US3273053A

US3273053A - Multiple connected transformer

Info

Publication number: US3273053A
Authority: US
Inventors: Jack W T Allen; Ralph E Anderson
Original assignee: Individual
Current assignee: Individual
Priority date: 1963-03-29
Filing date: 1963-03-29
Publication date: 1966-09-13
Anticipated expiration: 1983-09-13

Description

p 1966 J. w. T. ALLEN ETAL 3,273,053

MULTIPLE CONNECTED TRANSFORMER Filed March 29, 1965 5 Sheets-Sheet 1 IO N '2400 COILS 20 V. COILS INVENTOR5 JACK WI ALLEN RALPH E.ANDERSON Aflorn cys Sept. 13, 1966 J. w. T. ALLEN ETAL 3,273,053

MULTIPLE CONNECTED TRANSFORMER 5 Sheets-Sheet 2 Filed March 29. 1963 INVENTORS. JACK W. T. ALLEN By RALPH E. ANDERSON A fforn eys Sept. 13, 1966 .1. w. "r. ALLEN ETAL 3,273,053

MULTIPLE CONNECTED TRANSFORMER Filed March 29, 1963 5 Sheets-Sheet 3 INVENTORS JACK W.T. ALLEN BY RALPH E. ANDERSON flrnlros f b i er-ks Afforne 1:

United States Patent 3,273,053 MULTIPLE CONNECTED TRANSFORMER Jack W. T. Allen, 312 N. 41st St., Fort Smith, Ark., and Ralph E. Anderson, 905 W. Vandervoort Ave., De Queen, Ark.

Filed Mar. 29, 1963, Ser. No. 269,010 14 Claims. (Cl. 323-48) This invention relates to electric transformers, their interconnections, and particularly to a mobile transformer substation for temporarily taking the place of both single and three-phase electric power distribution transformers of any of several common voltage ratings.

In power distribution systems, the power is distributed to the consuming circuits through suitable transformers which are adapted to reduce the voltage to appropriate levels. At times it becomes necessary to repair or replace such transformers, and it is desirable that the system supplied by the transformers remains energized while repairs or replacements are being made. Generally, mobile transformers, substituting for system transformers, correspond in phase and voltage rating only to those of the distribution system on which they are to substitute. Some mobile substations have been provided with dual or two input voltage ratings, selected by a selector switch, providing for use on either of the two voltage systems for which the substation was designed. However, these mobile transformers have been uniformly of either single-phase or three-phase characteristics, but not both. The transformers of the prior art have a special oil-filled housing generally corresponding to the usual distribution transformer, and are generally separately mounted on a suitable trailer or the like.

The present invention relates to a multi-rated, multipurpose transformer combination which is suitable for connection to either single or three-phase electric power lines for providing utilization or distribution voltages and which may be selectively adapted for application to various systems having different voltage and phase characteristics. The present invent-ion also relates to incorporating of the novel multi-rated, multi-purpose transformer combination as a part of an integrated transformer-trailer combination.

The present invention is particularly directed to a selfcontained mobile substation having a plurality of individual transformer unit-s mounted as an integral part of a trailer which constitutes the transformer housing as well as compartments for various accessories necessary for interconnecting of the transformer units to each other and to the power lines. In accordance with the present invention, a plurality of individual transformer units is provided each having a plurality of input windings and a plurality of output windings. Switch means are provided for interconnecting the windings on the input and the output side for a plurality of different voltages at either singlephase or three-phase current in accordance with selected voltage and phase systems employed in the currently available distribution systems.

In accordance with the present invention, each of the transformers is generally a single-phase core and coil assembly having three input or high voltage windings formed by a plurality of windings or single tapped winding. A pair of output or low voltage windings is magnetically coupled through the core to the high voltage windings. A first input switch selectively interconnects the three high voltage windings in series or parallel for higher or lower primary voltage inputs, respectively, and a second input switch selectively interconnects the windings of the several transformers either in a Y or delta connection for a three phase input or in series or parallel for a single phase input. The secondary windings are interconnected through a phase switch for either a single-phase or threephase output.

In accordance with another aspect of the present invention, a common enclosure or housing is mounted as and forms an integral part of a trailer assembly. The enclosure is internally divided to form an integral transformer chamber within which the individual core and coil assemblies and high voltage switches are disposed and immersed within a suitable insulating liquid such as oil. On opposite sides of this transformer chamber, suitable phase and voltage terminals are provided and interconnected through suitable switch means to allow the necessary phase and voltage interconnections. The top is provided with a suitable door means which can be opened and carry a suitable signal lamp to indicate the operation of the device. Within the top portions the necessary cables and accessories can be provided for interconnecting of the devices of the mobile transformer into the circuit.

The present invention thus provides a new and novel movile substation employing interconnected single-phase units providing either single or three-phase outputs and a multiple of input and output voltages as required in the various power distribution systems.

The drawings furnished herewith illustrate the best mode presently contemplated for carrying out the invention.

In the drawings:

FIG. 1 is a schematic circuit diagram of a two transformer unit adapted to be incorporated in a mobile substation trailer unit shown in FIGS. 2-5;

FIG. 2 is a side elevational view of a mobile substation trailer constructed in accordance with an aspect of the present invention;

FIG. 3 is a front elevational view for the mobile substation transformer trailer unit shown in FIG. 2 with a transformer connection such as shown in FIG. 1;

FIG. 4 is a view similar to FIG. 3 showing the back side of the trailer shown in FIG. 2; and

FIG. 5 is a top view with the top doors open and with parts broken away to show certain internal details of construction.

Referring to the drawings and particularly to FIG 1, a pair of

single phase transformers

1 and 2 of a basically similar construction is illustrated. Each of the

transformers

1 and 2 includes a primary having three individual primary coils or windings 3, 4 and 5, and 6, 7 and 8, respectively, selectively interconnected to connecting or input power leads 9, 10 and 11 for connection to incoming high voltage power lines of a high voltage system. A voltage switch 12 interconnects the three individual primary coils or windings 35, inclusive, and68, inclusive, for either of two input voltages and a phase switch 13 interconnects the

transformers

1 and 2 for either a single phase or three phase input. Transformer 1 includes a secondary having a pair of

secondary coils

14 and 15 magnetically coupled to the coils 3, 4 and 5 and similarly transformer 2 includes a secondary having a pair of secondary coils 16 and 17 magnetically coupled to the primary coils 6, 7 and 8 thereof. The secondary coils are adapted to be interconnected to four output leads or

lines

18, 19, 20 and 21 and provide utilization voltages as hereinafter described. A phase switch 22 connects the secondary coils 14 through 17, inclusive, to the output leads 18 through 21, inclusive, and a disconnect switch 23 is interposed between the phase switch 22 and the leads for selective completion of the output circuit.

The

transformers

1 and 2 are similarly constructed as conventional single phase units wherein each of the primary coils 3-8, inclusive, is adapted to have a minimum base voltage of 2400' volts impressed thereon in accordance with the conventional power distribution transmission systems in the United States. The present invention is particularly shown in connection with a winding ar- Patented Sept. 13, 1966 3 rangement for input voltages of 2400, 4160Y, 7200 and -12470Y volts and a single or three phase output voltages of 120 or 240 volts. (Coil ratios can be provided for other primary voltages.)

In FIG. 1, the coils 3-8 are shown as individual windings with the ends connected to the corresponding portion of switch 12. The coils may be formed as a single winding with openings or breaks in the Winding or provided with appropriate taps, not shown.

The voltage switch 12 includes a first switch deck 24 interconnected with the primary coils 3-5 of transformer .1 and a second switch deck 25 interconnected with the primary coils 6-8 of transformer 2. Each of the

switch decks

24 and 25 is similarly constructed and switch deck 24 is particularly referred to in connection with the description of the various components thereof. The switch decks are interconnected as shown by the gang line in accordance with usual construction and no other specific description or showing thereof is considered desirable or necessary.

Referring particularly to the switch deck 24, fixed

contacts

26, 27, 28, 29, 30 and 31 are shown circumferentially distributed on a circle with the

contacts

26, 27 and 28 grouped to the left side thereof and the

contacts

29, 30 and 31 grouped to the right or opposite side thereof. The contacts are shown distributed with approximately substantially 45 spacing between each of the contacts within each group of contacts and with approximately 90 between the two groups. A pair of

switch blades

32 and 33 of slightly greater arcuate length than 90 is interconnected for common simultaneous angular positioning with respect to the contacts 26-31, inclusive. In the illustrated embodiment of the invention, the switch blades 32 and 33'are either positioned in a horizontal (side by side) position engaging respectively the contacts 26-28, inclusive, and 29-31, inclusive, or in a vertical (one above the other) position wherein the switch blade 32 engages only contacts 28 and. 29 and the switch blade 33 engages only contacts 26 and 31.

. With the

blades

32 and 33 in the horizontal position, the windings 3-5 are interconnected for an input of either 2400 volts or 4160Y volts. In the vertical positioning of the

switch blades

32 and 33, the windings 3-5 are interconnected to form an input voltage of 7200 or 12470Y volts, as hereinafter more fully described.

. The three transformer coils 3, 4 and are interconnected to the contacts 26-31 as follows. Coil 3 has the one end interconnected to contact 27 and the opposite end connected to contact 31. Coil 4 has the left end connected to the contact 26 and the right end connected to the contact 29. Coil 5 has the left end connected to the contact 28 and the right end connected to the contact 30.

v The left end of winding 3 and therefore contact 27 is connected also directly to a primary connecting terminal 34 and the right end of the coil 5 is similarly connected to a second primary terminal 35 of the transformer 1. The incoming voltage is connected to the

terminals

34 and 35 with the windings 3, 4 and 5 interconnected through switch 12, respectively, in series or parallel depending upon the incoming voltage 1evel.

The transformer 2 is similarly interconnected by the switch deck 25 with corresponding elements similarly primed numbered therein for purposes of clarity and simplicity of explanation and to pair of

input terminals

36 and 37 corresponding respectively to

terminals

34 and 35. The incoming power lines 9, and 11 are selectively interconnected to the terminals 34-37, inclusive, by the phase switch 13. In the illustrated embodiment of the invention, the phase switch is adapted to connect together the windings of the

respective transformers

1 and 2 in either a parallel, an open delta or an open Y circuit.

The illustrated phase switch includes three

decks

38, 39 and 40 each of which is similarly constructed. The deck 38 will be described specifically with corresponding primed and double primed numerals applied to switch 39 and 40 each of which is nimilarly constructed. The simplicity of explanation.

Switch deck 38 includes a rotatable switch arm or blade 41 selectively engageable with any one of three circumferentially distributed contacts apart which are numbered 42-44, inclusive. Switch blade 41 is connected to a terminal 45 and establishes the primary circuit for a delta operation, a Y operation or a parallel operation when placed in engagement with

contacts

42, 43 and 44, respectively.

In the position shown in FIG. 1 with blade 41 engaging contact 44, the

decks

38, 39 and 40

interconnect transformers

1 and 2 in parallel, as follows. The input terminal 34 of transformer 1 is connected to power lead 9 and by lead 46 to contact 44 of deck 38. The terminal 35 is connected to terminal 45 of deck 40 and by blade 41" thereof to the contact 44". Lead 47 connects contact 44" to power lead 11.

Transformer 2 has the input terminal 36 connected to terminal 45 of deck 38 and by associated blade 41 to contact 44 which is connected by lead 46 to incoming power lead 9. Thus,

terminals

34 and 36 are both connected to the incoming power lead 9. Terminal 37 of transformer 2 is connected to incoming power lead 11.

Terminals

35 and 37 are thus similarly connected to the power lead 11. Each of the

transformers

1 and 2 has corresponding input terminals connected directly across leads 9 and 11 and are thus provided for parallel input on a single phase voltage connection. 7 If the incoming voltage is 2400 volts, the switch 12 is positioned to align the

contact blades

32 and 33 in the horizontal position in accordance with the 2400-volt setting and separately interconnect the coils 3, 4 and 5 of transformer 1 in parallel and the coils 6, 7 and 8 of transformer 2 in parallel.

For a 7200-volt connection, the switch 12 is actuated to position the

switch blades

32 and 33 in vertical position in FIG. 1 to interconnect coils 3, 4 and 5 of transformer 1 in series and coils 6, 7 and 8 of transformer 2 in series.

To accept a three phase open Y input, the

transformers

1 and 2 are connected in the open Y by similar positioning of

switch decks

38, 39 and 40 with blades 45 engaging the associated contact 43.

When blades 41 of switch 13 are moved to engage the corresponding contacts 43, the

transformers

1 and 2 are connected to incoming power leads 9, 10 and 11 in an open Y circuit. In this position,

terminals

34 and 37 remain directly connected to power leads 9 and 11 respectively. Terminal 35 of transformer 1, however, is now connected though blade 41" of deck 40 to contact 43 of deck 40 and through a lead 48 to contact 44" which is conected to power lead 11. Terminal 45" of deck 40 is connected to terminal 45' of deck 39 through a lead 49, which terminal is connected through blade 41' to contact 43' and thence to ground 50. Thus,

terminals

35 and 37 are both connected to power lead 11 and also to ground.

In the open Y connection, the terminal 36 of transformer 2 is connected to terminal 45 of deck 38, and through blade 41 to contact 43, thence through leads 51 and 52 to power lead 10. In summary, the open Y connection includes the terminal 34 of transformer 1 which is connected to power lead 9, and the corresponding input terminal 36 of transformer 2 is connected to power lead 10.

Terminals

35 and 37 are similarly interconnected to ground 50 and power lead 11 (lead 11 is connected to the grounded neutral of the power system) to complete the open W connection of the primary windings.

In the open W setting of the phase switch 13, the voltage switch 12 is properly positioned in the 2400-volt position for a power distribution system of 2400/4160Y volts and in the 7200-volt position for a system of 7200/ 12470Y volts.

The open delta position, established by positioning of blades 45 engaging contacts 42 of the phase switch 13 is employed for a 2400-volt power distribution system and the circuit is traced as follows.

Terminal 34 of transformer 1 remains directly connected to incoming power lead 9. Terminal 35 is connected to terminal 45" of deck 40, and through blade 41" to contact 42", thence through lead 51 to contact 43. A jumper lead 53 connects contact 43 to contact 42, which is connected through blade 41 to terminal 45, thence to terminal 36 of transformer 2. Thus, terminal 35 of transformer 1 and terminal 36 f transformer 2 are connected together. Since lead 51 is connected to power lead 10,

terminals

35 and 36 are also connected to incoming power lead 10. Terminal 37 of transformer 2 remains directly connected to incoming power lead 11. The open delta connection, in summary, includes lead 9 connected to terminal 34 of transformer 1, lead 10 connected in common to the

terminals

35 and 36 of

transformers

1 and 2, respectively, and lead 11 connected to terminal 37 of transformer 2.

In summary, the six primary windings 3-8, inclusive, of

transformers

1 and 2 are adapted to be connected to accept the five following inputs: A 7200-volt single phase input wherein the windings within each transformer are connected in series and in parallel with each other across power lines 9 and 11; a 2400-volt single phase input wherein the windings within each of the

transformers

1 and 2 is connected in parallel and the primaries of

transformers

1 and 2 the windings thus connected to power lines 9 and 11 in parallel. The open Y connection has the individual windings 3-8 within each of the

transformers

1 and 2 connected in series or in parallel by proper setting of switch 12 and with the power line 9 connected to terminal 3 4, line 11 connected to

terminals

37, 35 and common ground. The primary line 11 constitutes a common neutral. The power lines 9-10 may then be connected to either a three phase system voltage of 2400/ 4100 Y input or 7200/ 12470 Y input. The fifth primary input connection is the open delta for three phase 2400- volt power distribution system. The voltage switch 12 is set to the 2400-vo'lt position to connect windings 3, 4 and 5 in parallel and windings 6, 7 and 8 in parallel. The phase switch 13 is connected to the delta position. Line 9 is connected to terminal 34 of transformer 1 and line 11 is connected to terminal 37 of transformer 2 and line is connected to

terminals

35 and 36 through deck 39 of switch 13.

For each of the above five inputs, the

secondary windings

14 and 15 of transformer 1 and windings 16 and 17 of transformer 2, as illustrated, are adapted to be interconnected for either single phase or three phase output at a distribution voltage of 120 or 240 volts.

The

secondary windings

14 and 15 of the transformer 1 are provided with a common terminal 54 connecting winding ends 55 and 56. Similarily, the secondary windings 16 and 17 of transformer 2 include a common terminal 57 which is connected directly to a ground 58 and winding ends 59 and 60.

Terminals

54 and 57, the opposite end terminals 61 and 62 of

windings

14 and 15, and the

opposite end terminals

63 and 64 of windings 16 and 17 are interconnected by the switch 22 for connecting the secondary windings 14-17 for either a single phase output or a three phase open delta output, as hereinafter described.

Disconnect switch 23 connects the power :lines 19-21 to the

transformers

1 and 2. Switch 23 is a three-pole single-throw unit having the respective contact arms 65, 66 and 67 interconnected to the output windings of

transformers

1 and 2, as hereinafter described. The contact arms 65, 66 and 67 simultaneously engage associated contacts 68, 69 and 70 respectively which are connected to corresponding output three

phase lines

19, and 21. Line 18 constitutes a common neutral.

The output presented at lines 18-21 is either a threewire single phase or a three-wire three phase voltage 6 with a lighting tap or a four-wire three phase voltage depending upon proper positioning of switch 22.

The phase switch 22 is a three-pole, double-throw switch and includes the three ganged contact arms 71, 72 and 73 which selectively engage corresponding

threephase contacts

74, 75 and 76 or single phase contacts 77, 78 and 79.

The three phase connection is established by engaging switch arms 71-73 of switch 22 with the three

phase contacts

74, 76 and is described as follows.

A lead 80 interconnects the contact arm 71 to the terminal 61 of transformer 1. Contact arm 72 is connected to the common terminal 54 of transformer 1 by a lead 81 and contact arm 73 is connected to the third terminal 62 of transformer 1 by a lead 82. The three phase contact 74 which is associated with arm 71 is connected by a lead 83 to the switch arm 67 of switch 23 and thereby to line 21. A lead 84 interconnects contact 76 of switch 22, terminal 63 of transformer 2 to each other and is connected to the switch arms 65 of

switch

23, and 77 of switch 22. A lead 85 interconnects the terminal 64 of transformer 2 directly to the contact arm 66. The output windings are therefore connected in an open delta circuit with terminal 61 connected to line 21,

terminals

62 and 63 connected to line 19, .and terminal 64 connected to line 20.

The single phase output connection is established by moving the switch arms 7.1-73 of switch 22 into engagement with the single phase contacts 77-79 and is traced in the illustrated embodiment of the invention as follows. A lead 86 connects the contact 77, which is connected to terminal 61 of transformer 1 by switch arm 71 and lead 80, to the switch arm 65 of disconnect switch 23 and thus to line 19. The corresponding terminal 63 of transformer 2 is also connected to switch arm 65 by the lead 84. A lead 87 connects the contact 78 of the phase switch 22 to the ground 58 and thus to the neutral line 18. A lead 88 interconnects the contact 79 of the three phase switch 22 to the switch arm 66 of switch 23 in common with the terminal 64 of the transformer 2 which is connected there-to by lead 85. The

transformers

1 and 2 each have their respective secondary windings connected in parallel and connected between

lines

19 and 20 and ground 18. A single phase 240 volts exist between

lines

19 and 20 and a volts appear between line 18 and each of the

lines

19 and 20.

The embodiment of the invention illustrated in FIG. 1 thus provides a pair of

transformers

1 and 2 each having a single phase core and coil assembly interconnected through the phase selection switch 13 to the incoming power lines 9-11, inclusive, for either a single phase or a three phase input. The voltage selecting switch 12 connects the individual windings 3-8 in series or parallel in accordance with the incoming primary voltage. The secondary phase switch 22 connects the secondary windings 14-17 for either single phase or three phase output. The secondary switch 22 directly establishes connection and eliminates any necessity for manual rearranging and connecting of the connecting cable in accordance with usual practice. At all times a ground neutral is maintained available at line 18 in the illustrated embodiment of the invention.

In accordance with the preferred construction of the present invention, the transformer circuit and assembly :as shown in FIG. 1 is formed as an integral part of a trailer assembly as shown in FIGS. 2-5, inclusive. In FIGS. 2-5, the corresponding elements of FIGS. 1 and 2 are similarly numbered.

Referring particularly to FIG. 2, a mobile transformer trailer includes a superstructure or frame 89 which is supported by suitable wheels 90. A tow bar 91 is secured to the frame 89 for attachment to a suitable vehicle, not shown. A housing 92 is secured to the frame structure 89 and is formed of relatively continuous walls to form a box-like enclosure within which

transformers

1 and 2 are housed as subsequently described. a Housing 92 is provided with rear doors 93, front doors 94, and four top doors 95.

A rotary beacon 96 is secured to the underside of one :of the top door-s 95 and located with-in the housing 92 with the doors closed. When doors 95 are opened, the beacon light 96 projects upwardly to provide a clearly visible warning light.

A transformer compartment 9'7 is provided within I ousing 92. The transformer compartment 97 is an in- ;tegralpart-cf the trailer housing 9-2 and the primary windings 3-8, inclusive, and the secondary windings 14- 17, inclusive, and the associated cores 98 and 99, respectively, of the

transformers

1 and 2 are suitably mounted therein. The compartment 97 is filled with a suitable oil 100 for insulating and cooling of the transformer windings and cores.

- The connections of the trans-

formers

1 and 2 extend through the front and top walls of the transformer compartment 97 with the secondary windings connected to a double throw switch unit 101 housing switch 22 and a single-throw switch unit 102 housing switch 23.

Switch units

101 and 102 are mounted on the exterior of the front wall of compartment 97 and behind the doors 94. The phase switch unit 101 includes an outer operating arm 103 coupled directly to the three switch arms 71, 72 and 73 of FIG.- 1. The disconnect switch unit 102 includes an external operating arm :104 similarly coupled to the switch arms 65, 66 and 67 of the switch 23 in FIG. 1. Six secondary terminal bushings 105 are mounted in the front wall of compartment 97 corresponding to

terminals

54, 57, .61, 62, 63 and 64, in FIG. 1. The bushings 105 are properly interconnected withinthe interior of the compartment and the lines 18-21, inclusive, extend upwardly into a cable protective compartment 106 in the top-portion of the housing 92, as most clearly shown in FIG. 5. The lines 1 821, inclusive, are coiled within the cable compartment for storage. The top doors 95, when closed, protect the-lines from the elements.

j Three primary bushings 107 are mounted on the top wall of the transformer compartment 97 and interconnected. into the circuit through protective fuses 108 mounted on the back wall of the compartment. The prirnary power lines 9, and 11 also extend upwardly from the interior of compartment 97 and are coiled within the cable compartment 106.

The top doors 95 provide the protective cover for the line storage compartment 106 when closed and extend substantiallyupwardly when open making the roof inaccessible after the lines have been withdrawn for circuit connection.

v The beacon light 96 attached to one of the hinged doors 95 provides a plainly visible warning light when the substation is inv use. .A suitable switch 109, shown in FIG. 3, is conveniently mounted on the front wall of compart- I nent 97 for controlling the light 96.

A control knob 1:10 is mounted behind rear doors 93 and is coupled to blades 41 of phase switch 13 to simultaneously and similarly position the contact blades 45 of the

switch decks

38, 39 and 40 of FIG. 1. A similar control knob 111 is provided and coupled to simultaneously position the

switch blades

32 and 36 of

decks

24 and 25 of the voltage switch 12.

Also, illustrated in FIGS. 2-5 are footed jacks 112 used for leveling and steadying the trailer. Jacks 112 may be cranked into the trailer housing with cranks, not shown, engaging the jack operating mechanism through holes 116. Cranks are stored in housing 92 when not 1n use.

Permanently fixed to drawbar 91 is hitch plate 115 with holes suitably spaced to permit attachment of pintle ring 113 or ball socket 114 at whatever height may be necessary to accommodate the towing vehicle.

7 The present invention provides a versatile substation having integrated single phase transformers having voltage and phase switch means selectively interconnecting for either single phase or three phase input and output connections.

Although the invention has been specifically illustrated in connection with a pair of unitized single phase core and coil assemblies, the present invention can readily be expanded to employ three unitized single phase core and coil assemblies generally of the construction of that previously described. Voltage and phase selection switches for the primary windings would again provide the single phase and three phase Y or delta connections and for the secondary windings would provide the single or three phase outputs. The voltage switch on the primary side would include an additional switch deck for the added transformer and the phase switch would have three decks with additional contacts to properly interconnect the third transformer. With three transformers, complete Y and delta connection-s would be provided rather than the open Y and open delta heretofore described. The various additional contacts required on the phase switch and the interconnection thereof as well as the interconnection of the secondary windings of the third transformer will be obvious to those skilled in the art in view of the embodiment given above and no further description thereof is given.

As previously noted, the multiple primaries and secondaries may be formed of a tapped winding assembly or separate and distinct coils and are similarly defined in the claims as a plurality of windings.

The three phase secondary connection has been described and illustrated particularly as a delta circuit. Any other suitable connection may readily be provided such as the common/208 volts three phase Y connection.

The transformer trailer combination of the present invention with the direct mounting of the associated switches and interconnection thereof provides a very compact enclosed assembly permitting the many different circuit connections desired and thus increase the flexibility and utility of a multiple purpose mobile substation.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the I subject matter which is regarded as the invention.

We claim:

1. In a transformer assembly for selective connection to single phase and three phase electrical lines,

. (a) a plurality of individual single phase transformers each having a primary including a plurality of primary windings and a secondary including a plurality of secondary windings,

(b) a first primary switch means selectively interconnecting said primary windings of each transformer in series and in parallel,

(0) second primary switch means connected to said primary windings to selectively interconnect the primaries of said transformers in a single phase connection and a three phase connection, and

(d) secondary switch means selectively interconnecting said secondaries in a single phase connection and a three phase connection.

2. The transformer assembly of claim 1 having,

(a) a single transformer enclosure defining a single transformer compartment with the plurality of transformers mounted with said compartment.

3. In a single integral transformer unit,

(a) a plurality of single phase transformers each having a primary and a secondary,

(b) switch means interconnecting the primaries of said transformers and having a first position establishing a single phase input connection and a second position establishing a three phase input connection, and

, (c) switch means interconnecting the secondaries of said transformers and having a first position establishing a single phase output and having a second posi tion establishing a three phase output.

4. In a transformer assembly for selective connection to a single phase input and to a three phase input,

(a) a plurality of single phase transformers each having a primary including a plurality of primary windings and a secondary including a plurality of secondary windings,

(b) voltage switch means for selectively connecting said primary windings of each transformer in series and in parallel,

(c) phase switch means connected to said primaries and selectively interconnecting said windings respectively in parallel circuit, in a delta circuit and in a Y circuit, and

(d) output switch means connected to said secondaries and selectively interconnecting the secondaries in a single phase parallel circuit and in a three phase circuit.

5. In a transformer assembly for selective connection to a single phase input and to a three phase input,

(a) a plurality of single phase transformers each having a primary including three primary windings and a secondary including a pair of secondary windings,

(c) phase switch means connected to said primary windings and selectively interconnecting the primaries of said transformer respectively in parallel circuit, in a delta circuit and in a Y circuit, and

(d) output switch means connected to said secondary windings and selectively interconnecting the secondaries in a single phase parallel circuit and in a three phase delta circuit.

6. In a transformer assembly for selective connection to a single phase input and to a three phase input,

(a) a first transformer having a primary including three primary windings and a secondary including a pair of secondary windings,

(b) switch means connected to said primary windings and connecting said windings in series or in parallel, (c) a second transformer having a primary including three primary windings and a secondary including a pair of secondary windings,

(d) a second switch means coupled to the first switch means and connected to said primary windings of said second transformer for establishing similar connections of said two transformers,

(e) phase switch means connected to said primary windings and having three position interconnecting said primaries respectively in a single phase parallel connection, in a three phase open delta connection and in a three phase open Y connection, and

(f) output switch means connected to said secondaries and selectively interconnecting the secondaries in a parallel, single phase output connection and in a delta three phase output connection.

7. In a mobile substation transformer assembly for selective connection to single phase and three phase distribution power lines for providing a temporary power connection,

(a) a plurality of individual single phase transformers each having a primary including a plurality of primary windings and a secondary including a plurality of secondary windings,

(b) first primary switch means interconnecting said primary windings of each transformer in series and in parallel,

() second primary switch means connected to said primaries for selectively interconnecting said pri maries in a single phase input connection and a three phase input connection,

(d) secondary switch means selectively interconnecting said secondaries in a single phase connection and a three phase connection,

(e) a mobile support including an integral transformer enclosure, and

(f) means to support said transformers within said enclosure.

8. The mobile substation transformer assembly of claim 7 wherein,

(a) said mobile support includes a housing having said enclosure forming an integral part thereof and separate primary and secondary switching compartments having the corresponding switch means mounted therein.

9. A mobile transformer unit adapted to be connected to a distribution system, comprising,

(a) transformer means adapted to be connected to establish a single phase and a three phase input and a corresponding single phase and three phase outp (b) a closed housing mounted on the trailer unit and having a pair of spaced vertical walls and an intermediate horizontal wall defining a centrally located transformer compartment and individual primary and secondary switching compartments on opposite sides thereof, said housing including releasably closed outer cover means for said switching compartments,

(c) means to mount said transformer means within the transformer compartment,

(d) a primary switch means mounted in the primary switching compartment for selectively establishing said single phase input and said three phase input, and

(e) a switch means mounted in the secondary switching compartment for establishing said single phase output and said three phase output.

10. A mobile transformer unit adapted to be connected to a distribution system, comprising,

(a) a plurality of single phase transformers each including an individual core means and a plurality of primary and secondary windings,

(b) a closed housing mounted on the trailer unit and having a pair of spaced vertical walls and an intermediate horizontal wall defining a centrally located transformer compartment and individual primary and secondary switching compartments on opposite sides thereof, said housing including releasably closed outer cover means for said switching compartments,

(c) means to mount said transformers within the transformer compartment,

(d) a primary switch means mounted in the primary switching compartment for interconnecting said primary windings for a single phase input and for a three phase input, and

(e) a switch means mounted in the secondary switching compartment for interconnecting said secondary windings for a single phase output and for a three phase output.

11. A mobile transformer unit adapted to be connected to a distribution system, comprising,

(a) a plurality of single phase transformers including individual cores and a plurality of primary and secondary windings,

(b) a trailer unit,

(c) a housing mounted on the trailer unit and having wall means defining a transformer compartment and separate primary and secondary switching compartments with a common wall means therebetween and a cable compartment,

(d) means to mount said transformers within the transformer compartment,

(e) primary bushings mounted in said common wall or roof compartment means,

(f) secondary bushings mounted in said common wall means,

(g) a switch unit mounted on the wall means interconnecting said bushings to said transformers for a plurality of predetermined connections,

(h) a switch unit mounted on the wall means supporting said secondary bushings and interconnecting said bushings to said transformers for a plurality of predetermined connections, and

(i) connecting cables connected to said switch units and extending into said cable compartment for storage.

12. A mobile transformer unit adapted to be connected to a distribution system, comprising (a) a plurality of single phase transformers including individual cores and a plurality of primary and secondary windings,

(b) a trailer unit,

(c) a housing mounted on the trailer unit with a top door means and side door means on opposite side walls thereof, said housing having a pair of spaced walls parallel to said side wall doors and an intermediate top wall joining said spaced walls defining an integral centrally located transformer compartment with switching compartments on opposite sides thereof and a cable compartment above said intermediate top Wall,

(d) means to mount said transformers within the transformer compartment,

(e) primary bushings mounted in one of said walls,

(f) secondary bushings in the opposite of said walls,

(g) a switch unit mounted on the wall supporting said primary bushings and interconnecting said bushings to said transformers for a plurality of predetermined connections,

(h) a switch unit mounted on the wall supporting said secondary bushings and interconnecting said bushings to said transformers for a plurality of predetermined connections, and

13. The mobile transformer unit of claim 12 wherein,

(a) said top door means include a hinged door member projecting vertically upwardly in the open position, and

(b) a warning light secured to the outer end and interior side of the hinged door member for providing a plainly visible warning light during energization of the mobile transformer unit.

14. In a transformer unit, (a) a plurality of primary windings and a plurality of secondary win-dings magnetically coupled thereto, (b) first switch means interconnecting said primary windings to selectively establish a single phase input and a three phase input, and

(c) a second switch means interconnecting said secondary winding to selectively establish a single phase output and a three phase output.

References Cited by the Examiner UNITED STATES PATENTS 726,391 4/1903 Armstrong et al. 323-435 2,476,147 7/1949 Hodnette 317-l4 FOREIGN PATENTS 869,979 11/ 1941 France.

67,037 8/ 1940 Norway.

JOHN F. COUCH, Primary Examiner.

MILTON O. HIRSHFIELD, Examiner. 30 W. E. RAY, Assistant Examiner.

Claims

14. IN A TRANSFORMER UNIT, (A) A PLURALITY OF PRIMARY WINDINGS AND A PLURALITY OF SECONDARY WINDINGS MAGNETICALLY COUPLED THERETO, (B) FIRST SWITCH MEANS INTERCONNECTING SAID PRIMARY WINDINGS TO SELECTIVELY ESTABLISH A SINGLE PHASE INPUT AND A THREE PHASE INPUT, AND (C) A SECOND SWITCH MEANS INTERCONNECTING SAID SECONDARY WINDING TO SELECTIVELY ESTABLISH A SINGLE PHASE OUTPUT AND A THREE PHASE OUTPUT.