating and the adjustment of the torque-speed curve. In addition to this, they are simple and economical.
  • the amount of metal laminations required is smaller than when they are round-cut and the paths of the lines of force are'the shortest.
  • the scattering conditions become very critical because of the higher number of ampere turns. They are partly responsible for the limitation of the power rating and therefore special attention must be given to the scattering paths.
  • Critical scattering conditions occur at the scattering webs which are the magnetic connecting straps from the main pole to the shaded pole which is adjacent to it.
  • thefiux from the main pole portion to the shaded pole portion of the neighboring pole becomes too great, and has to be limited by a narrowing or restriction or a raising of the magnetic narrow path.
  • This restriction can be obtained by making holes, or more advantageously by providing slots or grooves, in the tip of the shaded pole.
  • two or more slots are made which open outwardly.
  • the Zone of the narrowing must not extend up 'to median perpendicular to the pole axis for otherwise the are for the main pole would become too small.
  • the are for the shaded pole is thus smaller than 50.
  • the favorable position and size of the narrow magnetic path which is provided by the constriction contributes to a lessening of the harmonic induction distribution in the air gap.
  • the air gap between the back of the main pole and yoke has to be made wider with respect to motors having smaller which would flow as a result of the high saturation would be a real loss since it does not contribute to the generation of torque as does the scattering flux from one pole tip to the other. Therefore, the distance betwen the yoke and the back of the pole, that is, the back of the pole tip, has to be relatively large. In accordance with the invention, it should not be smaller than one tenth of the diameter of the rotor opening. The necessary continuous tapering of the pole tip of the main pole also satisfies this requirement. The approximation of the field strength distribution in the air gap to the sinusoidal form which is obtained and especially the third harmonic, is suppressed. This harmonic causes the dip in the accelerating curve.
  • this tapering is provided by a circular are which has its center on the axis of the pole and at a distance from the center of the rotor opening which is about of the diameter of the rotor opening. It has a radius which is equal to /2 of the width of the pole laminations and this width is about 1.1 times as large as the diameter of the rotor opening.
  • the pole width is about one half of the diameter of the rotor opening and provides a certain width for the starting point of the pole tip at the main pole.
  • the length of the pole are from its starting point to the constriction is arranged to be about four times as large as the width of the starting point. This arc subtends an angle of 97.
  • the are of the shaded pole is thereby reduced in favor of the arcof the main pole and the power loss is thus reduced.
  • An arc subtending an angle of less than 50 is thus provided for the shaded pole.
  • the power loss of the shaded pole is further reduced by a conductor cross section of the shaded pole windings which is small compared to those of smaller motors.
  • the shaded pole slot which is adjacent to the axis of the pole is disposedsubstantially at the point where the tip of the pole starts.
  • a sufficient phase displacement is obtained by such an arrangement as are considerably great starting and acceleration torques.
  • a spin dryer comprising,
  • a shaded pole motor having a drive shaft extending vertically therefrom, said motor including a rotor and a short circuited winding, said short circuited winding and the resistance of said rotor, in conjunction with high saturation being arranged so that the torque-speed characteristic is raised in the low speed range and at the expense of the breakdown torque to such an extent that the integral of the torquespeed characteristic is substantially equal to the integral of the torque-speed characteristic of a motor which is constructed to have a maximum breakdown torque;
  • centrifugal drum mounted on said drive shaft and defining an assembly therewith;
  • the tip of the main pole is continuously tapered from its starting point to the median perpendicular to the pole axis.
  • each lamination is provided with a rotor opening, the tapering being provided by a circular arc having its center on the pole axis at a distance of about of the rotor opening diameter from the center of such opening and a radius which is about one half of the width of the pole lamination.
  • each lamination defines two main poles and two auxiliary poles, a connection strip disposed between the tip of each main pole and the tip of the auxiliary pole associated with the other main pole, said connection strip providing a constriction and a narrow magnetic path beyond the median perpendicular to the pole axis.
  • a dryer as defined in claim 9 wherein a slot is provided to define each shaded pole, said outwardly opening slots being of different size and depth with the larger and deeper of the slots being disposed closer to the shaded pole slots.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Textile Engineering (AREA)
  • Iron Core Of Rotating Electric Machines (AREA)
  • Detail Structures Of Washing Machines And Dryers (AREA)
  • Manufacture And Refinement Of Metals (AREA)
US475341A 1964-07-29 1965-07-28 Spin dryer having a shaded-pole motor Expired - Lifetime US3358381A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DEL0048407 1964-07-29

Publications (1)

Publication Number Publication Date
US3358381A true US3358381A (en) 1967-12-19

Family

ID=7272470

Family Applications (1)

Application Number Title Priority Date Filing Date
US475341A Expired - Lifetime US3358381A (en) 1964-07-29 1965-07-28 Spin dryer having a shaded-pole motor

Country Status (7)

Country Link
US (1) US3358381A (enrdf_load_stackoverflow)
AT (1) AT270559B (enrdf_load_stackoverflow)
BE (1) BE667597A (enrdf_load_stackoverflow)
DE (1) DE1488208B2 (enrdf_load_stackoverflow)
NL (1) NL6509717A (enrdf_load_stackoverflow)
NO (1) NO118906B (enrdf_load_stackoverflow)
SE (1) SE330412B (enrdf_load_stackoverflow)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3824701A (en) * 1972-09-05 1974-07-23 B Norquist Portable centrifugal drier for small articles
US4712035A (en) * 1985-11-12 1987-12-08 General Electric Company Salient pole core and salient pole electronically commutated motor
US4835839A (en) * 1985-11-12 1989-06-06 General Electric Company Method of fabricating a salient pole electronically commutated motor
US5619871A (en) * 1985-11-12 1997-04-15 General Electric Company Laundry machine
US5918360A (en) * 1985-11-12 1999-07-06 General Electric Company Method of fabricating a salient pole electronically commutated motor
USRE37576E1 (en) 1993-02-22 2002-03-12 General Electric Company Single phase motor with positive torque parking positions

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3004085C2 (de) * 1980-02-05 1983-07-14 Robert Thomas Metall- und Elektrowerke, 5908 Neunkirchen Wäscheschleuder mit drehzahlumschaltbarem Antrieb
DE102006042968A1 (de) * 2006-09-13 2008-03-27 Schaeffler Kg Antriebsvorrichtung für Separatoren

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1071956A (en) * 1910-07-27 1913-09-02 John T Psarski Centrifugal drier.
GB751554A (en) * 1954-02-06 1956-06-27 Emailleerfabriek De Ijsel Nv Improvements in centrifrugal drying machines
US2827583A (en) * 1954-10-26 1958-03-18 Universal Electric Corp Shaded pole motor
GB956610A (en) * 1960-10-05 1964-04-29 Licentia Gmbh A spin dryer

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1071956A (en) * 1910-07-27 1913-09-02 John T Psarski Centrifugal drier.
GB751554A (en) * 1954-02-06 1956-06-27 Emailleerfabriek De Ijsel Nv Improvements in centrifrugal drying machines
US2827583A (en) * 1954-10-26 1958-03-18 Universal Electric Corp Shaded pole motor
GB956610A (en) * 1960-10-05 1964-04-29 Licentia Gmbh A spin dryer

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3824701A (en) * 1972-09-05 1974-07-23 B Norquist Portable centrifugal drier for small articles
US4712035A (en) * 1985-11-12 1987-12-08 General Electric Company Salient pole core and salient pole electronically commutated motor
US4835839A (en) * 1985-11-12 1989-06-06 General Electric Company Method of fabricating a salient pole electronically commutated motor
US5619871A (en) * 1985-11-12 1997-04-15 General Electric Company Laundry machine
US5918360A (en) * 1985-11-12 1999-07-06 General Electric Company Method of fabricating a salient pole electronically commutated motor
USRE37576E1 (en) 1993-02-22 2002-03-12 General Electric Company Single phase motor with positive torque parking positions

Also Published As

Publication number Publication date
AT270559B (de) 1969-05-12
DE1488208A1 (de) 1970-10-01
DE1488208B2 (de) 1971-06-03
BE667597A (enrdf_load_stackoverflow) 1965-11-16
SE330412B (enrdf_load_stackoverflow) 1970-11-16
NO118906B (enrdf_load_stackoverflow) 1970-03-02
NL6509717A (enrdf_load_stackoverflow) 1966-01-31

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