US1896398A - Transformer connection - Google Patents

Description

Feb. 7, 1933.

F. W. GAY

Filed May 29, 1930 2 Sheets-Sheet 1 Law La\ Lab A4 34 1 34 FIG. I-

INVENTOR Feb.7, 1933. GAY 1,896,398

TRANSFORMER CONNECTION Filed May 29, 1930 2 Sheets-Sheet 2 IN VEN TOR fiazer 60 BY W 6 ATTORNEY\ My, 4

Patented Feb. 7, 1933 PATENT OFFICE FRAZER W. GAY, OF NEWARK, NEW JERSEY TRANSFORMER CONNECTION Application filed May 29,

My Patent No. 1,7 98,874 covers the switching of transformer windings from series to parallel connection and vice versa, whereby the flux density in the magnetic core is altered a and a preferred form is illustrated in which the number of windings connected in series is odd.

This invention relates to the changing of magnetic flux densities in a polyphase transformer bank by phase changing whereby the efliciency of the transformer may be held at a high value over a very wide load range and the maximum capacity of a given size of transformer to carry load may be made very great.

It is an object of this invention to alter the flux densities in the magnetic circuits of a polyphase transformer bank by phase changing whereby the capacity of the transformer bank to carry load is varied while at the same time maintaining load on the bank.

It is a further object of this invention to so arrange the magnetic circuits that when the transformer bank is operating with minimum 2 flux density in its core, two windings in the same phase will have a magnetic circuit in common, said circuit being arranged for mini mum length, while when the transformer bank is operating at high flux density said two windings will interlink magnetic fluxes of different time phase and the geometric sum of said fluxes will pass through a leakage path provided for that purpose.

It is a further object of this invention to provide a switching method requiring only one operation to change the windings from series to multiple or vice versa.

It is a further object of this invention to provide a series multiple connection which 0 only requires a switch closure to change from series to multiple whereby the transformer bank impedance can be almost instantly reduced to its minimum and the bank capacity at the same time increased to its maximum in case a very heavy load is suddenly applied. It is obvious that this switch closure may be made automatically and almost simultaneously with the rise in load. It is also obvious that the change to series connection by opening the switch may be made automatic and 1930. Serial NO. 457,074.

may not occur until the load has diminished to the desired low value generally between and of its rated value.

It is a further object of this invention to provide six windings per primary and six windings per secondary (and six windings per tertiary if required) in a three phase transformer bank and six magnetic circuits and the turn ratio of windings on one magnetic circuit the same as the turn ratio of windings on the other magnetic circuits, whereby the time phase of the flux in one magnetic circuit may be altered with respect to the time phase of the flux in the other magnetic circuits and the voltage on individual windings may be increased or decreased, while the windings in circuit on all magnetic circuits retain a constant number of turns.

In the preferred form of the invention it is proposed to connect the six circuits in primary, secondary (tertiary etc. if required) in series delta during light load periods, in parallel star during intermediate load periods and in parallel delta during very heavy load periods.

Other objects of this invention not at this time more particularly enumerated, will be clearly understood from the following detailed description of the same.

The invention is clearly illustrated in the accompanying drawings, in which Fig. 1 represents a cross section of a transformer of the present invention.

Fig. 2 is a diagrammatical representation of the transformer shown in Fig. 1 with connections to a 6 P. D. T. switch.

Fig. 3 is a schematic diagram showing the connections of the various windings shown in Fig. 2 when the switch is thrown down.

Fig. 4 is a schematic diagram showing the connections of the windings shown in Fig. 2 when the switch is thrown up, and

Figs. 5, 6 and 7 are wiring diagrams illustrating the manner of developing the diagram of Fig. 4.

Fig. 1 shows a shell type transformer designated as 31, having two coaxial cores 32 and 33 and connecting yokes 34, 35, 36, and 37. Leakage paths 38 and 39 are provided between the two coil groups shown. One coil group consists of a high tension coil Ha 1' sandwiched in between the two halves of the low tension winding La 1, La 1. V The other coil group consists of a high tension coil Ha 2 sandwiched in between the two halves of the low tension winding La 2, La 2. Fig. 2 shows the low tension windings of a bank of three transformers like Fig. 1 connected delta and the high tension windings connected delta. The high tension winding receives power from feeder wires 4, 5, 6 and the low tension windings transmit the power over wires 1, 2, 3 to a power bus, not shown.

A P. D. T. switch designated 7, has the hinge clips of poles 8, 9, and connected to the junction points of windings La 1, La 2 and L?) 1, L?) 2 and L0 1, L0 2 respectively and poles 11, 12, and 13 have the hinge clips connected to the junction points of high tension windings Ha 1, Ha 2 and HZ) 1, H?) 2" and H0 1,1-10 2 respectively. The upper jaw clip 8 of pole 8 is connected by wire 14 to lead 3. The upper jaw clip 9 of pole 9 is connected by wire 15 to lead 2. The upper jawclip 10 of pole 10 is connected by wire 16 to lead 1. The upper jaw clip 11 of pole 11 is connectedby wire 17 to lead 6. The upper jaw clip 12 of pole 12 is connected by wire 18 to. lead 5. The upper jaw clip 13 of pole 13 is connected'by wire 19 to lead 4. The lower jaw clips 11", 12 and 13" respectively of. poles 11, 12, and Bare connected together by wire 20 and the lower jaw clips 8", 9 and 10 respectively of polesS, 9, and 10 are connected together by wire 21. When 6 P. D. T. switch 7 is closed down so that the switch poles 8 to 13 inclusive engagethe lower jaw clips 8 to 13inclusive, the'junction points of the series connected low tension windings are connected together by wire 21 to form a two circuit star connec tion and the junction point of the series connected high tension windings are connected together by wire 20 to form a two circuit star connected high tension winding as shown in Fig. 3. 1

When 6 P. D. T. switch 7 is closed up so that the switch poles 8'to 13 inclusive engage the upper jaw clips 8 to 13, inclusive, the several windings become connected as illustrated in Fig. 5, and then the junction point of low tension windings La 1,La 2 is connected to lead 3 by wires 14 and 22 so that the windings- La 1 and La 2-are connected in open delta across phase leads 2, 3, 1. The corresponding hightension windings H0. 1, Ho 2 have the junction points connected to lead 6 by wires 17 and 23 so that these windings are connected in open delta across high tension phase leads 5, 6, 4. In the same manner it is evident that the junction point of windings L0 1, L0 2 is connected to phase lead 1 by'wires 16 and 24 and the junction point of windings L?) 1 and Lb 2 is connected by wire 15' and wire to form a standard two circuit delta connected transformer bank as shown in Fig. 4and Fig.7. 7 'It will be evident from a study-of Fig. 3 that when 6 P. D. T. switch 7 is closed down La land La 2 which were in phase in Fig. 2

with switch open have their phase changed with respect to eachother 60 electrical degrees, while Fig. 4 shows that when switch 7 is closed up La 1 and La 2 areswung with respect to each other through an angle of- 120 degrees. A referenceto Fig. 1 will show that when switch 7 Fig. 2 is thrown down the vector sum of fluxes passing through core legs 32 and 33 will pass through leakage paths 38'and 39.

, As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted 'as illustrative and not in a limiting sense.

What is claimed is 1 1. In a system of transformer connections, a three phase power transmission system having three primary phase conductors and three secondary phase conductors, v transformer means connected in said transmission system, said transformer means havingfa primary cir uit comprising a primary winding with six winding'sections, therebeing two of said winding sectionsconnected in series across the two primary-phase conductorsof each phase of said three phase system, a secondary circuit comprising a secondary winding with six winding sections, there being two of said winding sections connected inseries across the two secondary phase conductors of each phase of said three phase system, and switching means connected to said transformer means for switching each of said winding sections to a different phase position while maintaining said primary and secondary cir cuits intact, whereby the capacity of said transformer means to carry load is varied.

2. In a system of transformer connections, a three phase primary circuit having three phase conductors and a three phase secondary circuit having threephase conductors, transformer means connected in said circuits, said transformer means comprising a primary winding having three pairs of complementary winding sections, each pair of complementary winding sections being connected in series across the two conductors of a respective phase of said three phase primary circuit, and

a secondary winding having three pairs of complementary winding sections, each pair of complementary winding sections being connected in series across the two conductors of a respective phase of said three phase secondary circuit, and switching means connected to said circuits for switching each primary winding section and its inductively related secondary winding section to a different phase position with each winding section lying in a phase position which is dissimilar from the phase position of its respective com lementary winding section, whereby a di erent transformer operation is obtained.

3. In a system of transformer connections, a three phase transmission system having three primary phase conductors and three secondary phase conductors, three phase transformer means connected in said system, said transformer means comprf sing a primary winding having two winding sections per phase, said two winding sections of each phase bein connected in series across the two primary paase conductors of the respective phase, a secondary winding having two winding sections per phase, said two winding sections of each phase being connected in series across the two secondary phase conductors of the respective phase, and cores providing two magnetic circuits per phase, one of said primary winding sections and its inductively associated secondary winding section of each phase interlinking one of said magnetic circuits and the other of said primary winding sections and its inductively associated secondary winding section of each phase interlinking the other of said magnetic circuits, and switching means connected to said transformer means for switching each of the respective winding sections of the primary and secondary windings across a different phase of said circuit, said different phase having a phase conductor to which the respective winding section was previously connected.

4. In a system of transformer connections, a three phase primary circuit having three phase conductors and a three phase secondary circuit having three phase conductors, three phase transformer means connected in said circuits, said transformer means comprising a primary w nding having three pairs of complementary winding sections, each pair of complementary winding sections being solidly connected in series across the two conductors of a respective phase of said three phase primary winding circuit, and a secondary winding having three pairs of complemcntary winding sections, each pair of complementary winding sections being solidly connected in series across the two conductors of a respective phase of said three phase secondary circuit, and cores providing two magnetic circuits per phase, each respective primary winding section and its inductively associated secondary winding section interlinking a respective one of the two magnetic circuits of their respective phase, and means for changing the phase position of all of said primary and secondary winding sections so that twoprimary winding sections are respectively connected in multiple across each phase of said primary circuit, and two secondary winding sections are respectively connected in multiple across each phase of said secondary circuit, whereby the capacity of said transformer means is increased as for heavy loadperiods.

5. In a system of transformer connections, a three phase transmission system having three primary phase conductors and three secondary phase conductors, three phase transformer means connected in said system, said transformer means comprising a primary winding having two winding sections per phase, said two winding sections of each phase being connected in series across the two primary phase conductors of the respective phase, a secondary winding having two winding sections per phase, said two winding sections of each phase being connected in series across the two secondary phase conductors of the respective phase, and switch ing means connected to said transformer means and arranged, on being closed, to connect the two primary winding sections of each phase in open delta across the primary phase conductors of the other two phases, said switching means also serving to connect said secondary winding sections of each phase in open delta across the secondary phase conductors of the other two phases.

6. In a system of transformer connections, a three phase primary circuit having three phase conductors and a three phase secondary circuit having three phase conductors, transformer means connected in said circuits, said transformer means comprising a primary winding having three pairs of complementary winding sections, each pair of complementary Winding sections being connected in series across the two conductors of a respective phase of said three phase primary circuit, a secondary winding having three pairs of complementary winding sections, each pair of complementary winding sections being connected in series across the two conductors of a respective phase of said three phase secondary circuit, and means arranged to switch the complementary primary winding sections of each respective phase to different and adjacent phase positions, whereby each primary winding section will be connected in parallel with another primarywinding section, said means also 7 serving to switch the complementary secondary winding sections of each respective phase to difierent and adjacent phase positions, wherebyeach secondary winding section will be connected in parallel with another secondary winding section, said transformer means having a core providing two magnetic circuits per phase, each of said magnetic circuits per phase serving to interlink one primary winding section and one secondary winding section'in that phase for the parallel connection, said core providing a magnetic path consisting of portions of both of said magnetic circuits and interlinking all of the Winding sections in a phase for the series connection. V V

7. In a'system of transformer connections, a three phase transmission system having three primary phase conductors and three secondary phase conductors, three phase transformer means connected in said system, said transformer means comprising a primary winding having two winding sections per phase, said two winding sections of each phase being-rconnected in series across the two primary phase conductors of the respective phase, a secondary winding having two winding sections per phase, said two winding sections of each phase being connected in series across the two secondary phase conductors of the respective phase, and switching means connected to said transformer means and arranged, on being closed, to connect the junction pointof the two primary winding sections of each respective phase to the third primary phase conductor, said switching means also serving, upon closing, to connect the junction point of the two secondary winding sections of each respective phase to the third secondary phase conductor.

FRAZER w. GAY.

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