DE3334133A1 - Pole reversal on three-phase motors, using capacitors - Google Patents

Abstract

Pole reversal on three-phase motors, using capacitors for pole numbers up to 5, in the ratio 1:2:3:4:5. The method is an expansion of the known Dahlander reversal (2:4) by the stages 1, 3 and 5. Three capacitors are integrated into the circuit of a normal three-phase two-layer winding, for this purpose. By means of the capacitors, balanced three-phase operation is also made possible for stages 1, 3 and 5, but only for one operating point. Advantageous applications include, for example: 2/6/10-, 2/10-, 4/6- or 6/8 pole motors, high-voltage motors or reversible-pole single-phase motors using the Steinmatz circuit. For some ratios of pole numbers, such as 4/6- or 6/8 pole motors, one capacitor of triple capacitance, for example, is adequate, or a single-layer winding can also be used, and it is furthermore possible to select a circuit in which the capacitors in stages 2 or 4 are automatically used for compensation of the reactive current.

Description

description

Title: Pole changing on three-phase motors using capacitors Genus The invention relates to a method with a pole changing on three-phase motors up to a range of 1: 2: 3: 4: 5 the phase-rotating effect of capacitors and a special winding arrangement, however no special new type of winding.

Prior art three-phase motors have the disadvantage that they, with provided with only one winding and with a constant mains frequency only one nominal speed With so-called pole-changing windings or the use of static Frequency converters try to avoid this fact. To change the pole there there are also a variety of special windings, such as the Dahlander process or the pole amplitude modulation. Several independent windings are also used Pole-changing three-phase motors are in the ratio 1: 2: 3: 4: 5, with only one winding, not known. Also the standard work: AC special windings vonsequence (Springer-Verlag Vienna, 3rd edition, 1954) shows no solution for this The transformation of the 3-phase three-phase network using transformers is known in voltage systems with a different number of phases and different voltage values.

Criticism of the fact that a pole change over the mentioned 5 pole numbers is not yet known, remain with the known method disadvantages in those cases in which only 2, 3 or 4 pole number stages are used If the windings have a more complicated structure, there are some number of slots or winding increments, Very often methods have to be rejected because of too great a switching effort or such a loss of performance must be accepted that the; orzug, with Getting by with only one winding becomes uninteresting. The use of transformers for phase number variation can practically not be used for reasons of cost.

The object of the invention is to apply to three-phase motors that have only one winding enable pole switching up to a ratio of 1: 2: 3: 4: 5 must be that the manufacture of the winding, the behavior of the motors in operation, the switching effort when changing the number of poles and the total capacity that the aforementioned pole switching also leaves the application value. In addition to switching over all 5 levels, p are in particular recommended over only 2, 3 or 4 levels.

For each output winding, the number of poles level is 2 (4-pole, 8-pole, etc.), including the Dahlander switching ratio integrated into the process from 2: 4, a total of 26 different pole number combinations.

The 2: 4 switching ratio must of course be taken out of the protection.

Solution The task is carried out with a device of the generic type solved the characterizing features of claims 1 to 4. These 4 claims differ regarding the arrangement of the coil groups, the different connections the capacitors to the winding and the connection conditions for the number of poles 2 and 4. The arrangement of the capacitors is more advantageous in claims 3 and 4 than in claims 1 and 2, as soon as a direction of rotation reversal for steps 1, 3 or 5 is required.

For the point of view of pole changing, the capacitors remain Basically without function for levels 2 and 4. Starting point of the explanation of the concept of the invention is the number of poles 2 for the drafting of the description of the invention and also in the figurative representations, this pole number level is 2 as small as possible, i.e.

4-pole, has been set. This also has to be done for the drafting of the patent claims apply insofar as they relate to figurative representations. An extension of the Number of poles level 2 to 8, 12 or 16 poles etc. is trivial and is intended for the sake of clarity because of, omitted.

To change the pole it must be achieved that the pole number to pole number Changed requirements of the individual winding parts (coil groups) on the phase position of the assigned voltages are fulfilled 12 coil groups, the beginnings of which require voltages of the following angular distance «1: Level 1: α1 = 30 ° (cosγ = cos 15 ° = 0.96) Level 2: α1 = 60 ° (cosγ arbitrary) Level 3: α1 = 90 ° (cosγ = cos 45 ° = 0.707) Level 4: i1 = 120 ° (cosγ arbitrary) Level 5: α1 = 150 ° (cosγ = cos 75 ° = 0.26) The three-phase network L1 / L2 / L3, with the phase positions 0/120/240, can meet the requirements of levels 2 and 4, with within the winding also the phase positions 60/180/3000 are generated automatically. The present invention uses one capacitor per string for the other stages, with the task of half a strand with a voltage of the required interphase position 30.90 or 1500 zu The intermediate phase angle within each phase becomes α2 called. The phase distance α2 between the partial phase positions of each strand becomes a multiple of the group distance α1. Thus, because of the periodicity, the following α2 values are possible, whereby the angles (α2 + 180 °) are left out must: Level 1: α2 = 30 °, 90 °, 150 ° Level 3: α2 = 900 Level 5: oC2 = 1500, 90 °, 300 It should be clearly stated here that the required angle <2, at constant capacitance of the capacitors, is only available exactly for one operating point, and indeed when the capacitor corresponding to the phase angle (cos γ) between the current (I) and the voltage (U) at the individual coil groups and the current level (I). This refers to the cos t that is applied to the individual coil groups As a result of the capacitor reactive currents (I)) the power factor on the network side is (cosγN) changed between mains voltage (Uetz) and mains current (INetz), i.e. improved or even capacity quoted at levels 1, 3 and 5 symmetrable performance factors have been added to the list above the different interphase angles oC2 result in different voltages on the capacitors (Uc) and thus also on the coil groups connected in parallel.

For the switching ratios 2: 3 and 3: 4, according to claims 5 and 6, there is the possibility of the two-layer A single-layer winding that is easier and cheaper to manufacture is the reason this lies in the fact that the prescribed versions ensure that both the winding pitch as well as the total coil group condition is fulfilled As is known, the winding steps should correspond to the pole pitch.

Claim 7 explains a measure with which operating points other than those previously indicated can also be symmetrized. This method can only be used if there is no risk of equalizing currents due to the parallel connection of winding parts with different numbers of turns with capacitors connected in parallel, the number of turns 1 and the remaining "number of turns 21" should be obtained. The number of turns ratio "v" (number of turns 1 / number of turns 2) must then be set as follows: The angle /, ie the phase shift between current and voltage, is in these expressions the parameter of the operating point for which the motor, by means of capacitors, shows a behavior that is similar to that which it would have on a 4- or 12-phase three-phase network.

The measure described can result in unequal current densities in the Coil groups remain possible, but the extent of the asymmetry would be even greater if the operating point is insufficiently symmetrical, with a winding that is optimally adapted a nominal load point with lower vibration, noise and loss is obtained than without Modification present. Preferably, the winding cross-section remains for all coil groups same, for single-layer windings z. B. can deviate from this rule.

Of course, (claim 8) with a small additional Switching devices can be achieved that the capacitors also for the number of poles 2 and 4, at least as reactive current compensation, can be used.

The claims 9 and 10 explain in which special cases the Usually 3 capacitors can be replaced by only one of 3 times the capacity.

In the embodiment according to claims 11 and 12, i.e.

for the switchover in the ratio 2: 3 or 3: 4, the capacitors are in the permanently connected state, capable of reactive current compensation for the number of poles 2 and 4 to effect.

In principle, as patent claim 13 expresses it, with everyone Pole number stage, which requires a three-phase connection, to the well-known Steinmetz circuit This means that an additional capacitor is required, on the other hand but the possibility offered a whole range of them with the procedure described here of pole-changing ratios also for single-phase motors a multiple switching (claim 14) it can easily happen that not all provided number of poles the operating point, with only one capacitor, sufficiently balanced will.

In these cases, additional capacitors can be added to the arrangements described If required, these can also be switched after certain riotor currents can be switched on or off.

Advantages The main advantage of the invention is that the method Ren with a conventional three-phase two-layer winding, e.g. T.

even in a single-layer version, this allows the winding can be manufactured quickly and inexpensively and checked for proper manufacture High-voltage motors, in form coil design, where separate windings are extremely reluctant are carried out, all the pole-changing ratios can be used with the invention of interest for low-voltage motors, especially for high-voltage motors due to the reciprocal dependence of the capacitor capacity on the square of the Tension, advantageous designs awaited. The invention makes possible with an economical reasonable expenditure on additional components (here capacitors) and additional ones Pole switching effort (cables and contactors), a large number of pole number combinations, whereby the switchover over all 5 levels is not done by any other known method A significant advantage can also be seen in the fact that with the number of poles level 2 basically no loss of performance compared to an optimally designed one The screw-in speed version is acceptable. This fact is also not applicable to any given another solution, with the exception of solutions with transformers. It can be found here It should also be noted that in cases where the capacitors are active are, a basically desirable reactive current compensation takes place, which often Smaller connection cross-sections can be selected and a central reactive current compensation system can be dimensioned smaller. The use of capacitors is also associated with the advantage that, in addition to the phase-rotating effect, it also has an amplitude-controlling effect Have an effect, e.g. B. with the variation of the interphase angle «2. This can even with the relatively high speed spread of 1: 5 an acceptable magnetic speed Use of the dynamo sheet can be achieved, the disadvantage of the method The fact that in the number of poles 1,3 and 5 only for certain operating points a completely symmetrical three-phase operation is present. This disadvantage is however due to a targeted adaptation of the motors to the different machines so far that for many applications the benefit is reduced by the gain in performance or In addition, drivable speed levels predominate. The embodiments given in the appendix cannot be complete, the complex of possibilities is too extensive for that.

For all applications it will be important to find a compromise between the degree of symmetry of the operating point.

the auxiliary capacity (sum of all speed powers or power the main speed), the switchgear expenditure, the capacitor capacity expenditure and the general operating behavior of the engines. Explanation of the invention based on some Figures Fig. 1 winding design with 24 stator slots and a winding pitch of The 12 coil groups (number of poles level 2 = 4-pole) are numbered and have Beginning (a) and end (e) Fig. 2 arrangement of the coil groups and capacitors ge claim 1 and FIG. 1, FIG. 3 like FIG. 2 but claim 2 relating to FIG. 4 like FIG. 2 but claim 3 relating to FIG. 5 as in FIG. 2 but relating to claim 4 Fig. 6 voltage pointer stars for the number of poles 1 to 5 with the coil group designations according to Fig. ' 1 Fig. 7 Voltage pointer stars for strand U. Intermediate-bevel angle 30.90 and 1500 for number of poles level 1 Fig. 8 Vector diagrams of the voltages and currents for 2 coil groups of strand U. Intermediate phase angle 30.9 () and 150 0 for number of poles 1 according to Fig. 7 Fig. 9 Examples of the capacitor connection, in a different representation, to determine the capacitor voltage. List not complete Fig. 10 Winding arrangement according to claim 5 with 24 stator slots Fig.11 winding arrangement according to claim 6 with 24 stator slots Fig.12 voltage pointer stars for one 4/6-pole winding according to claim 7 with v = 1.7.

Fig. 13 Vector diagram of the voltages and currents for 2 coil groups of line U with 6-pole symmetrical operation. Winding according to Fig. 1i Tab. 1 Approximate Information on capacitor capacity and capacitor voltage around the operating points at 50 Hz mains frequency to be balanced Design and wiring examples Fig. 14 Most important overall scope of the external connection options according to claim 1 and Fig. 2. Due to the number of poles required in the individual case and the desired Motor behavior, the circuits to be used must be selected.

Fig.15 Corresponding to Fig.14, but internal interconnection according to patent claim 2 and 3.

Fig.16 Corresponding to Fig.14, but internal interconnection according to patent claim 3 and Fig. 4. In Fig. 16.5 a reactive current compensation for pole number stage 2 is shown, according to claim 8, the magnetic conditions correspond to the table 2, but without number of poles level 4.

Fig.17 Corresponding to Fig.14, each internal circuitry according to patent claim 4 and Fig. 5. In Fig. 17.8, reactive current compensation for number of poles stage 4 is indicated, according to claim 8.

Fig. 18 Interconnection of the capacitors for the switching ratios 1: 2: 5 and 1: 4: 5 with capacitors in delta connection according to Fig.9.3 and the claims 3 or 4.

Fig. 19 Interconnection of one capacitor with the switching ratios 2: 3 or 3: 4 according to claims 9 and 10, respectively.

Fig. 20 Interconnection for the switching ratios 2: 3 and 5: 4 according to J) atentcinsprüchen 11 or 12 for reactive current compensation in stages 2 or 4 without additional switching equipment Fig. 21 Example of a single-phase connection of a number of poles stage 1 according to claim 13 Tab. 2 The percentage relative machine flux f and the percentage relative air gap induction Bt for the circuits according to Fig. 14. Assumed winding design: number of slots 36, winding step 5/9 (# = triangle -, # = star. III = parallel connection) Table 3 As table 2 but based on FIG. 15 and a winding step of 4/9 Table 4 As Table 2 but based on FIG. 17 and on number of poles level 4 (100%) Table 5 Overview of advantageous applications of the invention. Selected and compiled from FIGS , 15,18,19 and Tables 1 to 4 capacitor capacitance and capacitor voltage (flashover values) , 00 -2 = 900 ~ -1500 Boarding, Mains voltage; mg CI U (V CCuF) US ~ ICrcF: = 138 = rmach Fi. ea =! P31 i3 270 12 ~ 9 q1'LiS 94 q 20 C3jekTR. ) 27 10 40 160 7 40 97 bi, 9.9 h60 p 3 340 4 470 1 1280 q.? till 9, t, C-per km "q 200 13 270 2 7LO q.7 to qq 4000 p 23 3130 33 200 6? Ioo i 9.1 bas 9.5 ~ 2500 18 6800 (,, c-each 1ookW 68 1800 100 2500 18 6800 9.7 to 9.9 Table 1 Fi Pol- 3'j instep zone- chord. ° (2 cosß scarf 1Z 'number (%) (%) per factor factor / line 8acaBla3 p P8 ILZsiw 2 2 1 14 29 4cj f ° 0; 254 hoo 0 ? 7.2 ~ 2 ~~~ 1T5 39 0.99 o, Z- 900 0.214 ~ 17,; 3 ~ 2 ~ 435 108 4 / A 6 65 49 61 O 92 9 F; 2 + && a 4 8 8 100 100 100 76 0 8 o 8 al w7rfr 10 4 'a0 62 45 0 0 17.10 1t) 8 ~ 85 61 0 0 * 79 0 98 1. 10 10 107134 1 4 ai O s79 0 98 1 150 ° E a26.

Table 4 Fig. Pole f Bt instep zone chord. <2 cos 14a 'number% per zue factor f - factor NS 14.1 2 80 40 45 96 <42 30 ° o, 96 Z 14.2 2 1 (: 79 54 61% o, 99 o, 42 90 o, 71 d 14 v; 2 173 86 97 o 99 42 1 0o o, 26 rQW 14.4 4 100 100 100% 0.97 o 76 1 0 all 75 /.? 6 - 51 77 61 96 e, 92 0 96 900 O 7 III 14.8 8 4 86 ~ 50 96 o, 87 0 8 all YY 14.11 10 1 128 4% 0 o o82 0o 0 6 14.10 10 40 100 722 0 o * 79 82 0 0 1 14.9 10 110 2 0 2 o. 79 o. 82 1S0 ° o. 26 Y Table 2 Fig. Fol- § B [, instep zone chord. ° (2 cost i7al- number number (%) (%) r per factor factor ePI 1 5Æw 1 2 166o 85% 099 99 O s 54 i 1542 2 129% 65% 702% O o 99 O 34 9o ° O s 1 Y 15.3 2 3669 L 186 I. "" S 19Lc96 C) LPe 0.4 1500 0.26 Y .5 /.? 6 95% 142 122q6 0 2 0 8 QS o all II 15.8 8 145 ° S 290e6 200% = o, 98 o ° all mr 15.11 10 42% 105% 58% o, 79 o, 98 4 o, 96 para 15 e 10 10 56v6 140% 7oX <o @ 98 9o O, 71 y 1 S 9 10 1 LiCj§Ó vi8ft44 1 1 Q474 °. 79 o, 98 1 50 ° °% 26 Y Table 3 Number of poles used according to number of terminals Level 2 = level 2 = patent = number of 3 pol. characters 4 pole 8 pole respond. Sagittarius 2/4/6/8/10 4/8/12/16/20 1 21 14 14.2 / .4 / .6 / .8 / .10 2/4/8/10 4/8/16/20 1 15 9 14.2 / .4 / .6 / .8 2/4/10 4/8/20 2 6 4 15.2 / .4 / .10 2/6/10 4/12/20 2 4 4 15.1x) /. 5 / .9 2/8/10 4/16/20 1 6 4 14.2x) /. 8 / .10 4/6/8 8/12/16 1 11 5 14.4 / .6 / .8 4/8/10 8/16/20 1 12 6 14.4 / .8 / .10 2/4 4/8 2 6 3 15.2 / .4 2/6 4/12 1 4 3 14.1x) /. 5 2/8 4/16 1 6 3 14.2x) /. 8 2/10 4/20 3 or 4 3 2 18.1 / 18.3 4/6 8/12 2 5 2 15.4 / .6 4/6 8/12 9 8 3 19.1 / .2 4/10 8/20 2 6 3 15.4 / .10 6/8 12/16 1 5 2 14.6 / .8 6/8 12/16 10 8 3 19.1 / .2 6/10 12/20 1 4 3 14.7 / .11x) 8/10 16/20 1 6 3 14.8 / .10 Table 5 x) # instead of # switchg.

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Claims (14)

Designation: Pole changing on three-phase motors using Capacitors Claims 1. Pole switching on three-phase motors using of capacitors, characterized in that with a symmetrically wound, three-phase, six-zone three-phase two-layer winding of pole number level 2, with an integer total number of coil groups divisible by 12 in the arrangement (1), (2), (3), (4) and (5), half of the coil grabs from (2) to (4) one capacitor per strand in parallel is switched so that a pole change for a maximum of 5 pole numbers in a ratio of 1: 2: 3: 4: 5 becomes possible, whereby level 1 with three-phase power supply via (1) and (5), level 2 with three-phase power supply via (2) and (4) with star points in (1), (3) and (5), stage 3 with single-phase power supply via (1) and (5), level 4 with three-phase power supply via (3) and star points in (1) and (5) and level 5 with three-phase power supply, if interchanged two mains supply lines, from level 1 and for levels 1 and 5 the coil groups from (2) to (4) can be arranged so that there are tensions on them that are either 30.90 or 150 degrees out of phase with those of the rest of the strand, and that with the interconnection of all groups and the dimensioning of the capacitors cen requirements of the number of poles-dependent voltage pointer stars are met as far as possible will. 2. Three-phase motor according to claim 1, characterized in that the coil groups in the range from (2) to (4) are replaced by the arrangement (6) to (8) and stage'2 with three-phase supply via (7) and star points in (1) and (5) and stage 4 with three-phase supply over (6) and (8) and star points in (1), (7) and. (cm), and for the steps 1 and 5 the coil groups in the range from (6) to (8) can be arranged in such a way that that there are tensions on them that correspond to those of the rest of the strand either 30, 90 ° or 150 ° out of phase. 3. Three-phase motor according to claim 1, characterized in that the Coil groups in the arrangement (1), (9), (10), (11) and (12), in (10) a capacitor each strand is connected, the second ends of which either form a star or a Delta connection or parallel by connecting to (1) or (12) to the groups from (1) to (10) or from (10) to (12), so that one Pole switching is possible for a maximum of 4 numbers of poles in a ratio of 1: 2: 3: 5, whereby Level 1 with three-phase power supply via (1) and (12), level 2 with three-phase power supply via (9) and (11) and star points in (1), (10) and (12) stage 3 with single-phase power supply via (1) and (12) and level 5 with three-phase power supply, when two mains supply lines are interchanged Stage 1 is created, and for stages 1 and 5 the coil groups from (1) to (10) or from (10) to (12) can be arranged so that there are tensions on them are either 30.90 or 1500 out of phase with those of the rest of the strand. 4. Three-phase motor according to claim 1, characterized in that the Coil groups in the arrangement (1), (9), (13), (14) and (15) in (13) a capacitor each strand is connected, the second ends of which either form a star or a Delta connection or by connecting to (1) resp. (15) parallel to groups from (1) to (13) or (1'3) to (15) are placed, so that a pole change for a maximum of 4 pole numbers in a ratio of 1: 3: 4: 5 is possible, with level 1 with three-phase power supply via (1) and (15), level 3 with single-phase power supply via (1) and (15), level 4 with three-phase power supply via (9) and (14) and star points in (1), (13) and (15) and Stage 5 with three-phase power supply, when two mains supply lines are swapped, from stage 1 arises, and for stages 1 and 5 the coil groups from (1) to (13) and from (13) to (15) can be arranged in such a way that there are tensions on them that lead to those of the rest of the strand are either 30.90 or 1500 out of phase. 5. Three-phase motor according to claims 1 to 3, characterized in that that a symmetrically wound, three-strand, Six-zone single-layer winding in a so-called three-tier design is used. 6. Three-phase motor according to claims 1, 2 and 4, characterized in that for switching in a ratio of 3: 4 a symmetrically wound, three-strand, six-zone Single-layer winding is used in a so-called two-tier version. 7. Three-phase motor according to one of the claims. 1 to 6, characterized in that that the coil groups T: with capacitors connected in parallel have a different number of turns than the rest of the coil groups. 8. Three-phase motor according to one of claims 1 to 7, characterized in that that the capacitors for number of poles 2 and 4 are used for reactive current compensation will. 9. Three-phase motor according to claims 3 and 5, characterized in that that a total of only one capacitor is used for the number of poles ratio 2: 3, its one connection is placed at the star point formed in (10), and the other The end is optionally connected to the star points formed in (1) or (12). 10. Three-phase motor according to claims 4 and 6, characterized in that that a total of only one capacitor is used for the number of poles ratio 3: 4, its one terminal is placed on that formed in (13), and the other end optionally is connected to the star points formed in (1) or (15). 11. Three-phase motor according to claims 1 and 5, characterized in that that for the switching ratio 2: 3 the connection of the 3 capacitors in the area from (2) to (4) is carried out in such a way that one connection in each case is in (2) and the other with a strand change in (4), is made so that, at level 2, they form a delta connection. 12. Three-phase motor according to claims 2 and 6, characterized in that that for the switching ratio 3: 4 the connection of the 3 capacitors in the range of (6) to (8) are carried out in such a way that one connection in each case is in (6) and the other with a line change in in (8) is made so that, at stage 4, they form a delta connection. 13. Three-phase motor according to one of claims 1 to 12, characterized in that that in the presence of a single-phase network, the rotary atomic stages by the known Steinmetz circuit to be replaced. 14. Three-phase motors according to one of claims 1 to 13, characterized in that the capacitors that are constantly used are connected in parallel with the capacitors after activated or deactivated by suitable devices depending on the presence of certain engine parameters will.