USRE13638E - Best available copx - Google Patents

Description

A BE'STAVAILABLE COP.

- K. A. PAULY.

- INDUCTION MOTOR.

Reissued Nov. 4, 1913.

APPLICATION I'IIQED 0013, 1913.

" Witnesses Inventor:

5M 4 2,94 Karl A. Paul 2 SHEETS-SHEET 2.

K. A. PAULY.

INDUCTION MOTOR.

APPLICATION PIL-nn 001m. 1913.-

BEST AVAILABLE COP.

Reissued Nov. 4, 1913.

TEST AVAILABLE COP: i

KARL A. IPAULY, 3F

sonnnncrenrgirnw some nssrenon. ro GENERAL ELECTRIC COMPANY, A oonronn'rrcn on new YORK.

INDUCTIONJYIQQZQR;

Specification of Reissucd Letters Patent.

teissned Nov. 4, 1913.

Original No. 1,087,270, dated July 15, 1913, Serial No. 61%,119. Application for reissue filed Qctobcr 3, 1913. Serial N10. 2433,2965.

To all whom it may concern:

-Be it known that I, KARL A. PAULY, e'

citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Induction- Motors, of which the following is a specification. 4 My invention relates to variable speed 'findnction' motors, and its object is to pro- ;vide s novel arrangement of rotor windings whereby the some rotor connections may be Used with ,e starting resistance for opera 'ffilOIl on both speeds. 15,, A two speed connection for the stator windings of induction motors is well known in the art, in which the relative direction of.

'current flow 1s reversed in half the coils of each phase to vary the number of poles in the ratio of two to one In such motors it has been customary heretofore either to employ a, squirrel cage winding, which of course adapts itself to any number of poles, or, if estnrting resistance is required for operation on both speeds, to provide a rotor with six collector rings. The reason for employing six collector rings is that with rotor windings as heretofore arranged in 'such motors, it is necessary to use a six Sic-phase rheostet, or to very theconnections of the rotor coils when changingfrom one speed to the other, since, if the rotor coils ere properly connected for one number of poles, they will be non-inductive to the stator winding for the other number of poles. g

By my invention 1 so arrange the rotor circuits that. without any change in their connections they ere in inductive relation to the stator Winding for both sets ofpoles. I accomplish this by forming sees phase-oi? the rotor winding in eiplurelity of groups of doils connected in a plurality of circuits, each: circuit comprising at plurality of groups displaced from each other so that their voltages are out of phase, the displacement being of such an emount'that the sum of the induced voltages of the coil groups is greater than zero for hoth niimbers of poles. I My invention will best he understood by reference to the'ecconipanying drawings, in whicl1 Figure 1 shows diagrammatically 2minduction motor nrrenged in accordance with my invention; Fig 9 and 3 are explanatorydisgrsms; and Fig. t shows a development of the windings of e'n'iotor like that shown inFigL- In the drawing, A A, B B", and C 6 represent the three phases of the stator winding 0%, indoctionmotcr, each phase consisting oftwo groups of coils, :1s A and A, from which connections ereled to the control switch D which is shown diegrsnp. metically with its contacts developed on e plane surface; This'switcliis arranged to vary the connections of the groups of coils so to reverse the-relative direction of current flowing in hell? the coils of each": '70 phase when the switchis thrown emcee position to the other. Thus, when the switch I) is moved to bring the left hand movable contacts in engagement with the stationary contact fingers, the source of current (indicated by the linewires E) is connectcd by means of the leads 7, 8 and 9 to the connections between'the groups C and B, B and A,,and A and C, the loads 10, 11 and 12 being; open,'tl1e winding being thus connected in delta, so that the current passes th roughthe two groups of each phase in series. When the "switch 3 is lthrown to bring the right hand movable contacts into engagement with the stationary contectfin: gers, the sourceof current is connected by mes the leads if, 11 and 12, to the junction. of" the two groups or each phase, the "5', it and 91mins; connected toget. er to a neutral point for the winding, The 'enrrent then in each phase flows from the junction point of the two groups through the twogroups in parallel to the neutral. Thus, the relative directions "5 AVAlLABLE COP".

of current in one half of each phase is reversed, and if the coils are properly connected in groups, the number of poles is thereby varied in the ratio of two to one, as is well understood in. the art. In the upper part of Fig. 4 is shown the development of a primary winding for a four pole-eight pole motor having three coils per phase per pole. The'rotor winding is alsoconnected three phase, and each phase consists of two groups of coils. One phase consists of the coil groups a and a; the second of Z) and b,- and the third of 0 and c. The displacement of these three phases is of the usual amount, and if-the motor be considered as operating with the smaller number of poles, the displacement is then 120 electrical de grces. VV-hen the motor is operating with the larger number of poles, this makes the relative displacement 240 electrical degrees.

The rotor winding is connected in three circuits, each comprising groups of coils from two ditlerent phases. Thus, for instance, one circuit comprises the coils o and 0; another 6 and a; and the third 0 and b. FUIEhCIDIOlG, the two groups of coils in each circuit are reversely connected. The result of this connection on the voltages of the three circuits is indicated diagrammatically in. Fig. 2, the coils a and 0 being connected in series and their induced voltages being 120 out of phase their voltages add to each other at an angle of 60, as shown. The same is true of each of the other circuits, so that the resultant volt-ages of the rotor circuits are nearly as great as though the coils of each phase were connected in series by themselves, in the usual manner.

The effect on the rotor voltages of varying the number of poles may be understood by comparing Fig. 3 with Fig. 2; Since with the smaller number of poles the voltages of coils a and Z) differ by 120, they will now differ 240 with the larger number of poles, as is indicated by comparing these two figures. Similarly, if the difiierence between ,the coils a and Q is 240 with the smaller number of poles, then with the larger number of poles they will dilier 480, or, hat is the same thing 120 Thus, comparing the lines, a, Z), c in Figs. 2 and 3, it will be seen that the lines representing coils Z) and 0 have simply changed places.

Coils 0 being still in phase with coils o and connected up as before, will have voltages induced in them in the same direction and will add their voltages to those of coils a.

at an angle of 120, as shown in Fig. 3. The net result, as shown by these two figures, is.

-- phase.

ing having its coils connected .in connections said groups for varying the ber of poles if desired. by reversing the con nections of the coils a, b and c,

Since the voltages in each circuit add to each other effectively for both numbers' of poles, the terminals of the circuits may be connected permanently to three collector rings, as indicated at F in Fig. 1, and to these collector rings, by means ofbrushes f, a starting resistance G may be connected, which may, therefore, be used with either number of poles. In the lower part of Fig. 4t is shown the development of a rotor wind ing having four coils per pole per phase, connected up as described above. I

The principle on which myinvention is based maybe worked out through many diflerent arrangements, and I do not desire to limit myself to the specific rotor connections which I have shown and described as one suitable embodiment of my invention, but I aim in the appended claims to cover all modifications which are within the scope of my invention. 7

What I claim as new and desire to secure by Letters Patent of the United States, is

1. In an induction motor, a stator winding having its coils connected in groups, connections for said groups for varying the relative connections of said groups to vary the number of poles in the stator winding,

and a polyphase rotor winding, each phase of which comprises a plurality of groups of coils connected in a plurality of circuits,

each of said circuits comprising a plurality of groups of coils in series displaced from each other so that their voltages are out of 2. In an induction motor, a stator Winding having the coils connected in groups, connections for said groups for varying the relative connections of said groups to vary the number of poles in the stator winding, and a polyphase rotor Winding, each phase of which comprises a plurality of groups of coils connected in a plurality of circuits, each of said circuits comprising a plurality of groups of coils in series displeased from each other so that their voltages are out of phase, collector rings to which the terminals of the rotor circuits are connected, and a starting resistance connected to said collector rings.

3. In an induction motor, a stator winda ing having its coils connected in group'gi connections for said groups for varying relative connections of said groups to vary' the number of poles in the stator winding, and a polyphase rotor winding, 'each'phase of which comprises a plurality of groups of coils, each group in each phase being con nected in a series circuit with-a group in a different phase.

l. In an induction motor,"a stator Wind I BEST AVAILABLE COP races relative connect-ions of said groups to vary the number of poles in the stator Winding and a polyphase rotor Winding, each phase of which comprises a plurality of groups of coils connected ina plurality of circuits, each group in each phase being connected in a series circuit with a group in a diilerent phase, collector rings to which the terminals of the rotor circuits are connected, and a 10 resistancewonnected to said collector rings In an induction motor, a stator winding having coils connected in groups, connections for said groups for varying the relative connections of said groups to vary the '15 number of poles in the stator winding, and

a polypha-se rotor Winding havinggroups of coils in each phase connected in a plurality of circuits, each of said circuits comprising groups of coils having different phase relations with difierent numbers of poles in the stator windin v 6. In an induction motor, a three phase stator winding, connections for changing the speed of said inotorby reversing the relative g5 direction of current flowing in one half of each phase of the stator, winding to vary the number of poles in the ratio of two to one, and a three phase rotor winding, the coils of the three phases being displaced from each other 120 electricaldegrees for the smaller'number of poles, and 940 electrical degrees for the larger number of poles, the coils being connected in three circuits,

each circuit comprising coils of two phases,

as the coils of one phase being reversely connected relative to the coils of the other phase in the same circuit.

an induction motor, a three phase stator'w inding, connections for changing the 40 speed ofsaid motor by reversing the relative direction. of current flowing in one half of each phase of the stator Winding to vary the number of poles in the ratio of two to one, and a three phase rotor winding, the coils of the three phases being displaced from each other 120 electrical degrees for the smaller number of poles, and E240 electrical degrees for the larger number of poles, the coils being connected in three circuits, each circuit comprising coilsof two phases,

the coils or one phase being rovers-sly connected relative to the coils of the other phase in the same circuit, collector rings to which the terminals of the rotor circuits are connected, and a starting resistance connected groups of coils in series displaced from each other so that their voltages are out of phase, the amount of such displacement being such that the voltages of the groups are more havin its coils connected in groups, connections Ior said groups for varying the relative connectlons of said groups to'vary the number of poles in the stator winding, a polyphase rotor Winding, each phase of which cornprises a plurality of groups of coils connect-- ed in a plurality of circuits, each of said circuits comprising plurality of groups of coils in series displaced from each other so that their voltages are out of phase, the amount of such displacement being such that the voltages of the groups are more. nearly in series than in opposition for one/connection of the primary winding, collector rings to which the terminals of the rotor circuits are connected, and a starting resistance connected to said collector rings.

10. In an induction motor, a polyphase stator Winding, connections for changing the speed of said motor by reversing. the relative direction of current flowing in one half of each phase of the stator winding to vary the number of poles in the ratio of two to one, and a 'polyphase rotor winding having its COllS connected in a plurality of circuits,

each circuit comprising coils of two phases.

11. In an induction motor, a polyphase stator winding, connections for changing the speed of said motor by reversing the relative direction of current flowing-in one half of each phase of the stator winding to vary the number of poles in the ratio of two to one, a polyphase rotor winding havmg its coils connected in a plurality of circuits, each' circuit comprising coils of two phases, col

lector rings to which the terminals of the the n mber of poles in the ratio of two to' one, and a rotor Winding having its coils connected in a plurality of circuits, each circuit comprising coils of two-phases, the coils of one phase being r'eversely connected relative to the coils of the other" phase in the same circuit,

13. In an induction motor, a polyphase stator winding, connections for changing the speed of said motor by reversing therelative 'tlirection current flowing in one half of each phase of the stator winding to vary the number poles in the'ratio oi twoto one, arotor winding having its coils connected in a plurality of circuits, each BEST AVAILABLE COP coils of one phase being reversely connected my band this 30th day of March, 1911.

relative to the coils of the other phase in l the same circuit, collector rings to which the AARL PAULY' 5 terminals of the rotor circuits are connecteol lVitncsses:

and a starting resistance connected to said BENJAMIN B. HULL, coliector ring HELEN ORFORD.

circuit comprising coils of two phases, the In Witness whereofil have hereunto

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