CN1044740A - Three fast Pole-changing using phase-mixing winding connection method and variable-pole winding - Google Patents
Three fast Pole-changing using phase-mixing winding connection method and variable-pole winding Download PDFInfo
- Publication number
- CN1044740A CN1044740A CN 89105801 CN89105801A CN1044740A CN 1044740 A CN1044740 A CN 1044740A CN 89105801 CN89105801 CN 89105801 CN 89105801 A CN89105801 A CN 89105801A CN 1044740 A CN1044740 A CN 1044740A
- Authority
- CN
- China
- Prior art keywords
- utmost point
- poles
- kinds
- winding
- pole
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Landscapes
- Induction Machinery (AREA)
- Windings For Motors And Generators (AREA)
Abstract
The 3Y/4Y/3Y+Y connection of three kinds of number of poles Pole-changing using phase-mixing windings has two kinds of numbers of poles reverse pole-conversion each other in three kinds of numbers of poles, these two kinds of numbers of poles and another utmost point then belong to the commutation pole-changing.Two and half windings, one is connected into 3Y, and three neutral points of this 3Y are another utmost point lead-out wire end points, and one is connected into one tunnel series connection.Two and half windings are along connecing and when being unified into 4Y, obtaining when reversal connection is connected into 3Y+Y, obtaining the reversal connection series connection utmost point along connecing the utmost point in parallel.Half winding that is connected into 3Y says it also is the 3Y connection to another utmost point, and being its neutral point along three lead-out wire end points that connect the utmost point in parallel.Three kinds of numbers of poles need 9 of lead-out wires altogether, four of reversing switches.
Description
The invention relates to the new connection of variable-pole winding of three kinds of numbers of poles of energy conversion, it is identical that three kinds of numbers of poles of this winding are counted N by the equivalent utmost point phase groove of pole-changing conceptual design groove number, winding arrangement characteristics are identical, by being divided into to number I with to number II two and half windings to belonging to, (respectively organize coil by belonging to mutually and can being divided into 18 groups of coils with organizing the alias representative to genus, after the group by each utmost point mutually number with to number forming), can realize the multi-channel parallel Pole-changing using phase-mixing.
In the prior art, three-speed motor generally has patterns such as double-iron core double winding, single iron core double winding, single iron core simplex winding, and desirable pattern should be single iron core simplex winding.But the pole-changing equipment of existing simplex winding three-speed motor is all very complicated, for example adopts the pole-changing motor of 2Y/2Y/2Y and 2 △/2 △/2Y connection to need 9 of lead-out wires, 9 of reversing switches; Adopt the pole-changing motor of 2 △/2Y/2Y connection to need 12 of lead-out wires, 12 of reversing switches; Adopt ▲/▲/pole-changing motor of 3Y connection needs 13 of lead-out wires, 10 of reversing switches.Fairly simple connection is some the three fast variable-pole winding that relates in the Chinese invention patent " pole-changing method using phase-mixing " of application number 85100451.Introduce according to this method, six kinds of identical numbers of poles of equivalent utmost point phase groove number (by pole-changing conceptual design groove number) if winding arrangement characteristics are identical, just can be realized the multi-channel parallel Pole-changing using phase-mixing.This method with 18 groove conversion 2,4,8,10,14,16 totally six kinds of numbers of poles be that example is described this.Can analyze from this example, three kinds of number of poles variable-pole winding that derive from this method can have multiple connection, wherein the 6Y/6Y/3Y connection of the 6Y/3Y/3Y connection of 15 lead-out wires and 12 lead-out wires, 6Y/6Y/3 delta connection, the former needs 5 of reversing switches or 6, the latter two need 6 or 7, reducing several than non-Pole-changing using phase-mixing winding, is more desirable.But compare with the level of general simplex winding double-speed motor 2Y/Y, 3 of the every extremely average lead-out wires of 2Y/ delta connection, 3/2 of reversing switch, particularly with 3Y/3Y and some special connection as ▲/3 of every extremely average lead-out wires of Y, the level that reversing switch is 1 is compared, and then also has big gap.Lead-out wire is many, and particularly reversing switch is many, not only increases the pole-changing equipment cost, has also reduced functional reliability.The existence of these shortcomings makes the simplex winding three-speed motor can not show a candle to the simplex winding double-speed motor and is widely used, so that also have to adopt double-iron core double winding pattern or single iron core double winding pattern in many occasions.Therefore, simplify the connection of simplex winding three-speed motor as far as possible, always born in mind constantly target with diligent pursuit by the people for one.
Task of the present invention is exactly to obtain a kind of more simple connection on above-mentioned three kinds of number of poles Pole-changing using phase-mixing windings, make three kinds of every extremely average lead-out wire numbers of number of poles arrive simplex winding double-speed motor level less, every extremely average required reversing switch is lower than 2Y/Y and 2Y/ delta connection level, near 3Y/3Y and
/ Y connection level, and match the different slots that is suitable for adopting this connection and count different poles and compare variable-pole winding.
Solution of the present invention is as follows: through suitably mating, require two kinds of numbers of poles in three kinds of numbers of poles to realize the reverse pole-conversion of similar 2Y/Y connection, only need 6 lead-out wires and 3 reversing switches with two and half windings by to become that the reversal connection series connection get final product (be easy meter along connecing parallel connection, corresponding to claiming the utmost point in parallel along connecing number of poles in parallel, the number of poles of connecting corresponding to reversal connection claims the utmost point of connecting); Also require these two kinds of numbers of poles and another number of poles (following promptly match) at the multi-channel parallel Pole-changing using phase-mixing of on number II half winding, realizing similar 3Y/3Y connection form with this name.These need will have the 3Y of three neutral points to number II half winding by Y in the above-mentioned 2Y/Y connection instead, and these three neutral points just can by the three-phase that the group alias adheres to another utmost point separately.In this case, another utmost point also just in time forms the 3Y connection, the lead-out wire end points that above-mentioned three neutral points are exactly this utmost point, and three neutral points of this utmost point 3Y are exactly utmost point lead-out wire end points in parallel, are usefulness each other, just in time form the 3Y/3Y connection on half winding II.As for to number I half winding, must as the 2Y/Y connection, be connected into one tunnel series connection, three open ends of this half winding are still drawn line end for the series connection utmost point.So, only need on the basis of 6 lead-out wires of two kinds of numbers of poles of original reverse pole-conversion each other, 3 reversing switches, to increase by 3 lead-out wires in passing and a mains switch just obtains another number of poles, so three kinds of numbers of poles altogether only need 9 lead-out wires and 4 reversing switches.Because the connection of another utmost point is 3Y, should be 4Y with the half winding I that is connected into Y along connecing the utmost point connection in parallel that is formed in parallel by the half winding II that is connected into 3Y, the series connection utmost point connection that is in series by this two and half windings reversal connection should be 3Y+Y, so three kinds of number of poles winding connection methods can be expressed as 3Y/4Y/3Y+Y.
Because two and half windings one are in parallel, one is series connection, and the same footmark mixed-phase component of two and half windings coil turn should be different with conductor cross-section, should be taken into account relevant requirements when choosing.
Be suitable for adopting the Pole-changing using phase-mixing winding of above-mentioned 3Y/4Y/3Y+Y connection, its three kinds of numbers of poles should be from realizing six kinds of number of poles-2p of Pole-changing using phase-mixing at same winding
1, 2p
2, 2p
3, 2p
4, 2p
5, 2p
6In choose, and wherein two kinds of numbers of poles should be got 2p simultaneously
1With 2p
6, or get 2p simultaneously
2With 2p
5Or get 2p simultaneously
3With 2p
4These six kinds of numbers of poles can be expressed as 2p with general formula
1=2p, 2p
2=(Z)/3-2p, 2p
3=(Z)/3+2p, 2p
4=(2Z)/3-2p, 2p
5=(2Z)/3+2p, 2p
6=Z-2p, Z is pole-changing conceptual design groove number (must be 6 multiple) in the formula, p is the natural number less than (Z)/12.In theory, the also available slot ripples number of poles displacement separately of any utmost point of these six kinds of numbers of poles.
Can match the Pole-changing using phase-mixing winding that much is suitable for adopting above-mentioned connection according to mentioned above principle.For example, when pole-changing conceptual design groove was counted Z=18, p＜(Z)/12=3/2, can only get p=1 was so can get 2p
1=2,2p
2=4,2p
3=8,2p
4=10,2p
5=14,2p
6=16, corresponding three kinds of numbers of poles can be 2,4,16,2,8,16,2,10,16,2,14,16,2,4,14,4,8,14,4,10,14,4,14,16,2,8,10,4,8,10,8,10,14,8,10,16.And for example, when Z=30, p＜(Z)/12=5/2 (p desirable 1,2), as get p=1, can get 2p
1=2,2p
2=8,2p
3=12,2p
4=18,2p
5=22,2p
6=28, corresponding three kinds of numbers of poles desirable 2,8,28,2,12,28 As get/p=2, can get 2p
1=4,2p
2=6,2p
3=14,2p
4=16 ,/2p
5=24,2p
6=26.Corresponding three kinds of numbers of poles desirable 4,6,26,4,14,26,4,16,26 ...When Z and p get other value, also can draw three kinds of numbers of poles of other different poles ratio.
Compared with the prior art, the present invention has following advantage:
(1), the required reversing switch of the present invention's three fast windings reduced a greater part ofly than general connection variable-pole winding, also reduce to some extent than Pole-changing using phase-mixing winding, required lead-out wire also arrives the lower limit of prior art less.
(2), the present invention's utmost point number of turn of connecting is the twice of the utmost point in parallel and another utmost point number of turn, differ multipole conversion far away-so be specially adapted to two kinds of approaching few utmost points and another as crane type load occasion, be used for replacing double-iron core double winding three-speed motor, except that can reducing the cost of motor own, also make the GD of this system
2Reduce significantly, thereby both reduced, shorten settling time again, raise labour productivity because of a large amount of energy consumptions in often starting, braking, the transient process that causes of reversing (this kind energy consumption generally account for total losses about 2/3rds).
(3), three kinds of number of poles matching principles according to the present invention, not only can draw three kinds of number of poles variable-pole winding that much are applicable to new connection, and can obtain under the different slots number according to six kinds of number of poles universal expression formulas and can realize six kinds of numbers of poles of Pole-changing using phase-mixing, and therefrom know 2p at same winding
1Five kinds of numbers of poles outside the utmost point come down to use respectively the result of (Z)/3 utmost point, (2Z)/3 utmost point and the Z utmost point modulation 2p utmost point, thereby can arrange according to 2p utmost point winding and directly draw all the other five kinds of number of poles windings arrangements, and to judge which kind of number of poles be with turning to respect to the 2p utmost point, and which kind of number of poles is a counter steer with respect to the 2p utmost point.
Description of drawings:
Fig. 1 is the 3Y/4Y/3Y+Y mode of connection: a) be winding diagram; B) be another utmost point switch connection; C) be utmost point switch connection in parallel; D) be series connection utmost point switch connection.
Below to get 2p
, 2p
, 2p
5When three kinds of numbers of poles and p get possible maximum three kinds of number of poles Pole-changing using phase-mixing windings be example and in conjunction with Fig. 1 the invention will be further described.
2p in this example
aWith 2p
bTwo kinds of numbers of poles are the reverse method pole-changing each other, this two kinds of numbers of poles and 2p
1Then belong to the commutation pole-changing between the utmost point.Count Z when pole-changing conceptual design groove and get 18,30,42,48,54,66,72 respectively, and when p gets possible maximum, 2/6/18 utmost point that three kinds of number of poles ultimate ratios will be respectively 2/4/14,4/6/24,6/8/34,6/10/38,8/10/44,10/12/54,10/14/58(does not comprise 24 grooves is because of three multipole proportions are difficult to realize the multi-channel parallel Pole-changing using phase-mixing; Do not comprise 36 grooves, 4/8/28 utmost point and 60 grooves, 8/12/48 utmost point, because of 4/6/24 extremely suitable with 2/4/14 utmost point of 18 grooves and 30 grooves respectively) yet.The corresponding three kinds of number of poles windings of each groove number are arranged as table 1 to shown in the table 7, wherein provide the arrangement of whole groove numbers except that 2/4/14 utmost point of 18 grooves and 4/6/24 utmost point winding of 30 grooves, and 1/3rd groove number is all only got in the several three kinds of number of poles windings arrangements of all the other grooves.2p in the table
1The utmost point number all adopts mutually lowercase, 2p
2The utmost point and 2p
5The utmost point number all adopts mutually capitalization.Find out the 2p of each groove number by the winding permutation table
2The utmost point and 2p
5The utmost point is reverse method pole-changing each other all, the two and 2p
1Then belong to the commutation pole-changing between the utmost point.According to belong to mutually with 18 groups of coil groups alias that draw to genus (three number letter represent that successively another utmost point, the utmost point in parallel, the series connection utmost point belong to mutually, represent two kinds to belonging to number I, II) mutually as Fig. 1 a) shown in.9 groups of coils to number II half winding among the figure all are three tunnel stars in parallel to three kinds of numbers of poles, to the per three groups of coils of 9 groups of coils of number I half winding to 2p
2With 2p
5The utmost point (two of reverse pole-conversion kinds of numbers of poles each other) say so one the tunnel series connection, to 2p
1The utmost point (another utmost point) is said and is then adhered to three-phase separately.Whole winding has 9 and draws line end-end points 1,2,3 and be 2p
1The utmost point (another utmost point) is drawn line end, and end points 4,5,6 is 2p
2The utmost point (utmost point in parallel) is drawn line end, and end points 7,8,9 is 2p
5The utmost point (the series connection utmost point) is drawn line end.When end points 1,2,3 connects power supply (Fig. 1 b), obtain 2p
1The 3Y connection of the utmost point (another utmost point) only needs a mains switch this moment.When end points 4,5,6 connects power supply, during end points 7,8,9 short circuits (Fig. 1 c), the 3Y of two and half windings and Y are obtained 2p by in parallel along connecing
2The 4Y connection of the utmost point (utmost point in parallel) needs a mains switch and a short switch this moment.When end points 7,8,9 connect power supply (Fig. 1 d), two and half windings were connected by reversal connection, obtain 2p
5The 3Y+Y connection of the utmost point (the series connection utmost point) also only needs a mains switch this moment.As seen three kinds of numbers of poles only need 9 lead-out wires altogether.4 reversing switches.Be not difficult to find out 2p
1The utmost point (another utmost point) and 2p
2The utmost point (utmost point in parallel) just in time forms on half winding II and is equivalent to get a kind of commutation pole-changing to genus 3Y/3Y connection, 2p
2The utmost point (utmost point in parallel) and 2p
5The utmost point (the series connection utmost point) forms on whole winding then that to change the reversal connection series connection be the reverse pole-conversion of feature along connecing parallel connection with two and half windings, and its 4Y/3Y+Y connection and general 2Y/Y connection are not without similarity.
When getting the winding practical number of slots is the twice that pole-changing conceptual design groove is counted Z, structure is reduced to bilayer by four layers, and (limit, two upper stratas that is about to former design groove embeds the odd bin at actual groove, and two lower floor limits embed the even bin at actual groove), and when getting span y=13 by practical number of slots, the corresponding three kinds of number of poles first-harmonics of each groove number and a kind of to another utmost point that belongs to half winding for getting by design groove Z(, design groove should be that slot ripples (only getting less than the general number of times of the practical number of slots) chording factor and the magnetic potential amplitude of (Z)/(^) determined is as shown in table 8.By general double speed variable-pole winding requirement-harmonic number (for first-harmonic) ν 〉=2 o'clock, amplitude was no more than 10%, and ν≤2 an o'clock amplitude is no more than 20%, and above-mentioned three fast variable-pole winding harmonic contents are removed some groove and counted 2p
5The utmost point be lower than 2 (the inferior amplitude in (Z)/3+p-Z) seems outside the height, other number of poles harmonic wave can think it is satisfactory basically.
Table 1 (Z=18)
Table 2 (Z=30)
Claims (2)
1, the Pole-changing using phase-mixing winding 3Y/4Y/3Y+Y connection of three kinds of numbers of poles of a kind of energy changing-over, it is identical that three kinds of numbers of poles of this winding are counted N by the equivalent utmost point phase groove of pole-changing conceptual design groove number, winding arrangement characteristics are identical, by can be divided into to number I with to two and half windings of number II to belonging to, (respectively organize coil by belonging to mutually and can being divided into 18 groups of coils with organizing the alias representative to genus, the group alias by each number of poles mutually number with to number forming), can realize the multi-channel parallel Pole-changing using phase-mixing, the invention is characterized in: require to have two kinds of numbers of poles reverse method pole-changing each other in three kinds of numbers of poles, these two kinds of numbers of poles (claim the utmost point in parallel corresponding to two and half windings along connecing number of poles in parallel, number of poles corresponding to two and half winding reversal connections series connection claims the utmost point of connecting) only require at the multi-channel parallel Pole-changing using phase-mixing of on half winding of number II, realizing similar 3Y/3Y connection form with another utmost point (following promptly match) in three kinds of numbers of poles with this name, when carrying out back panel wiring, need to belong to (or the utmost point in parallel belongs to mutually) to 9 groups of coils of number II half winding mutually by the series connection utmost point and be connected into three road parallel in planetary 3Y, its three neutral points should adhere to the three-phase of another utmost point separately by the group alias, to belong to mutually by the series connection utmost point to 9 groups of coils of number I half winding and be connected into one tunnel series connection, by series connection utmost point reversal connection series connection requirement two and half windings are linked up again, whole winding has 9 and draws line end, three closed circuit ends (i.e. three neutral points) to number II half winding are drawn line end for another utmost point, three end points that connect two and half windings are that the utmost point in parallel is drawn line end, three open ends to number I half winding are the line end of drawing of the series connection utmost point, when another utmost point lead-out wire termination power, obtain the 3Y connection of this utmost point, three neutral points of this 3Y are utmost point lead-out wire end points in parallel, at this moment only half winding II is utilized, but only need a mains switch, when utmost point lead-out wire termination power in parallel, when the series connection utmost point is drawn the line end short circuit, to the 3Y of number II half winding with to the Y of number I half winding by in parallel along connecing, obtain the 4Y connection of this utmost point, need a mains switch and a short switch this moment, when series connection utmost point lead-out wire termination power, be connected into 3Y to number II half winding be connected into one tunnel connected by reversal connection to number I half winding, obtain the 3Y+Y connection of this utmost point, the 3Y/4Y/3Y+Y connection of Xing Chenging like this, three kinds of numbers of poles only need 9 lead-out wires and 4 reversing switches altogether.
2, a kind of three kinds of number of poles Pole-changing using phase-mixing windings that are applicable to the described 3Y/4Y/3Y+Y connection of claim 1, comprise three kinds of number of poles Pole-changing using phase-mixing windings that are selected from 18 grooves 2,4,8,10,14,16 6 kind of number of poles, it is characterized in that: described three kinds of numbers of poles should be from realizing six kinds of number of poles-2p of Pole-changing using phase-mixing at same winding
1, 2p
2, 2p
3, 2p
4, 2p
5, 2p
6In choose, and wherein two kinds of numbers of poles should be got 2p simultaneously
1With 2p
6, or get 2p simultaneously
2With 2p
5, or get 2p simultaneously
3With 2p
4, these six kinds of numbers of poles can be expressed as 2p with general formula
1=2p, 2p
2=(Z)/3-2p, 2p
3=(Z)/3+2p ,/2p
4=(2Z)/3-2p, 2p
5=(2Z)/3+2p, 2p
6=Z-2p, Z is pole-changing conceptual design groove number (must be 6 multiple) in the formula, p is the natural number less than (Z)/12, the also available slot ripples number of poles displacement separately of any utmost point of these six kinds of numbers of poles.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 89105801 CN1025976C (en) | 1989-11-30 | 1989-11-30 | Three-speed miscible-phase pole-changing winding wiring method and pole-changing winding |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 89105801 CN1025976C (en) | 1989-11-30 | 1989-11-30 | Three-speed miscible-phase pole-changing winding wiring method and pole-changing winding |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1044740A true CN1044740A (en) | 1990-08-15 |
| CN1025976C CN1025976C (en) | 1994-09-21 |
Family
ID=4856449
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 89105801 Expired - Fee Related CN1025976C (en) | 1989-11-30 | 1989-11-30 | Three-speed miscible-phase pole-changing winding wiring method and pole-changing winding |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1025976C (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101212197B (en) * | 2006-12-27 | 2010-12-08 | 比亚迪股份有限公司 | AC motor system with variable number of pole pairs for electric automobile |
| CN101986531A (en) * | 2010-11-12 | 2011-03-16 | 武汉金路达电机有限公司 | Alternating-current pole-changing three-speed three-phase induction motor |
| CN103560631A (en) * | 2013-11-01 | 2014-02-05 | 景德镇市景德电机有限公司 | Low-rotation speed multiple-speed three-phase asynchronous motor |
-
1989
- 1989-11-30 CN CN 89105801 patent/CN1025976C/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101212197B (en) * | 2006-12-27 | 2010-12-08 | 比亚迪股份有限公司 | AC motor system with variable number of pole pairs for electric automobile |
| CN101986531A (en) * | 2010-11-12 | 2011-03-16 | 武汉金路达电机有限公司 | Alternating-current pole-changing three-speed three-phase induction motor |
| CN103560631A (en) * | 2013-11-01 | 2014-02-05 | 景德镇市景德电机有限公司 | Low-rotation speed multiple-speed three-phase asynchronous motor |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1025976C (en) | 1994-09-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN1304577A (en) | Single phase three speed motor with shared windings | |
| US2820938A (en) | Multi-speed alternating current motor | |
| CN1025976C (en) | Three-speed miscible-phase pole-changing winding wiring method and pole-changing winding | |
| CN102013776A (en) | Variable-speed three-phase asynchronous motor | |
| CN109802605A (en) | Method for controlling position-less sensor and device for long distance driver magneto | |
| US3875484A (en) | Travelling field electric motor with improved stator | |
| CN2481042Y (en) | Double-winding capacitance internal compansation motor | |
| CN2335298Y (en) | Inner compensation energy-saving motor | |
| CN104917351A (en) | Brushless doubly-fed generator | |
| CN1314186C (en) | Proper faction groove sinusoidal winding of equidistant synchronous generator | |
| CN1020834C (en) | Four tube three phase sine pulse width modulated frequency convertor | |
| CN1243402C (en) | Internal compensation method of A.C motor and its winding connection method | |
| CN1124421A (en) | Connecting method for changing single star-triangle into double star-triangle in ac motor winding | |
| CN2186436Y (en) | Balance transformer with triphase change to two-phase | |
| DD293469A5 (en) | METHOD FOR SYNCHRONIZING SEVERAL COMMONLY OPERATED BROKEN INPUT CURRENT | |
| CN108900022A (en) | Score pole road is than lap wound partial unit connecting method | |
| CN103475111B (en) | A kind of motor | |
| CN1041846A (en) | Three-phase is imported the transformer of single-phase output | |
| CN2283944Y (en) | Single-phase and three-phase universal asynchronous motor | |
| CN2586286Y (en) | A.C. brushless double-feedback dynamo | |
| CN2097469U (en) | High-efficiency three-phase multi-speed asynchronous motor | |
| CN2366955Y (en) | Hexagonal,six window, variable phase and variable frequency transformer | |
| CN1039928A (en) | A kind of three-phase saturation electric reactor of double-iron core | |
| SU949725A1 (en) | Three-phase controllable transformer device | |
| CN2366956Y (en) | Hexagonal, 18 window, variable phase and variable frequency transformer |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |