US1768256A - Transformer - Google Patents

Description

June 24, 1930. .G. E. JANSSON TRANS FORMER Filed May 12, 1927 2 Sheets-Sheet l 24, 1930. JANSSON 1,768,256

TRANSFORMER Filed May 12, 1927 2 Sheets-Sheet 2 A W gjlw Jhverc 707? Patented June 24, 1930 UNITED STATES PATENT OFFICE GUSTAV E. JANSSON, OF WOLLASTON. MASSACHUSETTS, ASSIGNOR TO CONDIT ELEG- TRICAL MANUFACTURING CORPORATION, OF SOUTH. BOSTON, MASSACHUSETTS, A

' CORPORATION or MASSACHUSETTS TRANSFORMER Application filed May 12,

This invention relates to transformers adapted for use on high tension transmission lines to supply power to auxlhary devices such as ammeters, relays and the like adapted to control the high tension line.

i The invention has particular reference to so-called current transformers which are adapted to supply ammeters to measure the current in the high tension line and to supm ply small amounts of power for actuating instruments, tripping coils and the like. The design of a transformer for such purposes presents the problem of great difliculties. Since the primary of a transformer must be connected wit-h the high tension line, the primary must be insulated from the secondary cessitates the use of expensive insulating bushings for the high tension leads. If the transformer is placed indoors, further insulation must be provided between the incoming and outgoing leads and the building structure.

It is an object of this invention to provide a transformer, and particularly a current transformer, of a novel constuction wherein appropriate insulation is provided between the high tension primary and the low tension secondary in an exceedingly effective although simple and inexpensive manner and wherein the necessity for expensive bushings and the like is obviated.

It is a further object of the invention to in sert the transformer directly in the high tension circuit as by suspending it therefrom and to lead the low tension conductors down from the vicinity of the high tension to the instruments or control devices.

A yet further object of the invention is the rovision of a string of insulator units which 5 15 adapted to withstand the full line poten 1927. Serial No. 190,862.

tial, with each insulator of the string characterized by having a transformer therein with the insulation of the insulator forming the insulation between the primary and secondary and also the core. of the transformer and with the primary of the first transformer connected to the high tension line and with the secondaries and primaries of succeeding transformers interconnected in cascade and with the secondary of the last transformer adapted for connection with the instruments or the like. As thus arranged, the insulation between the primaries and the secondaries of the insulator-transformers are arranged in series and, while the insulation of one insulator is insufficient to withstand full line potential, the insulation of all of the insulators issufficient to insulate the last low tension secondary from the high tension line.

A further object of the invention is the provision of a multi-unit suspension-type transformer especially adapted for outdoor installation.

A still further object is the provision of a suspension type transformer unit having suitable connecting means whereby a number of units may be connected in series to increase the insulation between the transmission line and the control circuit to be energized.

' A further object .is the provision of an improved construction for an auxiliary transformer which will be reliable in service and economical in manufacture and installation.

A further object is generally to improve the methods and apparatus of deriving low tension power from high tension transmission lines.

Fig. 1 is a side elevation partly in section of a current transformer embodying the in- Fig. 7 is a view illustrating the manner in V transformer.

which the transformer can be connected directly in the high tension line.

As here shown, the invention consists of a plurality of insulators 10 arranged in a suspension string as shown in Figs. 1 and 2. Each insulator is composed of porcelain and has a petticoat 12 and a yoke 14 by which the insulator is suspended. The yoke is integral with the petticoat at its ends and in the middle is spaced above the petticoat to provide a horizontally elongated slot or opening 15 through which the primary winding of the transformer is passed. The yoke is provided with an internal semi-circular passage 16 therein in which an approximately semicircular shaped transformer core 18 is received. The ends of the core are open and are adapted to be bridged by a straight core piece 20 which is connected with the ends of the semi-circular core by bolts 22 or in any other suitable manner to form a closed magnetic circuit.

The arrangement of the passage 16 and the semi-circular core 18 is such that the core can be inserted in place in the passage and will be retained therein when the separate straight core piece 20 is fastened to the ends thereof. The middle portion 24 of the yoke above the slot 15 is adapted to receive the primary winding of the transformer. The top insulator of the string is provided with transformer winding 26 which is adapted to be directly connected in series with the high tension transmission line A as shown in Fi 7. A supporting strap 28 engages the yo e to support the string of insulators. The strap preferably is made of two parts 28 as shown in Fig. 4 with the lower ends spaced apart beneath the yoke so that the strap does not form a closed electrical circuit about the yoke. The secondary of the transformer is disposed on the straight core piece 20. In the construction illustrated in Fig. 1 the secondary winding comprises a strap 30 which is disposed about the straight core piece 20 and also about the yoke 14 of the next lower insulator of the string and the ends of the strap are connected together mechanically and electrically by the bolt 32, see Fig. 3, which bolt is insulated from the strap, and an insulatin strip 34 is interposed between the opposite sides of the strap at the bolt to prevent short circuiting thereof. The strap thus comprises a single turn secondary winding of the first insulator-transformer and also a single turn primary winding of the next lower insulator- The strap 30, in addition to comprising the primary and secondary windings of the two transformers also comprises the suspension support connecting one transformer with the other. The construction of the various insulator-transformers in the string down to the lowermost may be the same. The lowermost transformer, however, is provided with a low tension multi-turn secondary winding 36, the leads of which are adapted to extend to the instrumentsor control apparatus.

The thickness of the insulating material in each yoke serves to insulate the primary winding from the core and consequently from the secondary winding of each transformer. Since there are a number of insulators in series between the high tension winding 26 of the uppermost unit and the lower tension secondary winding of the lowermost unit and the insulating yokes 14 are in series between the windin the amount of insulation between the hlgh tension and low tension winding is very great, although the insulation provided by each unit by itself would be insuflicient to withstand the total amount of potential; and each insulator consequently is under but a moderate stress. For instance, if each insulator can safely withstand a potential stress of 20,000 volts, then there will be five or six insulator units in series for a 100,000 volt line. As many insulator units will be used as it will be found necessary for any particular voltage.

The transformation ratio of the intermediate units of the string is not of any particular importance so far as the transfer of energy down the string is concerned since the number of ampere-turns remains the same whether the primaries or secondaries of the intermediate units are each composed of one turn or many turns.

The wound secondary 36 of the lowermost unit will ordinarily have more turns than the primary winding 26 and the ratio of the turns of the two windings determines the transformation ratio of the unit.

The arrangement of Fi 2 is essentially the same as in Fig. 1 except t at each unit is provided with a-wound or multi-turn primary and secondary windin 40 and 38 respectively, the prlmary an secondary windings of adjacent transformers being connected in series. With this arrangement, the total transformation ratio of the unit can be divided between the separate sections which, in some instances, may be desirable. The intermediate insulators of the unit of Fig. 2 are supported by independent straps one of which is shown in Fig. 6 as comprising two similar and opposed yoke members 42 which have reflexed ends that are clamped over the core 20 by rivets 44 or other suitable means. The ends of the straps are separated so as to avoid a closed metallic circuit. The yokes 14 of the intermediate insulators are each provided with a supporting strap 46 which may be identical with the strap 28 and the strap is secured preferably loosely to the yoke 42 so that the insulators of the unit are more or less flexibly connected. The same is true of the construction of Fig. 1 slnoe the semi-circular yoke 18 can rock in the recesses of the insulators.

, the insulating bar 48 and is suspended therebelow. The lower end of the insulator-transformer string may be anchored by means of a tie cable 56 to an arm 58. The high tension conductors or leads 60 of the/primary of the first transformer of the string are connected with the ends of the high tension conductor while the low tension leads 62 from the secondary of the last transformer may be extended to suitable control apparatus.

I claim:

1. A combined high tension transformer and insulating unit consisting of a plurality of insulator-sections arranged in series relation, each section having a transformer comprising a core, and primary and secondary windings associated with it, with the secondary winding of one transformer connected to the primary winding of an adjacent transformer and the insulating section interposed between the primary and secondary windings of its transformer and also between the primary winding of its transformer and the primary winding of the adjacent transformer.

2. The combination of a string of suspension cape insulators each having a built-in transformer comprising a corevand a primary and a secondary, the primary being insulated from the core through the cape insulation of the insulator and the secondaries being con-' nected with the primaries of adjacent transformers, the capes of the insulators over lying and enclosing the transformers thereof and the insulation of the insulators being interposed between the'primaries of successive' transformers.

3. The combination of a string of cape ininsulators each having therein and enclosing a transformer comprising a core, a primary and a secondary, means directly connecting each insulator with the core of the next uppermost transformer, and means connecting the secondary Winding of an upper insulator with the primary winding of the next lower insulator.

4. A suspension type transformer includ ing an insulating body having a laterally extended insulating cape, acore member disposed within said body and exposed only below said" cape, and primary and secondary coils surrounding said core and spaced apart by said insulating cape, at least one of said coils being insulated from said core.

5. In a suspension type transformer,-'the combination of a molded insulator body having an integral outstanding flange, a core disposed within said body, primary and secondarycoils surrounding said core, and oppositely directed strain members carried by said insulator body and said core and disposed on opposite sides of said flange.

6. In a transformer, the combination of a strain insulator having a U-shaped member adapted to enclose an iron core, and an integral outstanding cape overhanging said core, primary and secondary COIlS surrounding said core and spaced apart by said cape,

and means including the U-shaped member of said insulator 'to isolate electrically one of said coils from said core and the other coil.

' 7. In a transformer, the combination of a porcelain body having an arcuate internal passage, a substantially ring-shaped core arranged to occupy said passage, a second passage extended laterally through said body at right angles to the plane of said core and arranged to lie within the circumference of said first passage, a primary coil disposed about said core and arranged to pass through said second passage, and a secondary coil disposed about said core, and means including said porcelain body to insulate said coils from each other and also to insulate at least one of said coils from said core.

8. In a transformer, the combination of a plurality of transformer units, each compris-. ing a core and primary and secondary coils, and means including a rigid connect-ion comprising also the primary winding of one unit and the secondary winding of the next to connect said units electrically together and to suspend said units fixedly one from the other.

9. Asuspension transformer including an insulating body having a yoke and an integral cape disposed beneath and carried by the ends of said yoke, said insulating bodyhaving a passage therein open at both ends beneath said cape and extended longitudinally through said yoke and conforming substantially with the exterior configuration thereof, a core disposed mainly beneath said cape and extended above said cape and through the passage in said yoke, a Winding disposed transversely to and surrounding said yoke and the core therein, and a second winding disposed about'said core and'beneath said cape.

10. Asuspension transformer including a molded insulating body having a substantially arcuate yoke portion, an integral cape portion disposed beneath and carried by the ends of said yoke portion and extended laterallyjin all directions therebeyond, sald yoke-portion having-a longitudinal passage there'through which extends through and 1s open at both ends beneath said cape, a core disposed mainly beneath said cape and having a portion thereof lying within said passage, a current-conducting loop encircling said yoke portion and disposed wholly above said cape portion, and a second current-conducting loop encircling said core and disposed wholly beneath said cape portion.

11. A suspension transformer including a molded insulating body having a substantially arcuate yoke portion, an integral cape portion disposed beneath and carried by the ends of said yoke portion and extended laterally therebeyond in alldirections, said insulating body having a passage therethrough which is open at both ends beneath said cape portion and extends through said yoke portion, a closed magnetic core extended through said passage and therebelow having a portion thereof exposed beneath said cape, a current conducting loop encircling said yoke and core transversely thereof and lying entirely above said cape, and a second current conducting loop encircling the exposed portion of said core and lying entirely beneath said cape.

12. A transformer unit for a suspension transformer including a molded insulating body having a substantially arcuate yoke portion, an integral cape portion disposed beneath and carried by the ends of said yoke portion and extended laterally therebeyond in all directions, said insulating body having a passage therethrough which is open at both ends beneath said cape portion and extends through said yoke portion, a closed magnetic core extended through said passage and therebelow having a portion thereof exposed beneath said cape, a current conducting loop encircling said yoke and core transversely thereof and lying entirely above said cape, and a second current conducting loop encircling the exposed portionof said core and lying entirely beneath said cape, said conducting loop comprising the supporting means for the unit, and said second loop comprising a support for the next unit below.

13. A suspension transformer including a molded insulating body having a substantially arcuate yoke portion, an integral cape portion disposed beneath and carried by the ends of said yoke portion and extended laterally therebeyond in all directions, said insulating body having a passage therethrough which is open at both ends beneath said cape portion and extends through said yoke portion, a closed magnetic core extended through said passage and therebelow having a portion thereof exposed beneath said cape, a current conducting loop encircling said yoke and core transversely thereof and lying entirely above said cape, and a second current-conducting loop encircling the exposed portion of said core and lying entirely beneath said cape, said conducting loop comprising the supporting means for the unit, and said second loop comprising a support for the next unit below, said conducting loops also comprising the primary and secondary coils of the transformer unit. 14. A high tension transformer comprising a plurality of insulator units, each unit including a U-shaped yoke portion, an integral laterally extended cape portion, a core disposed mainly below and entirely within the lateral confines of said cape and having a leg thereof conforming with and extended longitudinally through said U-shaped yoke, and a primary winding disposed above said cape and transversely surrounding said U- shaped yoke and the enclosed leg of said core, the several insulating units of said transformer being connected in superposed order through said cores, and each core having a secondary disposed beneath said cape and electrically connected with the primary of the adjacent transformer.

In testimony whereof, I have signed my name to this specification. i

GUSTAV E. JANSSON.

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