Single-phase shaded pole induction motor, convertible to permanent magnet motor

Abstract

The present invention refers to a shaded-pole single-phase motor convertible into a permanent magnet motor of the type that comprises a front casing, a stator element, a rotor element, a plurality of windings placed over the protruding poles of the stator element, and a rear casing, wherein the stator element presents a square-shape configuration with the four protruding poles rotated 45? relative to the horizontal and vertical symmetry axes in order to be aligned with the four corners of the stator element. The stator new configuration enables optimizing the use of lamination material during manufacturing and assembling the sheet packages of the stator element and rotor element; furthermore, the protruding poles, by being rotated 45? in the stator element, enable a reduction of electric losses in its windings and a decrease in the operative temperature of both the stator element and the rotor element, which enables an increase of the motor operation efficiency. Similarly, the reduction of the operative temperature of the stator element allows the use of plastic materials for its components.

Claims

1. A shaded-pole single-phase induction motor convertible into a permanent magnet motor of the type that comprises: a front casing, a stator element, a rotor element, a plurality of windings placed over the protruding poles of the stator element, and a rear casing, wherein the stator element presents a square configuration with the four protruding poles rotated by 45? relative to the horizontal and vertical symmetry axes in order to be aligned with the four corners of the stator element, the stator element configuration providing a free area for housing the windings, wherein the motor comprises insert elements which couple the stator element in each of the four exterior sides of the stator element, and wherein said insert elements are formed by punching waste excess material obtained after punching the free area for housing the windings.

2. The shaded-pole single-phase induction motor according to claim 1, wherein the free area for housing the windings is of at least 500 mm.sup.2.

3. The shaded-pole single-phase induction motor according to claim 1, wherein the free area for housing the windings is of 557.84 mm.sup.2.

4. The shaded-pole single-phase induction motor according to claim 1, wherein the insert elements are assembled in each of the four exterior sides of the stator by assembly elements located on the sides of the insert elements.

5. The shaded-pole single-phase induction motor according to claim 4, wherein the assembly elements are of the tongue and groove type.

6. The shaded-pole single-phase induction motor according to claim 1, wherein the insert elements include a plurality of undulations on their external side face.

7. The shaded-pole single-phase induction motor according to claim 1, wherein the insert elements have a smooth external side face.

8. The shaded-pole single-phase induction motor according to claim 1, wherein the stator element includes at least two punched holes in two of its adjacent corners which work as a support base, one in each corner, to insert at least two fastening elements so as to be able to fasten the motor.

9. The shaded-pole single-phase induction motor according to claim 8, wherein the fastening elements are screws.

10. The shaded-pole single-phase induction motor according to claim 1, wherein the configuration of the stator element further provides a greater free space for the rotor element.

11. The shaded-pole single-phase induction motor according to claim 10, wherein the configuration of the stator element admits such a rolling diameter of the rotor element that it allows greater motor efficiency.

12. The shaded-pole single-phase induction motor according to claim 11, wherein the free space for the rotor element is of at least 30 mm.sup.2.

13. The shaded-pole single-phase induction motor according to claim 10, wherein the rotor element is of the squirrel cage type comprising a plurality of conductive bars, a pair of rings short-circuited with the plurality of conductive bars, a support body and an arrow element crossing the support body through the center.

14. The shaded-pole single-phase induction motor according to claim 13, wherein the configuration of the stator element increases an area of free spaces for the rotor conductive bars, which allows greater motor efficiency.

15. The shaded-pole single-phase induction motor according to claim 10, wherein the rotor element is a permanent magnet rotor element.

16. The shaded-pole single-phase induction motor according to claim 15, wherein when the motor operates with the permanent magnet rotor element, it includes a front isolating jacket including a cavity to house a Hall Effect sensor element.

17. The shaded-pole single-phase induction motor according to claim 16, wherein the Hall Effect sensor element is located in an angular position at a variable gap range up to 45? of advancement relative to the magnetic pole.

18. A shaded-pole single-phase induction motor according to claim 15, wherein the Hall Effect sensor element is advanced about 17? relative to the magnetic pole.

19. The shaded-pole single-phase induction motor according to claim 10, wherein it includes a pair of isolating front and rear jackets disposed between the stator element and the front and rear casings respectively.

20. The shaded-pole single-phase induction motor according to claim 19, wherein the isolating jackets further serve to contain and shape the winding.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The novel aspects considered characteristic of the present invention will be particularly established in the appended claims. However, the advantages and other objects thereof will be better understood by the following detailed description of a specific embodiment when reference to the appended drawings is made, in which:

(2) FIG. 1 is a front perspective view of a shaded pole induction motor convertible into a permanent magnet motor, constructed according to the principles of the present invention.

(3) FIG. 2 is a front perspective view of the induction motor assembly of FIG. 1 without the front casing and without the rotor.

(4) FIG. 3 is a perspective view of the inner portion of the induction motor front casing of FIG. 1 with the rotor assembled thereon.

(5) FIG. 4 is a front view of the induction motor of FIG. 1 without both casings (front and rear) and without the thermoplastic isolating jackets, in order to show the inner details of punching, assembly and shade coils of the stator element as well as the squirrel-cage type rotor element.

(6) FIG. 5 is a front view of an additional embodiment of the electric motor showed in FIG. 1 without both casings (front and rear), without the thermoplastic isolating jackets and without the shade coils, in order to show the inner details of punching and assembly of both the stator element and the permanent magnet type rotor element.

(7) FIG. 6A is a plan view of a layoff for punching the induction motor squirrel-cage type rotor element and stator element of FIG. 1 where the inner punching details are showed.

(8) FIG. 6B is a plan view of an additional embodiment of the layoff for punching the induction motor squirrel-cage type rotor element and stator element showed in FIG. 6A.

(9) FIG. 7 is a plan view of a layoff for punching the permanent magnet motor rotor element and stator element of FIG. 5 where the inner punching details are showed.

(10) FIG. 8 is an exploded view of the electric motor stator element of the present invention once it has been punched and is ready for being assembled.

(11) FIG. 9A is a plan view of the pockets where the windings are housed, where inner details of the previous art and details of the present invention are showed for shape and size comparison.

(12) FIG. 9B is a plan view of the pockets shape and size where the rotor bars are housed, in which details of the previous art and details of the present invention are showed.

(13) FIG. 9C is a plan view of the lamination punching of a square shape stator element of an induction motor of the previous art.

(14) FIG. 9D is a plan view to show the punching of a round stator element lamination of a induction motor of the previous art.

(15) FIG. 10 is an exploded view of the stator and the top and bottom isolating jackets shown in FIG. 2.

(16) FIG. 11 is a top perspective view of a partial cut-out of the installation of a Hall Effect sensor element in the top isolating jacket.

(17) FIG. 12 is a perspective view of a squirrel-cage type rotor used in the induction motor of the present invention.

(18) FIG. 13A is a perspective view of a permanent magnet type rotor used in the induction motor of the present invention.

(19) FIG. 13B is an exploded view of the permanent magnet type rotor showed in FIG. 13A.

(20) FIG. 14 shows the results of energy consumption measurement test to which a motor according to the principles of the present invention (ROBEL Q9-580-690-27-312) was subjected, comparing it against the results of the energy consumption measurement test to which a motor of the current art (ELCO NU9-20-2) was subjected.

(21) FIG. 15 shows the results of angular velocity measurement test to which the ROBEL Q9-580-690-27-312 motor was subjected, comparing it against the results of the angular velocity measurement test to which the ELCO NU9-20-2 motor was subjected.

(22) FIG. 16 shows the results of energy consumption measurement test to which a motor according to the principles of the present invention (ROBEL ECMQ16WO) was subjected, comparing it against the results of the energy consumption measurement test to which a motor of the current art (A.O. SMITH E128044) was subjected.

(23) FIG. 17 shows the results of angular velocity measurement test to which the ROBEL ECMQ16WO motor was subjected, comparing it against the results of the angular velocity measurement test to which the A.O. SMITH E128044 motor was subjected.

DETAILED DESCRIPTION OF THE INVENTION

(24) Making reference to the accompanying drawings and further particularly to FIGS. 1 to 3 thereof, they show a shaded pole induction motor 100 convertible into a permanent magnet motor, constructed according to a particularly preferred embodiment of the present invention, which must be considered as illustrative but not limiting thereof, in which said shaded pole induction motor is a single-phase electric induction motor of fractional power with four shaded protruding poles, which comprises a front casing 101; a stator element 102; a rotor element 103; a pair of front 104 and rear 114 isolating jackets provided between the stator element 102 and the front 101 and rear 106 casings, respectively; a plurality of windings 105 placed over the four protruding poles of the stator element 102; and a rear casing 106.

(25) In FIG. 4 the novel configuration of the stator element 102 of the present invention is showed, which is characterized for showing a square shape lamination and with the stator element 102 protruding poles 107 being rotated by 45? relative to the horizontal A-A symmetry axis and vertical B-B symmetry axis. As can be seen, this configuration is novel in relation to the traditional position of the protruding poles of the previous art, which is precisely located over the A-A and B-B symmetry axes as can be observed in FIGS. 9C and 9D, where the configurations of the stators of the previous art are shown. The new configuration allows optimizing the use of the material of electric grad steel sheet during the manufacture and assembling of sheets packages of the stator element 102 and rotor element 103.

(26) This position change by a 45? rotation allows to place the protruding poles 107 of the stator element 102 over the C-C and D-D diagonal axes crossing by exactly 45? the A-A horizontal and B-B vertical symmetry axes of the square shaped lamination.

(27) Upon alignment of said protruding poles 107 toward the corners 108 of the stator element 102, the new design of the present invention allows for the punched pockets 109 to provide a bigger space to house the windings 105.

(28) Providing a bigger area allows saving electric energy according to the principle of minimizing the Joule Effect W=I.sup.2?R, due to the fact that a smaller caliber magnet wire may be used; and, therefore, with a bigger conductive area; since it is known, the bigger the area of a conductor is, the smaller resistance to electric current flow will have and consequently, the electric losses by Joule Effect will be reduced as well. Additionally, the possibility to increase the winding loops or turns is simultaneously obtained, which allows performing a better cost-benefit and efficacy balance to select the best winding according to the motor requirements; as well as to select the optimal coiling parameters.

(29) The lamination of the rotor element 103 of the present invention is characterized for having two embodiments, the first embodiment is shown in FIGS. 4 and 12 which correspond to squirrel-cage type rotor element 103 consisting of a plurality of conductive bars 117, a pair of short-circuited rings 118 placed with the plurality of conductive bars 117, a support body 119 and an arrow element 120 crossing the support body 119 by its center, both elements being firmly joined to one another. The rotor element 103 rotates while the motor operates due to the principle of electric currents induction induced by the magnetic field of the stator element 102, with a torque being thus generated.

(30) The second embodiment is shown in FIGS. 5, 13A and 13B, which corresponds to a permanent magnet type rotor element 103 consisting of a permanent magnet ring 121, a support body or sheet 122 being inserted into the permanent magnet ring 121 and an arrow element 124 crossing the support body 122 by its center. The support body 122 further includes a plurality of striations 123 throughout its circumference, so as to be able to couple with the permanent magnet ring 121.

(31) Referring to FIGS. 6A, 6B and 7, they show layoffs for punching the stator element 102 and laminations 119 and 122 of the electric motor rotor element 103 both in its squirrel-cage type rotor embodiment (FIGS. 6A and 6B), and in its permanent magnet type rotor embodiment (FIG. 7) respectively.

(32) The layoff design, being squared and with a 45? rotation of the protruding poles 107 of the stator element 102, relative to the horizontal symmetry axis A-A and the vertical symmetry axis B-B, allows for optimization of the spaces and making the most of the remaining material for punching additional elements for the stator element 102.

(33) The new design allows the punched pockets 109 to provide greater space for the windings 105 to lodge (see FIGS. 4 and 7); in addition, some of the waste excess material from the electric steel sheet remains, and is used for punching an insert element 110, which couples with the stator element 102. The insert element 110 is assembled with the stator 102 by assembly elements 111, preferably of the tongue and groove type (see FIG. 8), in each of the four exterior sides of the stator 102, thus reinforcing and improving the magnetic circuit of said sides.

(34) The above mentioned layoff design for punching allows, at the time of punching and assembling the stator element 102, obtaining an increase of the conductive cross-sectional area on the sides of said stator element 102, so as to improve conduction of the magnetic flow in said stator, while obtaining cost cuts in materials during manufacture of about 30% in steel sheet, with maximum optimization of the sheet, which directly reflects on production costs.

(35) Regarding FIG. 6B, it shows an additional embodiment of the layoff for punching the stator element 102 and the electric motor rotor element 103. This layoff design is very similar to the one in FIGS. 6A and 7, but unlike these, insert elements 110 are integrated to the stator element body 102, thereby simplifying progressive punching.

(36) In this embodiment, while the waste obtained by the space gained by a 45? rotation of the poles is not exploited, using C-C and D-D axes considerably simplifies punching.

(37) On the other hand, as mentioned above, in FIG. 8 the way that insert elements 110 and stator element 102 are assembled once they have been manufactured can be seen; as well as the manner by which punched pockets 109 are ready to receive the corresponding windings.

(38) Likewise, insert elements 110 are designed with a plurality of undulations 112 on their external side face, which, when the motor is operating normally, are exposed to the environment, which allows increasing heat dissipation in the stator element 102, but mainly it allows decreasing magnetic circuit reluctance, obtaining a better magnetic flow, whereby losses by parasite currents or Eddy currents in the steel sheet are reduced; in addition, as mentioned above, there is better heat dissipation due to an increase of the heat dissipation area in undulated zones 112, which work as heat exchanging fins, with no additional material cost, thereby causing a working temperature reduction of the stator 102 and windings 105, which also translates into a reduction of electrical losses due to the working temperature decrease in said magnet wire windings 105.

(39) As can be seen, novel configuration of stator element 102 allows obtaining a lower operative temperature in the motor, which gives the possibility of augmenting the rotor element 103 diameter. Having a greater diameter compared to motors from the previous art, the rotor element 103 also presents an operative temperature reduction and, as a consequence, there are less losses due to the Joule effect W=I.sup.2?R in said rotor element 103.

(40) As the motor becomes more efficient, the wasted heat decreases and, therefore, the temperature difference between the motor and environment air temperature also decreases (temperature gradient). By having a colder working temperature both in the copper winding 105 of the stator element 102 and in the conductive bars of the rotor element 103, a lower ohmic resistance of the windings is achieved, since as it is well known, conductive materials change their ohmic resistance according to temperature, the higher the temperature, the higher copper and aluminum ohmic resistance will be, whereby the motor of the present invention, by not wasting electric energy which turns into heat, will have less losses caused by the Joule effect.

(41) On the other hand, the stator element 102 of the present invention also includes as an additional characteristic that its configuration presents at least two punched holes 113 in two of its adjacent corners which work as a support base, one in each corner, to insert at least two fastening elements, preferably a pair of bolts so as to fasten the motor. This improvement in the stator 102 assembly enables the fastening elements to fix on a side face of the stator element 102, being able to be inserted therein, even when the motor is completely assembled; which enables choosing the option whether to use this type of fasteners to fix the motor to a base when required, thereby achieving a cost cut in fastening elements when they are not necessary. All the more, with this additional characteristic it is possible to substitute a conventional electric motor with an induction motor of the present invention in a system or machinery without the need of performing any modifications.

(42) Regarding FIG. 9A, it shows configurations presented by free areas in pockets to place the winding in the conventional stator elements of the previous art, contrasting them against the free area obtained with the new punching configuration for the stator element 102 of the present invention.

(43) Free area ? corresponds to a squared lamination stator from the previous art with a free area for the winding of 406.62 mm.sup.2.

(44) Free area ? corresponds to a round lamination stator from the previous art with a free area for the winding of 338.18 mm.sup.2.

(45) Free area ? corresponds to a squared lamination stator of the present invention, with protruding poles rotated 45? relative to horizontal and vertical symmetry axes, with a free area for the winding of 557.84 mm.sup.2.

(46) As can be observed, the novel configuration of the stator element 102 substantially increments the free area for the winding (section area useful to house the winding), in contrast with conventional stator configurations from the previous art, as can be seen in Table I:

(47) TABLE-US-00001 TABLE I AREA INCREMENT OF SECTION AREA USEFUL FOR WINDING BY 45? ROTATION OF PROTRUDING POLES AREA INCREMENT OF FREE AREA (III) RELATIVE TO A (I) (FIG. 9A) OR (II) IN (%) I).- Conventional round ? = 338.18 mm.sup.2 lamination (standard average in the market with size 3.3 Frame) II).- Conventional ? = 406.62 mm.sup.2 squared lamination (standard average in the market with size 3.3 Frame) III).- New lamination of ? = 557.84 mm.sup.2 (I) + 64.95% the invention (size 3.3 (II) + 37.18% Frame)

(48) Development of the stator element 102 of the present invention, that is to say, with protruding poles rotated 45? relative to horizontal and vertical symmetry axes, compared against the conventional stator from the previous art, either in squared punching or round punching, in addition to the increment in the section area useful for winding, has allowed to obtain unique and substantial benefits: 1. Waste generated in the corners during previous-art punching is harnessed; also, by rotating the position of the poles in the lamination puncher by 45?, the benefit of incrementing the space where the loops or coils of magnet wire is obtained, which allows for a better caliber selection of the magnet wire and an optimal selection of the number of turns in the poles loops. 2. Waste generated during the punching operation of pocket 109 for winding is harnessed. It is important to mention that this waste is turned into the insert element 110, which is added to the stator lamination as an element which helps in heat dissipation and magnetic flow conduction, benefiting the motor itself. 3. The stator element 102 with protruding poles characteristics can be used in the motor version with electronically switched permanent magnet type rotor. 4. It is a single-phase motor of shaded poles with better efficiency characteristics, in comparison with previous art motors of its type which are currently in the market.

(49) On the other hand, in FIG. 9B configurations presented by the free section area for conductive bars 117 of the previous art squirrel cage type rotor are shown, compared against the free section area for the rotor bars which is obtained with the new punching configuration for the rotor element 103 of the present invention. It can also be seen that for an electric motor with similar characteristics and the same power, due to energy efficiency of the stator element 102, a rotor element 103 of greater diameter which possesses less electrical losses can be employed.

(50) Free area ? corresponds to a squirrel-cage type rotor, either of round lamination or squared lamination from the previous art, with a free area for the rotor bars of 22.5906 mm.sup.2 and a diameter of 4.4249 cm.

(51) Free area ? corresponds to a squirrel-cage type rotor of squared lamination according to the principles of the present invention, with a free area for the rotor bars of 34.356 mm.sup.2 and a diameter of 4.8654 cm.

(52) As can be seen, the novel configuration of the rotor element 103 substantially increments (up to 54%) the free area for the rotor bars, just as it is shown in FIG. 9B and in Table II, in addition to augmenting the external diameter of the rotor:

(53) TABLE-US-00002 TABLE II INCREMENT IN SECTION AREA FOR ROTOR BARS AREA INCREMENT BETWEEN (I) FREE AREA AND (II) FOR CONDUCTIVE (FIG. 9B) BARS OF THE ROTOR (%) I).- Previous art ? = 22.59 mm.sup.2 rotor lamination II).- New rotor ? = 34.35 mm.sup.2 +54% lamination

(54) A very important aspect to consider is the improvement obtained in the induction motor efficiency of the present invention, by augmenting the area of the free spaces 8 for conductive bars of the rotor element 103 of squirrel cage type, without growing standard motor size, but actually incrementing the space (diameter) for the rotor.

(55) By having a bigger free space 8 in the rotor element 103, the cross-section area of conductive bars 117 of the squirrel cage can be substantially augmented, thereby reducing their ohmic resistance and therefore the losses due to the Joule effect W=I.sup.2?R. In FIG. 9B it is observed that the free space e for the conductive bar 117 of the rotor of the present invention has an area of 34.356 mm.sup.2, while the free space ? for the conductive bar 117 of the previous art conventional rotor only has 22.56 mm.sup.2, namely, the rotor element 103 of the present invention has 52% more passage area relative to the previous art passage area.

(56) Referring to FIGS. 9C and 9D, they show the puncher for lamination of two previous art different induction motors, in FIG. 9C a squared stator element 102 is shown and in FIG. 9D a round stator element 102 is shown, where it can be seen that the waste material generated by punching both stators from a single squared sheet of electric grade steel is not harnessed into some other motor component. The reduction in the free area 109 to place windings 105 of the stator element 102 while the protruding poles 107 are oriented can also be seen, precisely over the horizontal A-A and vertical B-B symmetry axes.

(57) Regarding FIG. 10, it shows frontal 104 and posterior 114 isolating jackets, manufactured with an isolating material, preferably with a thermoplastic material; the jacket 104 being disposed in the frontal part of the stator element 102; and the jacket 114 being disposed in the posterior part of the stator 102. Said isolating jackets further serve to contain and shape the winding, which allows achieving a loop or half turn possible minimum length. Additionally, the frontal isolating jacket 104 includes a pocket 115 to house a sensor element 116 of Hall Effect, for the embodiment in which the motor operates with the permanent magnet rotor.

(58) In FIG. 11 the location of the sensor element 116 of Hall Effect, which is situated in an angular position at a variable gap range from 0? up to 45? of advancement relative to the magnetic pole is shown in detail. In a preferred embodiment, said sensor element 116 is advanced about 17? relative to the magnetic pole, which enables choosing an optimal advanced shot angle as a function of motor best efficiency.

(59) Sensor element 116 is employed for measuring intensity of magnetic fields giving the possibility of performing an adjustment to the turning off and on of the coils by a gap in the control signal time, thus increasing efficiency and motor power.

(60) The sensor position in the art is at 0?, namely, in the neutral point between the two poles, which only enables delaying the turning on of the coils; while the invention of the present invention (new art), allows delaying or advancing the turning on of the coils by programming a microprocessor, which is installed in a control card. The microprocessor allows the introduction of a control program to maintain motor efficiency.

(61) Regarding FIGS. 12, 13A and 13B, they show details of lamination of the rotor element 103 of the present invention, which is characterized by having two embodiments.

(62) The first embodiment is shown in FIG. 12, which corresponds to a squirrel-cage type rotor element 103, which, as mentioned above, consists of a plurality of conductive bars 117, a pair of short-circuited rings 118 placed with the plurality of conductive bars 117, a support body 119 and an arrow element 120 crossing the support body 119 by its center, both elements being firmly joined to one another. The rotor element 103 rotates due to the principle of induction of electric currents induced by the magnetic field of the stator element 102, with a torque being thus generated. Both the conductive bars 117 and the couple of rings 118 are manufactured with metal material preferably employing pressure injected aluminum (die casting), while the arrow element 120 is preferably manufactured with steel.

(63) The second embodiment is shown in FIGS. 13A and 13B, which correspond to a permanent magnet type rotor element 103, which consists of a permanent magnet ring 121, a support body 122 being inserted into the permanent magnet ring 121 and an arrow element 124 crossing the support body 122 by its center. The support body 122 further includes a plurality of striations 123 throughout its circumference, so as to be able to couple with the permanent magnet ring 121. In this embodiment, shade coils 125 are eliminated from the stator element 102 (see FIG. 5).

(64) According to the above, it will be possible to observe that the design of the induction motor 100, subject of the present invention, incorporates a novel stator element 102, which can operate both with squirrel cage type motors and with electronically switched permanent magnet type motors.

(65) For this permanent magnet type of motors, the motor 100 should include an electronic control card (not shown in the figures), which may or may not include feedback from a sensor element 116 of Hall Effect like the one shown in FIGS. 10 and 11, described above. Likewise, the electronically switched motor 100 can also be used without the sensor element 116, such that the position of the magnetic fields is determined by computer algorithms previously stored in the electronic control card, thus determining the optimum shot time or angle for shooting the signal which turns one of the coils off and on.

(66) It is worth mentioning that electronically switched permanent magnet motors turn out to be more efficient in their operation than shaded poles induction motors, since neither the losses generated by the shade coils 125 nor the electrical losses generated by losses in the rotor element 103 of the squirrel cage type are there.

EXAMPLES

Experiment I

(67) A shaded poles induction motor of the present invention (Motor ROBEL Q9-580-690-27-312) and one of the best motors of its type and category from the state of the art available in the market (Motor ELCO NU9-20-2) were subjected to a series of tests to measure energy consumption and angular velocity at the same work load. The obtained values were compared and the following conclusion was reached: The new induction motor compared to the previous art motor, presents an average saving of about 55% in electric energy consumption.

Experiment II

(68) An electronically switched motor of the present invention (Motor ROBEL ECMQ 16WO) and one of the best motors of its type and category from the state of the art existing in the market (Motor A.O. SMITH E128044 16WO) were subjected to a series of tests to measure energy consumption and angular velocity at the same work load. The obtained values were compared and the following conclusion was reached: The electronically switched motor (permanent magnet) of the present invention, compared against the electronically switched motors of their same capacity, presents savings of up to about 28.82% in energy consumption.

Experiments Development

(69) For both experiments the comparative test consisted in tabulating and plotting the results of the energy consumption measurement and angular velocity measurement tests to which the motors of the present invention were subjected (ROBEL Q9-580-690-27-312 and ROBEL ECMQ16WO), comparing them against the results of the energy consumption measurement and angular velocity measurement tests to which the motors of the current art were subjected (ELCO NU9-20-2 and A.O. SMITH E128044) using the same work load for both types of motors by rotating a blade or propeller of identical characteristics.

(70) In the case of induction motors (experiment I) a blade of 203.2 mm?30? coupled to the motor was utilized; and in the case of electronically switched motors (experiment II) a blade of 254 mm?30? coupled to the motor was utilized.

(71) The points assessed at a determined scale and with working voltage ranges were the following:

(72) a).Energy consumptions in WATTS; and,

(73) b).Motor angular velocity in revolutions per minute (RPM).

(74) The results obtained for induction motors (experiment I) are shown in Tables III and IV and in FIGS. 14 and 15; while for electronically switched motors (experiment II), the results are shown in Tables V and VI and in FIGS. 16 and 17.

(75) TABLE-US-00003 TABLE III MOTOR ROBEL 1/70HP MODEL Q9-580-690-27-312 LAMINATION PACKAGE WIDTH 14.73 mm (0.580 inches) BLADE OR PROPELLER OF 203.2 mm (8 inches) ? 30?, 5 SHOVELS VOLTAGE POWER REVOLUTIONS VAC CURRENT I CONSUMED W RPM 100 0.248 15.59 1513 105 0.252 16.55 1556 110 0.256 17.38 1586 115 0.261 18.30 1606 120 0.268 19.40 1626 125 0.276 20.41 1638 130 0.286 21.50 1654 135 0.296 22.95 1672

(76) TABLE-US-00004 TABLE IV MOTOR ELCO 1/70HP MODEL NU9-20-2 LAMINATION PACKAGE WIDTH 19.05 mm (0.750 inches) BLADE OR PROPELLER OF 203.2 mm (8 inches) ? 30?, 5 SHOVELS VOLTAGE CONSUMED REVOLUTIONS VAC CURRENT I POWER W RPM 100 0.345 23.30 1536 105 0.356 24.74 1552 110 0.368 26.49 1578 115 0.382 28.42 1588 120 0.393 30.00 1607 125 0.407 32.01 1620 130 0.423 34.25 1626 135 0.439 36.48 1631

(77) From the results obtained in both tables, it can be seen that motor ELCO NU9-20-2 attached to a blade of 203.2 mm (8 inches?30?) and 5 shovels, consumes more energy than motor ROBEL Q9-580-690-27-312 in all tests carried out when they are subjected to the same predetermined voltage. For instance, by applying a voltage 115 VAC, motor ELCO NU9-20-2 consumes 28.42 Watts of energy and makes the blade spin at an angular speed of 1588 revolutions per minute (RPM), while motor ROBEL Q9-580-620-27-312 attached to the same size of blade, by applying a 115 VAC voltage consumes 18.3 Watts of energy and makes it spin at an angular speed of 1606 RPM.

(78) The results shown in tables III and IV and depicted in FIGS. 14 and 15 were obtained as it was mentioned above, assessing the performance of each approved motor, using the same workload, that is, a five-shovel blade with a diameter of 203.2 mm (8 inches?30?) at the pointed out different voltages.

(79) As it can be observed, the motor of the present invention (ROBEL Q9-580-620-27-312) consumes less current, less energy and produces a greater angular speed than the state of the art motor (ELCO NU9-20-2). Both motors being designed to do the same job give a power of 9 W; however, they present differences in their consumptions, therefore it can be determined from the obtained results that the new motor is more efficient in its performance.

(80) From tables III and IV, it can also be observed that the lamination package width of motor ELCO NU9-20-2 is of 19.05 mm (0.750 inches), while for the motor of the present invention, the lamination package width is 14.73 mm (0.580 inches), which enables obtaining a cost cut in the lamination package width of 4.31 mm (0.170 inches). In view of the above mentioned, it can also be concluded that the prior art stators use 29% more of the material in their lamination.

(81) On the other hand, using a five-shovel blade with a 30? angle for both cases, the motor of the present invention (ROBEL Q9-580-690-27-312) with an output capacity of /70 HP (9 Watts) presents a voltage of 115 VAC and a consumption of about 18.3 Watts, giving 1606 RPM, while the state of the art motor (ELCO NU9-20-2) with an output capacity 1/70 HP (9 Watts) presents a voltage of 115 VAC and a rough consumption of 28.42 Watts, giving 1588 RPM, which results in 55.30% more of the electric energy consumption and 1.13% less RPM compared with the motor of the present invention.

(82) With the obtained results in the completed tests and shown in tables I and II, as well as what can be noted in FIGS. 14 and 15, it can be concluded that motor ELCO NU9-20-2 consumes about 55% more energy than motor ROBEL Q9-580-620-27-312 and gives a slightly minor power.

(83) TABLE-US-00005 TABLE V MOTOR ROBEL ECMQ16WO LAMINATION PACKAGE WIDTH 19.05 mm (0.750 inches) BLADE OR PROPELLER OF 254 mm (10 inches) ? 30?, 5 SHOVELS VOLTAGE POWER REVOLUTIONS VAC CURRENT I CONSUMED W RPM 100 0.681 21.9 1559 105 0.675 21 1558 110 0.676 21.8 1556 115 0.679 21.7 1557 120 0.657 22.1 1555 125 0.658 22 1557 130 0.672 22.2 1558 135 0.662 22.2 1556

(84) TABLE-US-00006 TABLE VI MOTOR A.O. SMITH E128044 16WO LAMINATION PACKAGE WIDTH 19.05 mm (0.750 inches) BLADE OR PROPELLER OF 254 mm (10 inches) ? 30?, 5 SHOVELS VOLTAGE CONSUMED REVOLUTIONS VAC CURRENT I POWER W RPM 100 0.6 22 1545 105 0.597 22.4 1556 110 0.595 24.9 1555 115 0.584 26.5 1557 120 0.589 26.9 1555 125 0.581 27.1 1555 130 0.587 28.1 1558 135 0.584 28.6 1556

(85) From the results obtained in both tables, it can be seen that motor A.O. SMITH E128044 16WO attached to a blade of 25.4 cm (10)?30? and 5 petals, consume more energy than motor ROBEL Q9-580-690-27-312 in almost all tests carried out when they are subjected to a same predetermined voltage. For instance by applying a 115 VAC voltage, motor A.O. SMITH E128044 16WO consumes 26.50 watts of energy and makes the blade spin at an angular speed of 1557 revolutions per minute (RPM), while motor ROBEL ECMQ 16WO attached to the same size of blade, by applying a 115 VAC voltage, consumes 21.7 watts of energy and makes it spin at an angular speed of 1557 RPM.

(86) The results shown in tables V and VI and depicted in FIGS. 16 and 17 were obtained as above mentioned, assessing the performance of each approved motor, using the same workload, that is, a five-shovel blade with a diameter of 254 mm (10 inches?30?) at the pointed out different voltages.

(87) As it can be noted, the motor of the present invention (ROBEL ECMQ 16WO) consumes less energy, a little more current and it produces an angular speed practically equal to the state of the art motor (A.O. SMITH E128044 16WO).

(88) From tables V and VI it can also be observed that the lamination package width both, of motor A.O. SMITH E128044 16WO, as well as of motor ROBEL ECMQ 16WO is of 19.05 mm (0.750 inches).

(89) On the other hand, using a five-shovel blade with a 30? angle for both cases, the motor of the present invention (ROBEL ECMQ 16WO) presents a voltage of 115 VAC, a consumption of about 21.7 Watts, giving 1557 RPM, while the state of the art motor (A.O. SMITH E128044 16WO) presents a voltage of 115 VAC, a rough consumption of 26.45 Watts, giving 1557 RPM, which gives the result of additional 21.88% of electric energy consumption, compared with the motor of the present invention.

(90) With the obtained results in the completed tests and shown in tables V and VI, as well as what it is observed in FIGS. 16 and 17, it can be determined that motor A.O. SMITH ELCO NU9-20-2 consumes up to about 28.82% more energy than motor ROBEL ECMQ 16WO and gives practically the same power.

(91) As it can be noted, tables III, IV, V, and VI show values obtained by subjecting the induction and electronically switched motors of the present invention, as well as the aforementioned state of the art motors, to the corresponding tests, results of which allow to objectively show and give a clear idea of the energy consumption conservation achieved with induction and electronically switched motors of the present invention.

(92) In addition, it is also important to mention that the electric motor of the present invention in its squirrel-cage type rotor embodiment, presents an efficiency between 38% and 50%, while in the permanent magnet embodiment its efficiency exceeds 70%. The conventional state of the art induction motors only have an efficiency between 18% and 28%, while conventional electronically switched motors present an efficiency from 55% to 65%.

(93) On the other hand, relative to punched electric grade sheets, as it was already mentioned, depending on the motor power, the number of sheets is reduced or increased (lamination package) in the stator and the rotor. It is important to mention that the lamination package width can modify the motor efficiency.

(94) Additionally, the thinner the sheet width is, the better characteristics the motor will have, presenting minor losses generated by parasite currents or Eddy currents. The customary minimum width is 0.50 mm.

(95) The shaded-pole induction motor convertible into a permanent magnet motor, which is the object of the present invention, allows for a better energetic efficiency due to its new design, since the electric resistance of the stator and rotor winding is reduced, whereby electric losses are also reduced by the Joule effect.

(96) Another very important characteristic of both versions of motors is that the size of the motor does not vary with a new design of the induction motor, keeping its standard size for this type of motors.

(97) The main application of this kind of motors is found in refrigerators of commercial type for convenience stores, ice-cream parlors, restaurants, or retail stores, etc.; or in the industry that provides vent, heating, and air conditioning systems (HVAC), which are totally compatible with the characteristics and arrangement of the state of the art electric motors, which allows for modifications and substitutions without making any changes to the equipment or system where it is to be placed.

(98) Even when in the prior description the preferred embodiments of the present invention have been described and shown, emphasis should be made on the fact that numerous modifications can be made thereto, such as using the design of the motor of the present invention for motors of different sizes, capacities and power, without departing from the actual scope of the invention; therefore, the present invention should not be restricted, except for what the prior art and the attached claims require.