CA1201749A - Single phase four pole/six pole motor - Google Patents
Single phase four pole/six pole motorInfo
- Publication number
- CA1201749A CA1201749A CA000441557A CA441557A CA1201749A CA 1201749 A CA1201749 A CA 1201749A CA 000441557 A CA000441557 A CA 000441557A CA 441557 A CA441557 A CA 441557A CA 1201749 A CA1201749 A CA 1201749A
- Authority
- CA
- Canada
- Prior art keywords
- coils
- auxiliary
- pole
- coil
- electric motor
- 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.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P25/00—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details
- H02P25/16—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the circuit arrangement or by the kind of wiring
- H02P25/18—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the circuit arrangement or by the kind of wiring with arrangements for switching the windings, e.g. with mechanical switches or relays
- H02P25/20—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the circuit arrangement or by the kind of wiring with arrangements for switching the windings, e.g. with mechanical switches or relays for pole-changing
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K3/00—Details of windings
Abstract
ABSTRACT OF THE DISCLOSURE
A single phase alternating current electric motor is provided with a main stator winding having two coil groups each including the series connection of three coils. These coil groups can be connected in series for six pole operation and in parallel for four pole opera-tion. The coils are approximately equally spaced around the periphery of the machine but are not of equal numbers of turns. The two coil groups are identically wound and spaced 180 mechanical degrees apart. One coil of each group has more turns and a greater span than the other two coils.
A single phase alternating current electric motor is provided with a main stator winding having two coil groups each including the series connection of three coils. These coil groups can be connected in series for six pole operation and in parallel for four pole opera-tion. The coils are approximately equally spaced around the periphery of the machine but are not of equal numbers of turns. The two coil groups are identically wound and spaced 180 mechanical degrees apart. One coil of each group has more turns and a greater span than the other two coils.
Description
1 50,34 SINGLE PH~SE FOUR POLE/SIX POLE MOTOR
B~CKG~OUND OF THE INV~N'l'ION
This invention relates ~o pole changing J single phase alterna~ing current rotary electrîc machines, and more particularly to induction motors having stator wind-ings which are capable o~ alternatively being connectedfor four pole and six pole operation.
High efficiency heat pltmps require high effi-ciency fan and blower motors having multispeed capabil-ities, Conventional multispeed motors employ an ex~ra winding that effectively reduces the operating flux level which is equivalent to voltage reduction in a polyphase motor. The resulting speed-torque curve of the motor is reduced and the motor operates at reduced speed determined by the intersection of the blower or fan speed-~orque characteristic with the motor sp~eed-torque characteristic.
In order to get significant speed reduction, the motor then operates at a high value of slip which leads to very poor efficiency. Since the blower motor of a high capac-ity heat pump may operate at low spPed for about 75% of the pump's operating hours J ~he use of a two speed blower motor based on a high slippage ai the lower speed is un-desirable.
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~2~:3~
B~CKG~OUND OF THE INV~N'l'ION
This invention relates ~o pole changing J single phase alterna~ing current rotary electrîc machines, and more particularly to induction motors having stator wind-ings which are capable o~ alternatively being connectedfor four pole and six pole operation.
High efficiency heat pltmps require high effi-ciency fan and blower motors having multispeed capabil-ities, Conventional multispeed motors employ an ex~ra winding that effectively reduces the operating flux level which is equivalent to voltage reduction in a polyphase motor. The resulting speed-torque curve of the motor is reduced and the motor operates at reduced speed determined by the intersection of the blower or fan speed-~orque characteristic with the motor sp~eed-torque characteristic.
In order to get significant speed reduction, the motor then operates at a high value of slip which leads to very poor efficiency. Since the blower motor of a high capac-ity heat pump may operate at low spPed for about 75% of the pump's operating hours J ~he use of a two speed blower motor based on a high slippage ai the lower speed is un-desirable.
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~2~:3~
2 50,344 Pole changing alternating current electric motors have been developed t:o provide for multispeed operation without high slippage values. For example, U.S.
Patent No. 3,233,160 issued February 1, 1966 to Rawcliffe discloses a single phase alternating current pole changing motor having a stator wnding arrangement which includes two windings for connection together to a single phase alternating current supply to provide a running field for the motor wherein each winding is wound or a first pole number and has winding parts arranged for alternative connection in the circuit accc,rding to a method of pole amplitude modulation, thereby providing second and third pole numbers together in each winding considered indepen-dently. An additional stator winding is provided for connection to the single phase alternating current supply through a phase shifting means, to provide a starting field for the motor. The first two windings are physical-ly disposed for elimination of the third pole number from the running field.
U.S. Patent No, 3,619,730 îssued November 9, 1971 to Broadway et al., discloses a four pole/six pole machine which utilizes a pole amplitude modulation tech-nique. The Broadway et al. patent employs our stator field coils in the main winding and favors a four pole field. In addition, Broadway Pt al. shows only a four pole (consequent pole~ auxiliary ~inding, which would be used only in the four pole connection and would be dis-connected when running as a six pole machine. Therefore, the machine could be started only in the four pole mode.
The present invention utilizes six field coils in the main winding of a four pole/six pole single phase motor, and can be started when connected for either pole number.
SUMMARY OF THE INVENTION
A single phase alternating current electric motor constructed in accordance with this invention com-prises: a main stator winding .including two identical coil group~ spaced 180 mechanical degrees apart and each
Patent No. 3,233,160 issued February 1, 1966 to Rawcliffe discloses a single phase alternating current pole changing motor having a stator wnding arrangement which includes two windings for connection together to a single phase alternating current supply to provide a running field for the motor wherein each winding is wound or a first pole number and has winding parts arranged for alternative connection in the circuit accc,rding to a method of pole amplitude modulation, thereby providing second and third pole numbers together in each winding considered indepen-dently. An additional stator winding is provided for connection to the single phase alternating current supply through a phase shifting means, to provide a starting field for the motor. The first two windings are physical-ly disposed for elimination of the third pole number from the running field.
U.S. Patent No, 3,619,730 îssued November 9, 1971 to Broadway et al., discloses a four pole/six pole machine which utilizes a pole amplitude modulation tech-nique. The Broadway et al. patent employs our stator field coils in the main winding and favors a four pole field. In addition, Broadway Pt al. shows only a four pole (consequent pole~ auxiliary ~inding, which would be used only in the four pole connection and would be dis-connected when running as a six pole machine. Therefore, the machine could be started only in the four pole mode.
The present invention utilizes six field coils in the main winding of a four pole/six pole single phase motor, and can be started when connected for either pole number.
SUMMARY OF THE INVENTION
A single phase alternating current electric motor constructed in accordance with this invention com-prises: a main stator winding .including two identical coil group~ spaced 180 mechanical degrees apart and each
3 50,3~4 having three series connected coils, whQrein all six coils are approximately equally spaGed around the motor peri phery and at least two of the coils have an equal number of turns which difers from the number of turns of the other coil; means for connect:iny the two main stator winding coil groups for six pole motor operation; and means for connecting the two main stator winding coil groups for four pole motor operation, wher~in one o the coil groups has a reverse polarity with respec~ to its connection for six pole operati.on. For example, the coil groups may form six poles when connected in series and four poles when connected in parallel. Several auxiliary winding configurations can be connected in series wi-th a phase shifting means, such as a capacitor, to the motor power source. In one embodim~ent, the auxiliary stator winding comprises two identical coil groups ~paced 180 mechanical degrees apart and each having three series connected coils wherein all six auxiliary coils are ap-proximately e~ually spaced aroun~ the motor periphery and displaced 90 electrical degrees, on a six pole basis, from the main stator winding coils, with at least two of the - six auxiliary coils having an equal number o turns which differs from the number of turns in the other auxiliary coils. These auxiliary windirlg coil groups can be al-ternatively connected for six or four pole operation respectively. Alternatively, two separate auxiliary windings can be wound using the slot space not used by the main winding.
BRIEF DESCRIPTION OF THE DRAWINGS
Eigure 1 is a schematic diagram of a rnain stator windillg circuit having two ungraded coil groups connected in series in accordance with one embodiment of this inven tion;
Eigure ~ is a schema~tic diagram of the stator winding of ~igure 1 connected in parallel in accordance with this invention;
BRIEF DESCRIPTION OF THE DRAWINGS
Eigure 1 is a schematic diagram of a rnain stator windillg circuit having two ungraded coil groups connected in series in accordance with one embodiment of this inven tion;
Eigure ~ is a schema~tic diagram of the stator winding of ~igure 1 connected in parallel in accordance with this invention;
4 50,344 Fi~ure 3 i5 a wiring diagram of a 36 slot motor showing ~he main stator winding connec~ed for six pole operation in accordance with one embodiment of this inven~
tion;
S Figure 4 is a maynet:omotive force diagram pro-duced by the winding arrangement of Figure 3;
Figure S is a wiring diagram of a 36 slot elec-tric motor showing the main s1ator winding connected or four pole operation in accordance with this inv~ntion;
'``10 Figure 6 is a magnetomotive force ~F diagram produced by the winding of Figure 5;
Figure 7 is a schematic diagram of the stator circuit of a motor constructed in accordance with one embodiment of this invention;
Eigure 8 is a schematic diagram of the stator circuit of ~n alternative emhodiment of this invention;
Figure 9 is a schematic diagram of the stator circuit of another alternative embodiment of this inven-tion; and Figure 10 is a speed-torque curve for an embodi-ment of this invention employing a single ixed pole number auxiliary winding.
DESCRIPTION OF THE PRE~ERRED EM~ODIMENTS
A four pole/six pole electric motor constructed in accordance with the preferred embodiment of this inven-tion uses a single main and a single auxiliary windin~.
The main stator winding includes six pole coils which are approximately equally spaced around the machine periphery.
However, all coils do not have the same span and number of turns. Re~erring to the drawings, Fi~ure 1 is a schematic diagram of the main stator winding of a motor constructed in accordance with this invention. Two coil groups, 10 and 12 are shown to be connected in series between a pair of line power t~rminals, Ll and L2. Coil group 10 com-prises the series connection of coils 14, 16 and 18, while coil ~roup 12 comprises a seri~s connection of coils 20, 22 and 24.~ The series connection of coil groups 10 and 12 results in 5iX pole operation of the motor.
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S 50,344 Fi~ure 2 is a schematic diagram of the stator winding of Figure 1 showing the coil groups 10 and 12 connected in parallel between line terminals Ll and L2 for four pole motor operation. In this connection, the polar-ity of coil group 12 is reversed with respect to theconnection of Figure 1.
~ igure 3 is a wiring diagram showing the slot loading of a 36 slot stator having the main stator winding connected in serias or six pole operation as in Figure 1.
In this Figure, the dots indicate instantaneous current flow out of the sheet, while the X's indicate instantan aous current flow into the sheet. Coils 16 and 22 are designated as primary coils, al.e disposed 180 mechanical de~rees apart and are identically wound to include five coil elements, the largest of which has a coil throw of 11 slots. The remaining four coils are designated as second-ary coils with each having three coil elemPnts, the larg-est of which has a coil throw of 7 slots. These smaller coils are disposed in such a way around the periphery of the machine, that their centers are six slots rom each othPr. This corresponds to 180 electrical degrees separa-tion. The span of the primary coils should be as nearly e~ual to two pole pitches, of~ the six pole field, as possible within any constraints imposed by the number of slots available. In addition, the secondary coils should span one pole pitch, or be one or two slots wider than one pole pitch of the six pole field.
The preferred embodiment auxiliary winding has the same structure as the main stator winding, although it may have a different number of t:urns per coil and be wound with a different size wire. It is displaced 3 slots from the main winding so that the fundamental six pole fl~x distributions of the main and auxiliary windin~s are in space quadrature. However, this is not a necessary con~
straint, as non quadrature wincling placement in the six pole configuration would be permissible.
:
6 50,344 The auxiliary winding comprises ~wo coil groups, each including the series connection of a primary coil and ~wo secondary coils. These coils have the same rela~ive angular position around the mo1or periphery as the coils of the main stator winding. That is, the auxiliary wind-ing coils are spaced 90 electrical degrees apart with each primary auxiliary coil being centered between two secon-dary auxiliary coils of the same group. The auxiliary winding coil groups are spaced l80 mechanical degrees apart. Within each group, the primary auxiliary coil has more turns and a larger span than each of the secondary coils. As in the main winding, the primary auxiliary coils should span about two pole pitches of the six pole field, within any constraints imposed by th~ number of slots available. The secon~ary auxiliary coils should span about one pole pitch, or be one or two slots wider than ona pole pitch of the six pole fielcl. Each primary auxiliary coil should havP about l-2/3 times the number of turns in each secondary auxiliary coil.
In the winding arrangement shown in Figure 3, the number of conductors in eac:h coil side are identical.
Thereore, primary coil6 16 and 22 have l-2/3 times ~s many turns as secondary coils 14, 18, 20 and 24, and each primary coil is centered between the two secondary coils of the same group. In other en~odiments, the position of the primary winding may be interchanged with that of either secondary winding. With the Figure 3 winding distribution, magnetomotive force 26 of Figure 4 includes a six pole fundamental 28 with a signiicant two pole subharmonic 30. In other embodiments, it is not necessary for the number of conductors in each coil side to be identical since ~rading of the coils would be permissible.
Figure 5 is a wiring diagram of the main stat~r winding of Figure 4 which is connectecl in accordance with Figure 2 for four pole operation. It can be seen that half of the coils are reversed relative to their connec tion for s~x poles as in Figure 4. The resulting magneto-7 50,344 motive force 32 of Figure 6 shows a dominant four pole field 34 and a smaller 8 pole field 36. In this embodi ment, the auxiliary winding t~roups would al~o be connectetl in parallel to form a four pole field. Since the auxil-iary winding is displaced three slots from the main wind-ing, the two four pole field,~ are no longer in space t~uadrature, the angle now being 60 electrical degrees. It can be shown that if the current; in this auxiliary winding could be made to lead the curre-nt in the main winding by 120 electrical degrees, the fc>ur pole field would have only a forward rotating component. By appropriate selec-tion of an auxiliary ~inding capacitor, this is possible at one operating load. I f the two currents are in t~uadra-ture, the four pole field would contain both forward and backward rotatingtomponents.
Figure 7 is a schemat:ic diagram constructed in accordance with this invention which is capable of four pole or 5ix pole operation. For six pole operation, main stator winding coil groups lO and 12 are connected in series between line terminals Ll and L2 through the cio sure of switch Sl. Similarly, auxiliary stator winding coil groups 38 and 40 are connec:ted in series wi~h capaci-tor Cl and between line terminals Ll and L2 through the closure of switch S4. Remaining switches S2, 53, S5 and S6 remain open or six pole operation. For four pol~
operation, switches Sl and S4 are opened, while switches S2, S3, S5 and S5 are closed. This connects main stator winding coil groups lO and 12 i!n parallel With each other between line terminals Ll and L2, while auxiliary stator winding coil groups 38 and 34 are connected in parallel with each other and in series wiLth capacitor C2 to form an auxiliary circuit which is connected across line terminals Ll and L2.
Figure 8 shows an alternative stator winding circuit diagram which utilizes a single capacitor C3 in series with the auxiliary winding. In this embodiment, six pole operation is again accomplished through the 3~2q~7~a 8 50,344 closure of switches S1 and S4 while the other switches remain open. Four pole operatîon is accomplished through the reversal of all switches. Fi~ure 9 shows another alternative embodiment stator circuit wherein switches S1, S2 and S3 are again used to connect main stator winding coil groups 10 and 12 in series or parallel for six pole or four pole operation respec:tively. However, separate non~pole changing auxiliary windings 42 and 44 have been provided. Auxiliary stator winding 42 would be wound for 6 poles and is connected in series with capacitor C4 through switch S7 for 6 pole operation, while auxiliary stator winding 44 would be wound ~or four poles and con-nected in series with capacitor C5 through S8 for four pole operation. The embodiment illustrated by Figure 9 can also be modified to eliminate switch S8, capacitor C5 and auxiliary stator coil 44 thereby leaving a single six pole auxiliary stator coil 42. In this modified embodi-ment, auxiliary stator coil 42 would be connected between line terminals Ll and L2 during both four pole and six pole operation. With this modified ambodiment, the speed-- torque characteristics of Figure 10 are obtained. Curve 46 represents the four pole speed-torque characteristic while curve 48 represents the six pole speed-torque char-acteristic. A typical fan blower load characteristic is shown as curve 50. It should be apparent to those skilled in the art that thi~ motor can only be started as a 5iX
pole motor since the four pole speed v~rsus torque charac--teristic goes to zero at 0 rpm.
The distribution actors as exemplified by the total effective series conductors have been computed for the six pole and four pole winding arrangements of Figures 3 and 5. In that embodiment, each coil side element has an identical number of conductors. If this number of conductors is designated as Nc, the six pole winding has a total of 44 Nc series conductors. Because of the distrib-uted ~ature of these conductors in the six pole ield, the effective ~umber o series conductors is 35.53 Nc, which '~;9~ 7'~3 g 5~,3~4 l~ads to a distribution factor of 0.8075. The four pole confiyuration has 22 N s~ries conductors. The efectiVe number of series conductors in this case is 14.70 N~ for a distribution factor of 0.6683. For this winding configur-ation, the ratio of the magnet:ic flux density in the sixpole field to the magnetic flux density in the four pole field is 0.6206. The torque capability o~ the machine varies approximately as the square of the ~lux ~ensi~y for a given slip. Thus the six pole torque capability would be 38.5% of thak of the four pole machine. Blower load torque at the six pole speecl would be approximately 4~9 that of the ~lower load torque at the four pole speed or 44.~%.
Although the present invention has been de-scribed in detail in terms of its preferred embodiments, it will be apparent to those skilled in the art tha various changes or modificat:ions may be made without departing from the invention. For e~ample, the main stator winding coil groups 10 and 12 can be connected i~
either sries or parallel to obtain both four and six pole operation. Table I lists the! pos~ible connection con-figurations.
TABLE I
Stator Winding Configurations Six Pole F~ur Pole Configuration Group Connections - Group Connections 1 10 and 12 in series10 and 12 in parallel ~1~ reversed) 2 10 and 12 in seri.es 10 and 12 in series (12 reversed) 3 10 and 12 in parallel 10 and 12 in series (12 reversed) 4 10 and 12 in parELllel 10 and 12 in parallel (12 reversed) >7~
tion;
S Figure 4 is a maynet:omotive force diagram pro-duced by the winding arrangement of Figure 3;
Figure S is a wiring diagram of a 36 slot elec-tric motor showing the main s1ator winding connected or four pole operation in accordance with this inv~ntion;
'``10 Figure 6 is a magnetomotive force ~F diagram produced by the winding of Figure 5;
Figure 7 is a schematic diagram of the stator circuit of a motor constructed in accordance with one embodiment of this invention;
Eigure 8 is a schematic diagram of the stator circuit of ~n alternative emhodiment of this invention;
Figure 9 is a schematic diagram of the stator circuit of another alternative embodiment of this inven-tion; and Figure 10 is a speed-torque curve for an embodi-ment of this invention employing a single ixed pole number auxiliary winding.
DESCRIPTION OF THE PRE~ERRED EM~ODIMENTS
A four pole/six pole electric motor constructed in accordance with the preferred embodiment of this inven-tion uses a single main and a single auxiliary windin~.
The main stator winding includes six pole coils which are approximately equally spaced around the machine periphery.
However, all coils do not have the same span and number of turns. Re~erring to the drawings, Fi~ure 1 is a schematic diagram of the main stator winding of a motor constructed in accordance with this invention. Two coil groups, 10 and 12 are shown to be connected in series between a pair of line power t~rminals, Ll and L2. Coil group 10 com-prises the series connection of coils 14, 16 and 18, while coil ~roup 12 comprises a seri~s connection of coils 20, 22 and 24.~ The series connection of coil groups 10 and 12 results in 5iX pole operation of the motor.
t~
S 50,344 Fi~ure 2 is a schematic diagram of the stator winding of Figure 1 showing the coil groups 10 and 12 connected in parallel between line terminals Ll and L2 for four pole motor operation. In this connection, the polar-ity of coil group 12 is reversed with respect to theconnection of Figure 1.
~ igure 3 is a wiring diagram showing the slot loading of a 36 slot stator having the main stator winding connected in serias or six pole operation as in Figure 1.
In this Figure, the dots indicate instantaneous current flow out of the sheet, while the X's indicate instantan aous current flow into the sheet. Coils 16 and 22 are designated as primary coils, al.e disposed 180 mechanical de~rees apart and are identically wound to include five coil elements, the largest of which has a coil throw of 11 slots. The remaining four coils are designated as second-ary coils with each having three coil elemPnts, the larg-est of which has a coil throw of 7 slots. These smaller coils are disposed in such a way around the periphery of the machine, that their centers are six slots rom each othPr. This corresponds to 180 electrical degrees separa-tion. The span of the primary coils should be as nearly e~ual to two pole pitches, of~ the six pole field, as possible within any constraints imposed by the number of slots available. In addition, the secondary coils should span one pole pitch, or be one or two slots wider than one pole pitch of the six pole field.
The preferred embodiment auxiliary winding has the same structure as the main stator winding, although it may have a different number of t:urns per coil and be wound with a different size wire. It is displaced 3 slots from the main winding so that the fundamental six pole fl~x distributions of the main and auxiliary windin~s are in space quadrature. However, this is not a necessary con~
straint, as non quadrature wincling placement in the six pole configuration would be permissible.
:
6 50,344 The auxiliary winding comprises ~wo coil groups, each including the series connection of a primary coil and ~wo secondary coils. These coils have the same rela~ive angular position around the mo1or periphery as the coils of the main stator winding. That is, the auxiliary wind-ing coils are spaced 90 electrical degrees apart with each primary auxiliary coil being centered between two secon-dary auxiliary coils of the same group. The auxiliary winding coil groups are spaced l80 mechanical degrees apart. Within each group, the primary auxiliary coil has more turns and a larger span than each of the secondary coils. As in the main winding, the primary auxiliary coils should span about two pole pitches of the six pole field, within any constraints imposed by th~ number of slots available. The secon~ary auxiliary coils should span about one pole pitch, or be one or two slots wider than ona pole pitch of the six pole fielcl. Each primary auxiliary coil should havP about l-2/3 times the number of turns in each secondary auxiliary coil.
In the winding arrangement shown in Figure 3, the number of conductors in eac:h coil side are identical.
Thereore, primary coil6 16 and 22 have l-2/3 times ~s many turns as secondary coils 14, 18, 20 and 24, and each primary coil is centered between the two secondary coils of the same group. In other en~odiments, the position of the primary winding may be interchanged with that of either secondary winding. With the Figure 3 winding distribution, magnetomotive force 26 of Figure 4 includes a six pole fundamental 28 with a signiicant two pole subharmonic 30. In other embodiments, it is not necessary for the number of conductors in each coil side to be identical since ~rading of the coils would be permissible.
Figure 5 is a wiring diagram of the main stat~r winding of Figure 4 which is connectecl in accordance with Figure 2 for four pole operation. It can be seen that half of the coils are reversed relative to their connec tion for s~x poles as in Figure 4. The resulting magneto-7 50,344 motive force 32 of Figure 6 shows a dominant four pole field 34 and a smaller 8 pole field 36. In this embodi ment, the auxiliary winding t~roups would al~o be connectetl in parallel to form a four pole field. Since the auxil-iary winding is displaced three slots from the main wind-ing, the two four pole field,~ are no longer in space t~uadrature, the angle now being 60 electrical degrees. It can be shown that if the current; in this auxiliary winding could be made to lead the curre-nt in the main winding by 120 electrical degrees, the fc>ur pole field would have only a forward rotating component. By appropriate selec-tion of an auxiliary ~inding capacitor, this is possible at one operating load. I f the two currents are in t~uadra-ture, the four pole field would contain both forward and backward rotatingtomponents.
Figure 7 is a schemat:ic diagram constructed in accordance with this invention which is capable of four pole or 5ix pole operation. For six pole operation, main stator winding coil groups lO and 12 are connected in series between line terminals Ll and L2 through the cio sure of switch Sl. Similarly, auxiliary stator winding coil groups 38 and 40 are connec:ted in series wi~h capaci-tor Cl and between line terminals Ll and L2 through the closure of switch S4. Remaining switches S2, 53, S5 and S6 remain open or six pole operation. For four pol~
operation, switches Sl and S4 are opened, while switches S2, S3, S5 and S5 are closed. This connects main stator winding coil groups lO and 12 i!n parallel With each other between line terminals Ll and L2, while auxiliary stator winding coil groups 38 and 34 are connected in parallel with each other and in series wiLth capacitor C2 to form an auxiliary circuit which is connected across line terminals Ll and L2.
Figure 8 shows an alternative stator winding circuit diagram which utilizes a single capacitor C3 in series with the auxiliary winding. In this embodiment, six pole operation is again accomplished through the 3~2q~7~a 8 50,344 closure of switches S1 and S4 while the other switches remain open. Four pole operatîon is accomplished through the reversal of all switches. Fi~ure 9 shows another alternative embodiment stator circuit wherein switches S1, S2 and S3 are again used to connect main stator winding coil groups 10 and 12 in series or parallel for six pole or four pole operation respec:tively. However, separate non~pole changing auxiliary windings 42 and 44 have been provided. Auxiliary stator winding 42 would be wound for 6 poles and is connected in series with capacitor C4 through switch S7 for 6 pole operation, while auxiliary stator winding 44 would be wound ~or four poles and con-nected in series with capacitor C5 through S8 for four pole operation. The embodiment illustrated by Figure 9 can also be modified to eliminate switch S8, capacitor C5 and auxiliary stator coil 44 thereby leaving a single six pole auxiliary stator coil 42. In this modified embodi-ment, auxiliary stator coil 42 would be connected between line terminals Ll and L2 during both four pole and six pole operation. With this modified ambodiment, the speed-- torque characteristics of Figure 10 are obtained. Curve 46 represents the four pole speed-torque characteristic while curve 48 represents the six pole speed-torque char-acteristic. A typical fan blower load characteristic is shown as curve 50. It should be apparent to those skilled in the art that thi~ motor can only be started as a 5iX
pole motor since the four pole speed v~rsus torque charac--teristic goes to zero at 0 rpm.
The distribution actors as exemplified by the total effective series conductors have been computed for the six pole and four pole winding arrangements of Figures 3 and 5. In that embodiment, each coil side element has an identical number of conductors. If this number of conductors is designated as Nc, the six pole winding has a total of 44 Nc series conductors. Because of the distrib-uted ~ature of these conductors in the six pole ield, the effective ~umber o series conductors is 35.53 Nc, which '~;9~ 7'~3 g 5~,3~4 l~ads to a distribution factor of 0.8075. The four pole confiyuration has 22 N s~ries conductors. The efectiVe number of series conductors in this case is 14.70 N~ for a distribution factor of 0.6683. For this winding configur-ation, the ratio of the magnet:ic flux density in the sixpole field to the magnetic flux density in the four pole field is 0.6206. The torque capability o~ the machine varies approximately as the square of the ~lux ~ensi~y for a given slip. Thus the six pole torque capability would be 38.5% of thak of the four pole machine. Blower load torque at the six pole speecl would be approximately 4~9 that of the ~lower load torque at the four pole speed or 44.~%.
Although the present invention has been de-scribed in detail in terms of its preferred embodiments, it will be apparent to those skilled in the art tha various changes or modificat:ions may be made without departing from the invention. For e~ample, the main stator winding coil groups 10 and 12 can be connected i~
either sries or parallel to obtain both four and six pole operation. Table I lists the! pos~ible connection con-figurations.
TABLE I
Stator Winding Configurations Six Pole F~ur Pole Configuration Group Connections - Group Connections 1 10 and 12 in series10 and 12 in parallel ~1~ reversed) 2 10 and 12 in seri.es 10 and 12 in series (12 reversed) 3 10 and 12 in parallel 10 and 12 in series (12 reversed) 4 10 and 12 in parELllel 10 and 12 in parallel (12 reversed) >7~
5~,34~
It should be understood that wherever coil group 12 is shown to be connected for rever~s~d polari~y in Table I, it could be replaced by coil group 10. This would cause a reversal of rotation of the machine. In addition, the main and auxiliary windings need not be wound in a ~uadra-ture relationship since an external phase shifting device such as a capacitor could be used. It is therefore in-tended that the appended claims cover all such changes or modifications that fall within the scope of the invention.
It should be understood that wherever coil group 12 is shown to be connected for rever~s~d polari~y in Table I, it could be replaced by coil group 10. This would cause a reversal of rotation of the machine. In addition, the main and auxiliary windings need not be wound in a ~uadra-ture relationship since an external phase shifting device such as a capacitor could be used. It is therefore in-tended that the appended claims cover all such changes or modifications that fall within the scope of the invention.
Claims (26)
1. A single phase alternating current electric motor comprising:
a main stator winding wound to pass through a plurality of uniformly spaced slots in a stator and including two identical coil groups each having three series connected coils wherein all six coils are approximately equally spaced around the motor periphery, corresponding coils in each of said coil groups are spaced 180 mechanical degrees apart, and a first coil in each of said coil groups has a number of turns which differs from the number of turns of the other coils;
means for connecting said two coil groups to form six poles for six pole motor operation; and means for connecting said two coil groups to form four poles for four pole motor operation, wherein one of said coil groups has a reversed polarity with respect to its connection for six pole operation.
a main stator winding wound to pass through a plurality of uniformly spaced slots in a stator and including two identical coil groups each having three series connected coils wherein all six coils are approximately equally spaced around the motor periphery, corresponding coils in each of said coil groups are spaced 180 mechanical degrees apart, and a first coil in each of said coil groups has a number of turns which differs from the number of turns of the other coils;
means for connecting said two coil groups to form six poles for six pole motor operation; and means for connecting said two coil groups to form four poles for four pole motor operation, wherein one of said coil groups has a reversed polarity with respect to its connection for six pole operation.
2. An electric motor as recited in claim 1, wherein each coil group of said main stator winding com-prises:
a primary coil; and two secondary coils, wherein said primary coil has more turns and a larger span than said secondary coils.
a primary coil; and two secondary coils, wherein said primary coil has more turns and a larger span than said secondary coils.
3. An electric motor as recited in claim 2, wherein the span of each of said primary coils is about two pole pitches and the span of each of said secondary coils is about one pole pitch.
4. An electric motor as recited in claim 2, wherein said primary coils are centered between said secondary coils of the same coil group.
5. An electric motor as recited in claim 2, wherein the number of turns in each of said primary coils is approximately 1-2/3 times the number of turns in each of said secondary coils.
6. An electric motor as recited in claim 1, further comprising:
an auxiliary stator winding wound to pass through said uniformly spaced slots in said stator and including two identical coil groups each having three series connected coils wherein all six auxiliary coils are equally spaced around the motor periphery with corresponding coils in each of said auxiliary winding coil groups being spaced 180 mechanical degrees apart and with at least two of said six auxiliary coils having an equal number of turns which differs from the number of turns in the other auxiliary coils;
a capacitor;
means for connecting said two auxiliary coil groups to form six poles and in series with said capacitor for six pole motor operation.
an auxiliary stator winding wound to pass through said uniformly spaced slots in said stator and including two identical coil groups each having three series connected coils wherein all six auxiliary coils are equally spaced around the motor periphery with corresponding coils in each of said auxiliary winding coil groups being spaced 180 mechanical degrees apart and with at least two of said six auxiliary coils having an equal number of turns which differs from the number of turns in the other auxiliary coils;
a capacitor;
means for connecting said two auxiliary coil groups to form six poles and in series with said capacitor for six pole motor operation.
7. An electric motor as recited in claim 6, wherein each coil group of said auxiliary stator winding comprises:
a primary auxiliary coil; and two secondary auxiliary coils, wherein said primary auxiliary coil has more turns and a larger span than said secondary auxiliary coils.
a primary auxiliary coil; and two secondary auxiliary coils, wherein said primary auxiliary coil has more turns and a larger span than said secondary auxiliary coils.
8. An electric motor as recited in claim 7, wherein the span of each of said primary auxiliary coils is about two pole pitches and the span of each of said secondary auxiliary coils is about one pole pitch.
9. An electric motor as recited in claim 7, wherein said primary auxiliary coils are centered between said secondary auxiliary coils of the same coil group.
10. An electric motor as recited in claim 7, wherein the number of turns at each of said primary auxil-iary coils is approximately 1-2/3 times the number of turns in each of said secondary auxiliary coils.
11. An electric motor as recited in claim 6, further comprising:
means for connecting said two auxiliary coil groups to form four poles and in series with said capaci-tor for four pole operation, wherein one of said auxiliary coil groups has a reversed polarity with respect to its connection for six pole operation.
means for connecting said two auxiliary coil groups to form four poles and in series with said capaci-tor for four pole operation, wherein one of said auxiliary coil groups has a reversed polarity with respect to its connection for six pole operation.
12. An electric motor as recited in claim 6, further comprising:
a second capacitor; and means for connecting said two auxiliary coil groups to form four poles in series with second capacitor for four pole operation, wherein one of said auxiliary coil groups has a reversed polarity with respect to its connection for six pole operation.
a second capacitor; and means for connecting said two auxiliary coil groups to form four poles in series with second capacitor for four pole operation, wherein one of said auxiliary coil groups has a reversed polarity with respect to its connection for six pole operation.
13. An electric motor as recited in claim 1, further comprising:
a first capacitor;
a four pole auxiliary winding displaced 90 electrical degrees from said main stator winding, when connected to form four poles, and connected in series with said first capacitor to form a first auxiliary circuit;
a second capacitor;
a six pole auxiliary winding displaced 90 elec-trical degrees from said main stator winding, when con-nected to form six poles, and connected in series with said second capacitor to form a second auxiliary circuit;
and means for alternatively connecting one of said first and second auxiliary circuits in parallel with said main stator winding.
a first capacitor;
a four pole auxiliary winding displaced 90 electrical degrees from said main stator winding, when connected to form four poles, and connected in series with said first capacitor to form a first auxiliary circuit;
a second capacitor;
a six pole auxiliary winding displaced 90 elec-trical degrees from said main stator winding, when con-nected to form six poles, and connected in series with said second capacitor to form a second auxiliary circuit;
and means for alternatively connecting one of said first and second auxiliary circuits in parallel with said main stator winding.
14. A single phase alternating current electric motor comprising:
a main stator winding wound to pass through a plurality of uniformly spaced slots in a stator and including two identical coil groups each having three series connected coils wherein all six coils are approximately equally spaced around the motor periphery, corresponding coils in each of said coil groups are spaced 180 mechanical degrees apart, and a first coil in each of said coil groups has a number of turns which differs from the number of turns of the other coils;
means for connecting said two coil groups in series for six pole motor operation; and means for connecting said two coil groups in parallel for four pole motor operation, wherein one of said coil groups has a reversed polarity with respect to its connection for six pole operation.
a main stator winding wound to pass through a plurality of uniformly spaced slots in a stator and including two identical coil groups each having three series connected coils wherein all six coils are approximately equally spaced around the motor periphery, corresponding coils in each of said coil groups are spaced 180 mechanical degrees apart, and a first coil in each of said coil groups has a number of turns which differs from the number of turns of the other coils;
means for connecting said two coil groups in series for six pole motor operation; and means for connecting said two coil groups in parallel for four pole motor operation, wherein one of said coil groups has a reversed polarity with respect to its connection for six pole operation.
15. An electric motor as recited in claim 14, wherein each coil group of said main stator winding com-prises:
a primary coil; and two secondary coils, wherein said primary coil has more turns and a larger span than said secondary coils.
a primary coil; and two secondary coils, wherein said primary coil has more turns and a larger span than said secondary coils.
16. An electric motor as recited in claim 15, wherein the span of each of said primary coils is about two pole pitches and the span of each of said secondary coils is about one pole pitch.
17. An electric motor as recited in claim 15, wherein said primary coils are centered between said secondary coils of the same coil group.
18. An electric motor as recited in claim 15, wherein the number of turns in each of said primary coils is approximatly 1-2/3 times the number of turns in each of said secondary coils.
19. An electric motor as recited in claim 14, further comprising:
an auxiliary stator winding wound to pass through said uniformly spaced slots in said stator and including two identical coil groups each having three series connected coils with corresponding coils in each of said auxiliary winding coil groups being spaced 180 mechanical degrees apart and wherein all six auxiliary coils are equally spaced around the motor periphery and displaced 90 electrical degrees from said main stator winding coils at least two of said six auxiliary coils having an equal number of turns which differs from the number of turns in the other auxiliary coils;
a capacitor;
means for connecting said two auxiliary coil groups in series with each other and in series with said capacitor for six pole motor operation.
an auxiliary stator winding wound to pass through said uniformly spaced slots in said stator and including two identical coil groups each having three series connected coils with corresponding coils in each of said auxiliary winding coil groups being spaced 180 mechanical degrees apart and wherein all six auxiliary coils are equally spaced around the motor periphery and displaced 90 electrical degrees from said main stator winding coils at least two of said six auxiliary coils having an equal number of turns which differs from the number of turns in the other auxiliary coils;
a capacitor;
means for connecting said two auxiliary coil groups in series with each other and in series with said capacitor for six pole motor operation.
20. An electric motor as recited in claim 19, wherein each coil group of said auxiliary stator winding comprises:
a primary auxiliary coil; and two secondary auxiliary coils, wherein said primary auxiliary coil has more turns and a larger span than said secondary auxiliary coils.
a primary auxiliary coil; and two secondary auxiliary coils, wherein said primary auxiliary coil has more turns and a larger span than said secondary auxiliary coils.
21. An electric motor as recited in claim 20, wherein the span of each of said primary auxiliary coils is about two pole pitches and the span of each of said secondary auxiliary coils is about one pole pitch.
22. An electric motor as recited in claim 20, wherein said primary auxiliary coils are centered between said secondary auxiliary coils of the same coil group.
23. An electric motor as recited in claim 20, wherein the number of turns in each of said primary auxil-iary coils is approximately 1-2/3 times the number of turns in each of said secondary auxiliary coils.
24. An electric motor as recited in claim 19, further comprising:
means for connecting said two auxiliary coil groups in parallel with each other and in series with said capacitor for four pole operation, wherein one of said auxiliary coil groups has a reversed polarity with respect to its connection for six pole operation.
means for connecting said two auxiliary coil groups in parallel with each other and in series with said capacitor for four pole operation, wherein one of said auxiliary coil groups has a reversed polarity with respect to its connection for six pole operation.
25. An electric motor as recited in claim 19, further comprising:
a second capacitor; and means for connecting said two auxiliary coil groups in parallel with each other and in series with said second capacitor for four pole operation, wherein one of said auxiliary coil groups has a reversed polarity with respect to its connection for six pole operation.
a second capacitor; and means for connecting said two auxiliary coil groups in parallel with each other and in series with said second capacitor for four pole operation, wherein one of said auxiliary coil groups has a reversed polarity with respect to its connection for six pole operation.
26. An electric motor as recited in claim 14, further comprising:
a first capacitor;
a four pole auxiliary winding displaced 90 electrical degrees from said main stator winding in the four pole configuration and connected in series with said first capacitor to form a first auxiliary circuit;
a second capacitor;
a six pole auxiliary winding displaced 90 elec-trical degrees from said main stator winding in the six pole configuration and connected in series with said second capacitor to form a second auxiliary circuit; and means for alternatively connecting one of said first and second auxiliary circuits in parallel with said main stator winding.
a first capacitor;
a four pole auxiliary winding displaced 90 electrical degrees from said main stator winding in the four pole configuration and connected in series with said first capacitor to form a first auxiliary circuit;
a second capacitor;
a six pole auxiliary winding displaced 90 elec-trical degrees from said main stator winding in the six pole configuration and connected in series with said second capacitor to form a second auxiliary circuit; and means for alternatively connecting one of said first and second auxiliary circuits in parallel with said main stator winding.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US484,020 | 1983-04-11 | ||
| US06/484,020 US4476422A (en) | 1983-04-11 | 1983-04-11 | Single phase four pole/six pole motor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1201749A true CA1201749A (en) | 1986-03-11 |
Family
ID=23922406
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000441557A Expired CA1201749A (en) | 1983-04-11 | 1983-11-21 | Single phase four pole/six pole motor |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US4476422A (en) |
| JP (1) | JPS59191459A (en) |
| KR (1) | KR850003074A (en) |
| CA (1) | CA1201749A (en) |
Families Citing this family (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2283133B (en) * | 1993-10-20 | 1998-04-15 | Gen Electric | Dynamoelectric machine and method for manufacturing same |
| US5635565A (en) * | 1995-01-13 | 1997-06-03 | Japan Synthetic Rubber Co., Ltd. | Polymerized aromatic vinyl and vinyl cyanide onto rubber |
| US5825113A (en) * | 1995-07-05 | 1998-10-20 | Electric Power Research Institute, Inc. | Doubly salient permanent magnet machine with field weakening (or boosting) capability |
| US5733041A (en) | 1995-10-31 | 1998-03-31 | General Electric Company | Methods and apparatus for electrical connection inspection |
| US5758709A (en) * | 1995-12-04 | 1998-06-02 | General Electric Company | Method of fabricating a rotor for an electric motor |
| US6198238B1 (en) | 1995-12-07 | 2001-03-06 | Borealis Technical Limited | High phase order cycloconverting generator and drive means |
| US6570361B1 (en) | 1999-02-22 | 2003-05-27 | Borealis Technical Limited | Rotating induction apparatus |
| US5825111A (en) * | 1996-11-12 | 1998-10-20 | Emerson Electric Co. | Single-phase induction motor 4/6 pole common winding connection with magnetic motive force symmetrically distributed |
| US6255755B1 (en) * | 1998-06-04 | 2001-07-03 | Renyan W. Fei | Single phase three speed motor with shared windings |
| US6922037B2 (en) * | 1999-02-22 | 2005-07-26 | Borealis Technical Limited | Rotating induction apparatus |
| US6864661B2 (en) * | 1999-02-22 | 2005-03-08 | Borealis Technical Limited | Rotating induction apparatus |
| US6175209B1 (en) * | 1999-07-08 | 2001-01-16 | Emerson Electric Co. | 2/4-pole PSC motor with shared main winding and shared auxiliary winding |
| US6175208B1 (en) | 1999-10-01 | 2001-01-16 | Emerson Electric Co. | High efficiency permanent split capacitor motor for driving a compressor |
| US6271639B1 (en) * | 2000-02-08 | 2001-08-07 | Emerson Electric Co. | Capacitor start single phase induction motor with partial winding starting |
| US20070108863A1 (en) * | 2003-09-30 | 2007-05-17 | Hubert Bischof | Stator for an electrical machine |
| US8944783B2 (en) * | 2006-06-27 | 2015-02-03 | Schlumberger Technology Corporation | Electric progressive cavity pump |
| US7911175B2 (en) * | 2008-08-18 | 2011-03-22 | Emerson Electric Co. | Two speed induction motor with tapped auxiliary winding |
| EP2813819B1 (en) * | 2012-02-10 | 2017-08-09 | Daesung Electric Co., Ltd | Slotless resolver, method for manufacturing same, and wiring tool used therefor |
| US10731627B1 (en) | 2019-10-07 | 2020-08-04 | Timm A Vanderelli | Low wind generator with internal rechargeable power |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2464253A (en) * | 1946-09-16 | 1949-03-15 | Wayne J Morrill | Condenser induction motor circuit |
| GB966576A (en) * | 1961-08-31 | 1964-08-12 | Nat Res Dev | Improvements in or relating to rotary electric machines |
| GB1267924A (en) * | 1968-09-25 | 1972-03-22 | Nat Res Dev | Improvements in or relating to rotary electric machines |
| US3619748A (en) * | 1968-10-02 | 1971-11-09 | Nat Res Dev | Two-speed, single-phase electric motors |
| US4066937A (en) * | 1976-01-13 | 1978-01-03 | Lennox Industries, Inc. | Control circuit for a two speed single phase motor |
-
1983
- 1983-04-11 US US06/484,020 patent/US4476422A/en not_active Expired - Fee Related
- 1983-11-21 CA CA000441557A patent/CA1201749A/en not_active Expired
- 1983-12-09 JP JP58233468A patent/JPS59191459A/en active Pending
- 1983-12-09 KR KR1019830005833A patent/KR850003074A/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| KR850003074A (en) | 1985-05-28 |
| JPS59191459A (en) | 1984-10-30 |
| US4476422A (en) | 1984-10-09 |
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