RU2014711C1 - Three-phase winding with pole change-over - Google Patents

Abstract

FIELD: asynchronous motors. SUBSTANCE: winding of stator of asynchronous motor is composed of 24 coil groups with leads from their starts and finishes. Switching gears (7 three-pole and 1 two-pole) so connect coil groups that they form over bore of motor stator phase zones with integral number of coils per zone. When three-phase voltage is fed to input leads of winding the latter forms magnetic field in air gap which first spatial harmonic rotates in one direction with angular velocity dependent on number of pairs of poles. Depending on position of switches angular velocity is equal to 375 rpm with connection for 8 pairs of poles, 750 rpm with connection for 4 pairs of poles, 1500 rpm with connection for 2 pairs of poles and 3000 rpm with connection for pair of poles. EFFECT: expanded operational capabilities of motors. 3 dwg, 2 tbl

Description

 The invention relates to electric machines and can be used in electrical engineering to create three-phase four-speed short-circuited asynchronous motors with 1/2/4 and 8 pairs of poles and one stator winding / designed to drive mechanisms with constant power - wheel pairs / main movement mechanisms of metal cutting machines and etc.

 Known three-phase pole-switchable four-speed winding for 1/2/3 and 4 pairs of poles / single layer / consisting of 18 identical coils evenly distributed over the bore of the motor stator with a pitch of 5 gear divisions; coils are divided into 12 parts / of which 6 contain one coil and 6 contain two coils. The winding is connected according to the scheme D / D / D / D / has phase zones with a width of 60/60/120/120 el. city / equipped with 24 leads / 2 conclusions from each part. The winding is controlled using a drum switch with 57 pairs of contacts [1].

The winding has a number of drawbacks: a complex circuit of switching the number of pole pairs / the presence of lower spatial harmonics of the MDS at p = 1 and p = 4 / which impairs the starting properties of the motor / insufficiently high power use of a four-speed asynchronous motor with such a winding compared to a single-speed 4-pair motor poles (P $\genfrac{}{}{0ex}{}{\text{*}}{\text{2}}$ = 0.78).

Known three-phase pole-switchable winding for 1/2/3 and 4 pairs of poles / two-layer / consisting of 36 identical uniformly distributed coils with a pitch of 5 gear divisions; coils are divided into 12 parts / of which 6 parts contain two coils and 6 - four coils. The winding is connected according to the scheme D ² / D ² / D ³ / D ² / has phase zones with a width of 60/120/120/120 el. hail. and equipped with 24 pins on the control circuit. The winding is controlled using a drum switch with 57 pairs of contacts [2].

The winding [2] has the same drawbacks / as the winding [1] and differs from the latter in slightly better filtering properties / but somewhat worse in the use of motor power (P $\genfrac{}{}{0ex}{}{\text{*}}{\text{2}}$ = 0.72).

 Known four-speed pole-switched winding for 1/2/3 and 4 pairs of poles / two-layer / consisting of 12 coil groups / forming 3 identical parts in the form of a T-shaped connection of horizontal and vertical branches [3].

The horizontal and vertical branches consist of two successively opposed included coil groups with the same total number of turns (W ₁ ). Each of the three parts is equipped with 6 conclusions on the control circuit; from the beginning / middle and end of the horizontal branch / having a total number of turns 2W ₁ ; from the middle and end of the vertical branch / as well as the additional output / which divides the vertical branch in 3 sections with the numbers of turns W ₁ , W ₂ = 0.73 W ₁ and W ₂ = 0.17 W ₁ .

)-при p = 1. При этом во избежание возникновения уравнительных токов вертикальная ветвь имеет число витков W₂=

W₁; звезда с 4 параллельными ветвями по W₁ витков в каждой/ т.е. схема Y⁴- при p = 2; Т-образная схема с 3 параллельными ветвями (T³)- при p = 3. Для обеспечения симметрии линейных ЭДС вертикальная часть Т-образной схемы выполняется с W₂=

W₁; при p = 4 - звезда с 2 параллельными ветвями с числом витков 2 W₁ в каждой ветви. При включении на p = 3 Т-образные части соединяются параллельно; при остальных числах пар полюсов горизонтальные ветви Т-образных частей соединяются в треугольник/ а вертикальные ветви вместе с горизонтальными образуют указанные схемы (

, Y⁴, Y²).The following phase connection schemes are used in the winding: combined circuit YD (

) for p = 1. Moreover, in order to avoid the occurrence of equalizing currents, the vertical branch has the number of turns W ₂ =

W ₁ ; a star with 4 parallel branches of W ₁ turns in each / i.e. scheme Y ⁴ - at p = 2; T-shaped scheme with 3 parallel branches (T ³ ) - at p = 3. To ensure the symmetry of the linear EMF, the vertical part of the T-shaped scheme is performed with W ₂ =

W ₁ ; when p = 4 - a star with 2 parallel branches with the number of turns 2 W ₁ in each branch. When turned on at p = 3, the T-shaped parts are connected in parallel; with the remaining numbers of pairs of poles, the horizontal branches of the T-shaped parts are connected into a triangle / and the vertical branches together with the horizontal ones form the indicated patterns (

, Y ⁴ , Y ² ).

 The use of unconventional phase connection schemes at p = 1 and p = 3 provides a simplification of the control circuits for the number of pole pairs / but worsens the electromagnetic characteristics of the motor.

Permissible value of the converted power of a four-speed motor with such a winding (P $\genfrac{}{}{0ex}{}{\text{*}}{\text{2}}$ _min ) is only 72/5% of the power of a single-speed motor with 4 pairs of poles.

A four-speed pole switchable winding is known for 1/2/4 and 5 pairs of poles / two-layer / consisting of 12 equally uniformly distributed coil groups / forming 3 identical parts in the form of a T-shaped connection of horizontal and vertical branches. Horizontal and vertical branches contain two successively counter-connected coil groups with the same number of turns (W ₁ ).

при p₁=1 и p₄=5; звезда с 4 или 2 параллельными ветвями - при p₂= 2 и p₃= 4 соответственно.The following phase connection schemes are used in the winding: combined YD circuit

when p ₁ = 1 and p ₄ = 5; a star with 4 or 2 parallel branches - with p ₂ = 2 and p ₃ = 4, respectively.

 The winding has 12 pins per control circuit; switching the number of pairs of poles is carried out using switches and switches with 32 pairs of contacts.

The winding [4] has even lower electromagnetic properties / than the winding [3]: the minimum value of the motor power with such a winding is only 36% of the power of a single-speed motor with p ₄ = 5 / which makes the use of such a winding impractical.

Known three-phase three-speed pole-switchable winding for 1/2 and 4 pairs of poles / two-layer / three-zone / made of 12 coil groups with the same coil / with pitch Y = τ ₃ / divided into 12 parts with taps from their beginnings and ends. The winding is connected according to the star circuit with one parallel branch at all turns (Y / Y / Y) and is controlled by 4 switches / having 22 pairs of contacts. The winding provides high power utilization of the induction motor (P $\genfrac{}{}{0ex}{}{\text{*}}{\text{2}}$ _min = 0.844) in constant power drives [5].

The disadvantage of the winding [5] / as well as the indicated four-speed windings [1-4] / is the limited scope due to the relatively narrow range of regulation of angular velocity Ω _max / Ω _min / equal to 4 for windings [1, 2, 3 and 5] and 5 for winding [4].

 By technical solution, the winding [5] is closest to the claimed proposal and adopted as a prototype.

 The aim of the invention is to expand the scope of the pole-switched three-phase three-zone windings by increasing the range of regulation of the angular velocity of the motor while maintaining its high electromagnetic properties.

 To achieve this goal, a three-phase pole switchable winding is proposed for four numbers of pole pairs / two-layer / three-zone / star-connected with one parallel branch in each phase for all numbers of pole pairs / consisting of identical uniformly distributed coils / entering into coil groups of S adjacent to each other lying in series according to the included coils (S = 1, 2, 3 ...) / the winding is made up of 1/2/4 and 8 pairs of poles / consists of 24 coil groups / divided into 24 identical parts with numbers A1-A8 / B1-B8 / C1-C8 so / that reel gr packs with numbers 1/10/4/19/7/16/22/13 are included in parts A1 / A2 / A3 / A4 / A5 / A6 / A7 / A8, respectively / reel groups with numbers 17/2/20/11 / 23/8/14/5 are included in parts B1 / B2 / B3 / B4 / B5 / B6 / B7 / B8 respectively / reel groups with numbers 9/18/12/3/15/24/6/21 are included in parts C1 / C2 / C3 / C4 / C5 / C6 / C7 / C8, respectively / the parts of the winding are connected to 8 switches / of which the first switch is bipolar / has two groups of terminals (first and second) with 3 terminals in each group - upper / middle and lower / with the ability to close the circuit between the middle and upper or between the middle and neither the outputs / second / third / fourth / fifth / sixth / seventh and eighth three-pole switches / have 3 groups of terminals (first / second and third) with 3 outputs in each group - upper / middle and lower with the possibility of circuit closure between the middle and the upper or between the middle and lower terminals / and the beginning of the part A1 is connected to the external terminal A / the beginning of the parts B1 and C1 are connected to the first and second upper terminals of the first switch / the ends of the parts A1 / B1 / C1 are connected to the first / second and third upper respectively conclusions and the fifth switch / the beginning of the parts A2 / A3 / A4 / A5 / A6 / A7 / A8 are connected to the first middle terminals of the switches P5 / P2 / P6 / P3 / P7 / P4 / P8, respectively / the ends of the parts A2 / A3 / A4 / A5 / A6 / A7 are connected to the first upper terminals of the switches P2 / P6 / P3 / P7 / P4 / P8, respectively; the beginning of the parts B2 / V3 / V4 / V5 / V6 / V7 / V8 are connected to the second middle terminals of the switches P5 / P2 / P6 / P3 / P7 / P4 / P8, respectively / the ends of the parts B2 / V3 / V4 / V5 / V6 / V7 are connected with the second upper terminals of the switches P2 / P6 / P3 / P7 / P4 / P8, respectively; the beginning of the parts C2 / C3 / C4 / C5 / C6 / C7 / C8 are connected to the third middle terminals of the switches P5 / P2 / P6 / P3 / P7 / P4 / A8, respectively / the ends of the parts C2 / C3 / C4 / C5 / C6 / C7 are connected with the third upper terminals of the switches P2 / P6 / P3 / P7 / P4 / P8, respectively; the ends of the parts A8 / B8 / C8 are connected together; the switches are equipped with jumpers / connecting the first and second middle terminals of the first switch with external terminals B and C, respectively / the first upper terminal of the first switch with the second lower and the first lower with the second upper terminals of the same switch; the first upper terminals of the switches P3 / P4 / P5 / P7 with the second lower / second upper with the third lower and third upper with the first lower terminals of the same switches; first lower terminals of switches P2 / P6 / P8 with second upper / second lower with third upper / third lower with first upper terminals of the same switches.

 The proposed goal is achieved by increasing the number of coil groups and the number of parts / redistribution of coil groups in parts and changing the connection scheme of the parts.

 In FIG. 1 shows a circuit diagram of the proposed winding; figure 2 is a vector diagram of a coil EMF winding at S = 1 and Z = K = 24; figure 3 - scan pattern of the proposed winding at S = 1, Z = 24.

 In FIG. 1 through A1-A8 / B1-B8 / C1-C8 24 parts of the winding are indicated / and the numbers of the coil groups / included in the corresponding parts are indicated in brackets; through П1 the two-pole switch is designated and through П2-П8 - three-pole switches / used to control the number of pole pairs. The arrows at the bottom of the switches indicate the direction of movement of their movable contacts when the winding is turned on by the number of pole pairs indicated next to the arrow. With the initial position of the switches indicated in FIG. 1, the circuit is prepared to turn on the winding for 8 pairs of poles / and the inclusion is made by applying a three-phase voltage to the input terminals of the winding / indicated by the letters A / B / C.

 The numbers 1-24 in figure 2 denote the numbers of the coils / to which the corresponding EMF vectors for the winding with S = 1 and Z = K = 24 belong. Since at S = 1, the numbers of the coils coincide with the numbers of the coil groups / figures 1-24 in FIG. 2 simultaneously indicate the numbers of the reel groups. One / two and three strokes indicate the emf vectors of the coils / which are connected in series according to the phases A / B and C of the winding, respectively. In figure 3, the numbers 1-24 indicate the numbers of the coils / and the letters H and K indicate the conclusions from the beginnings and ends of the corresponding parts.

 From FIG. 2 shows / that the proposed winding for all numbers of pole pairs is symmetrical / has an integer number of coils per phase zone with a width of 120 el. hail. Also, the windings / as is known / do not create the lowest spatial harmonics of the MDS / but for Y ≠ τ / which takes place in this case / create the higher even harmonics of the MDS.

 Obtained on the basis of figure 1, the distribution of parts and (coil groups) in phases is given in table 1.

 It is easy to verify that / that the circuit diagram shown in Fig. 1, when the switches are installed in the appropriate positions, implements the phase distribution of the coil groups and parts / shown in Fig. 2 and in Table 1.

 The proposed winding works as follows.

= πD_a/8/ первая пространственная гармоника которого вращается с угловой скоростью
n₄= 60f₁/P₄= 3000/8 = 375 об/мин/ где f₁- частота сети/ равная 50 Гц.When applying a three-phase voltage to the input terminals of the A / B / C winding and the initial position of the switches shown in Fig. 1, the coil groups are distributed according to the phases according to figure 2 / g / while the winding creates a magnetic field in the air gap of the machine with a period of 2τ ₄ = πD _a ·

= πD _a / 8 / whose first spatial harmonic rotates with angular velocity
n ₄ = 60f ₁ / P ₄ = 3000/8 = 375 rpm / where f ₁ is the mains frequency / equal to 50 Hz.

/ вращающегося в том же направлении с угловой скоростью n₃= 60f₁/P₃= 3000/4 = 750 об/мин.When the switches P1 / P5 / P6 / P7 / P8 are switched to the lower position in Fig. 1, the coil groups are distributed in phases according to Fig. 2 / c /, as a result of which a magnetic field arises in the air gap of the machine with a period of 2τ ₃ = πD _a · 6 / 24 =

/ rotating in the same direction with an angular speed of n ₃ = 60f ₁ / P ₃ = 3000/4 = 750 rpm.

When the switch P1 is set to the upper position in Fig. 1 / switches P2 / P4 and P5-P8 to the lower position / coil groups will be distributed in phases according to Fig.2 / c and in the air gap there is a magnetic field with a period of 2τ ₂ = πD _a / 2, rotating at a speed of n ₂ = 60f ₁ / ₂ =1500 rpm. When you install all the switches P1-P8 in the lower _{one of} figure 1 position coil groups are distributed according to phases according to figure 2 / a and in the air gap of the engine there is a main magnetic field with a period of 2τ ₁ == πD _a / rotating with speed
n ₁ = 60f ₁ / P ₁ = 3000/1 = 3000 rpm

Thus / the proposed winding provides a stepwise adjustment of the angular velocity of the magnetic field in relation
n ₁ : n ₂ : n ₃ : n ₄ = 8: 4: 2: 1.

Comparison of pole-switching windings is carried out according to the energy indicators of induction motors with compared windings. The calculation is made according to the following formulas:
M $\genfrac{}{}{0ex}{}{\text{*}}{\text{i}}$ = M _i / M _b = B $\genfrac{}{}{0ex}{}{\text{*}}{\text{δ}}$ _max K _obi ;
P $\genfrac{}{}{0ex}{}{\text{*}}{\text{P}}$ _pi = P _pri / P _b = M $\genfrac{}{}{0ex}{}{\text{*}}{\text{i}}$ P _max / P _i / where the basic values of the moment and the converted power P _pr are the values of the moment and power of a single-speed motor with the greatest number of pole pairs at B _δmax = B _{δdop with the} current value of the current density in the winding wires J = J _add and K _rev = 1 . The calculation results are given in table. 2. From Table 2 it is seen / that despite the expansion of the range of regulation of the angular velocity by a factor of two compared with the known four-speed windings [1, 2] and a three-speed winding [5] / the proposed winding is not only inferior / but exceeds these windings in power use in constant power drives. Converted motor power with the proposed winding is P $\genfrac{}{}{0ex}{}{\text{*}}{\text{P}}$ _p = 0.886, which is 2/6% more / than the winding of the prototype and 10/8% more / than the analogue [1].

Claims (1)

 THREE-PHASE SEMI-SWITCHING WINDING two-layer, three-zone, connected to a star with one parallel branch in each phase for all numbers of pole pairs, consisting of the same uniformly distributed coils included in the coil groups in S (where S = 1, 2, 3 ...) next lying in series according to the included coils, characterized in that the winding is made up of 1, 2, 4 and 8 pairs of poles, consists of 24 coil groups divided into 24 identical parts with numbers A1 - A8, B1 - B8, C1 - C8 so that reel groups with numbers 1, 10, 4, 19, 7, 16, 22, 13 are included in parts A1, A2, A3, A4, A5, A6, A7, A8, coil groups with numbers 17, 2, 20, 11, 23, 8, 14, 5 are included in parts B1, B2, B3, B4, B5, B6 , B7, B8, coil groups with numbers 9, 18, 12, 3, 15, 24, 6, 21 are included in parts C1, C2, C3, C4, C5, C6, C7, C8, respectively, the parts of the winding are connected to eight switches , of which the first switch is bipolar, has two groups of pins (first and second) with three pins in each group (upper, middle and lower), with the ability to close the circuit between the middle and upper or between the middle and lower pins, the second and eighth triple-pole switches , them they have three groups of terminals (first, second and third) with three terminals in each group (upper, middle and lower terminals) with the possibility of closing the circuit between the middle and upper or between the middle and lower terminals, and the beginning of part A1 is connected to external terminal A , the beginning of parts B1 and C1 are connected to the first and second upper terminals of the first switch, respectively, the ends of parts A1, B1, C1 are connected to the first, second and third upper terminals of the fifth switch, respectively, of the parts A2, A3, A4, A5, A6, A7 , A8 connected to the first averages the outputs of the switches P5, P2, P6, P3, P7, P4, P8, respectively, the ends of the parts A2, A3, A4, A5, A6, A7 are connected to the first upper terminals of the switches P2, P6, P3, P7, P4, P8, respectively, of the beginning parts B2, B3, B4, B5, B6, B7, B8 are connected to the second middle terminals of the switches P5, P2, P6, P3, P7, P4, P8, respectively, the ends of the parts B2, B3, B4, B5, B6, B7 are connected to the second upper terminals of the switches P2, P6, P3, P7, P4, P8, respectively, the beginning of the parts C3, C2, C4, C5, C6, C7, C8 are connected to the third middle terminals of the switches P5, P2, P6, P3, P7, P4, P8, respectively, the ends of the cha Tei C2, C3, C4, C5, C6, C7 are connected to the third upper terminals of the switches, respectively, the ends of the parts A8, B8, C8 are connected together, the switches are equipped with jumpers connecting the first and second middle terminals of the first switch with external terminals B and C, respectively the first upper terminal of the first switch - with the second lower and the first lower - with the second upper terminals of the same switch, the first upper conclusions of the switches P3, P4, P5, P7 - with the second lower, the second upper with the third lower and the third upper - with the first lower odes same switches: the first lower terminals of switches S2, P6, P8 - a second upper, lower second and third upper, lower third with the first upper pin of the same switches.

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