GB1576786A

GB1576786A - Tap switch attachment for a tapped transformer

Info

Publication number: GB1576786A
Application number: GB10396/78A
Authority: GB
Original assignee: Maschinenfabrik Reinhausen Gebrueder Scheubeck GmbH and Co KG
Current assignee: Maschinenfabrik Reinhausen Gebrueder Scheubeck GmbH and Co KG
Priority date: 1977-03-22
Filing date: 1978-03-16
Publication date: 1980-10-15
Also published as: NL7802925A; JPS53117712A; SE7803151L; SE415810B; AU515962B2; FR2385201A1; BE865155A; DE2712484A1; CA1092693A; AU3423778A; IN148169B; FR2385201B1

Description

(54) A TAP SWITCH ATTACHMENT FOR A TAPPED TRANSFORMER (71) We, MASCHIHENFABRIK REIN HAUSEN GEBRÜDER SCHEUBECK G.m.b.H. & Co. KG, of Falkensteinstrasse 8, 8400 Regensburg, Federal Republic of Germany, a Kommanditgesellschaft organised under the laws of the Federal Republic of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to a tap switch attachment for a tapped transformer.

Tap switches are known from, for example, DT-AS 18 02 303. In conventional tap switches, the oil spaces of transformer and tap switch are usually separated by means of a lead-through plate which sits in the flange opening of the tap switch.

This lead-through plate also carries special connecting contacts, to which the ends of the winding parts of the tapped winding are connected. If necessary, further connecting lines, which connect the connecting contacts of the lead-through plate with the actual tap contacts of the attachment tap switch, are installed within the tap switch.

The lead-through plate must satisfy very high requirements in two respects; i.e. it must be mechanically rigid and oil-tight, and it must also provide high electrical protection to prevent electrical flash-overs between itself and the connecting contacts carried by it. For this reason, the leadthrough plate is generally still provided with ribs or other protrusions which run around the connecting contacts.

In an improved tap switch the hereinbefore-mentioned lead-through plate is not required. However, a difficulty with this tap switch resides in the various connections provided between the ends of the winding and the tap contacts, which are after all arranged around the cylinder in one plane for each phase. The connection of the ends of the lines to the tap contacts can only be undertaken with great difficulty, and therefore, the ends of the winding parts must have a length which is adequate for this purpose.

According to the present invention there is provided a tap switch attachment for a tapped transformer, comprising a main housing provided with a lateral opening connectible to a lateral opening associated with a tapped transformer, a tap switch mounted within an oil-tight housing which is contained in the main housing, the tap switch being provided with a plurality of tap contacts, a frame arranged in the lateral opening of the main housing and carrying at least one mounting strip, and a plurality of conductors each for connection to the tapped transformer, one portion of each one of the conductors being connected to a respective one of the tap contacts, and another portion of each one of the conductors being mounted to the or one of the mounting strips.

The oil-tight housing may be substantially cylindrical, and the tap switch may comprise a load selector. The main housing may comprise a corresponding cylindrically shaped portion, the oil-tight housing being arranged in the corresponding cylindrically shaped portion of the main housing, and the lateral opening of the main housing extending in a general plane which is substantially parallel to a plane containing the cylindrical axis of the substantially cylindrical oil-tight housing.

The main housing may be provided with flange means adjacent the lateral opening, the flange means being attachable to corresponding flange means associated with the tapped transformer.

Preferably, the tap switch is arranged to operate as a three-phase tap switch.

The frame may carry a respective mounting strip for each phase of the tap switch, the or each mounting strip comprising a plurality of slots each receiving a respective one of the other portions of the plurality of conductors. Advantageously, the or each mounting strip may be elongate in a direction perpendicular to the length direction of the oil-tight housing.

Each one of the plurality of conductors may comprise an insulated conductor and a respective crimping sleeve may be- prsW vided on the bared extremity of the other portion of each one of the conductors.

The oil-tight housing may be disposed on a base portion of the main housing, the base portion being provided with an opening for maintenance of the tap switch, and with a lid normally closing the base portion opening.

Advantageously, a tap switch attachment embodying the invention may be simply manufactured and the ends of the individual parts of the tap windings coming from the transformer may be connectible in simple manner with good accessibility.

An embodiment of the invention to be described in detail hereinafter may be used with- the widely spread and tested cylindrical installation load selectors. Thus, special precautions for the separation of the oil volumes of transformer and load selector are not required. Furthermore, in spite of the absence of a lead-through plate, an ordered and easy connection of the ends of the winding parts to the tap switch may be effected. The ends of the connecting lines to the individual tap contacts ate, preferably, in rows on the mounting strips and lie directly in the flange opening of the attachment tap switch and are thus easily accessible. The individual phases of the three-phase tap switch may be associated with respective mounting strips and may be positively separated and insulated from one another by clean oil paths so that surface leakage currents between the phases cannot develop. Furthermore, the ends of the connecting lines, which are fastened to the mounting strips and already stripped of insulation, may be provided with a crimp sleeve so that the connection with the ends of the winding parts can be executed as crimp connection.

An embodiment of the present invention will now be more particularly described by way of example with reference to the ac companying drawings, in which: Fig. 1 shows a schematic side elevation partly in section of a tap switch attachment according to the said embodiment, Fig. 2 shows an elevation of the flange opening of the tap switch attachment of Fig. 1, and Fig. 3 shows a cross-section through the tap switch attachment of Fig. 1.

Referring now to the drawings, there is shown a tap switch attachment comprising a housing 1, which is matched to the cvlindrical shape of a three-phase cylindrical load selector 3, and which is provided with a lateral flange opening 2. The three-phase cylindrical load selector 3 is arranged in the flange opening 2 and is suspended in the housing 1 and held by a tap switch head 4.

A motor drive 5, which is flanged to the housing I and which is connected through a coupling linkage 6 with the gearing of the attachment tap switch arranged in the tap switch head 4 is not more closely illustrated.

The flange opening 2 of the attachment tap switch is intended for attachment to an equally large flange opening 7 of a transformer. A frame, which is provided with three horizontal mounting strips 8, is arranged in the flange opening 2 of the attachment tap switch. Each mounting strip is associated with a respect phase of the load selector 3 and possesses a plurality of notches 10 corresponding to the number of tap contacts 9 of the corresponding phase.

The ends 11 of connecting lines 12, which are connected with the tap contacts 9 arranged at the periphery of the load selector 3 are positioned into these notches 10. The ends 11 of the connecting lines 12 projecting beyond the mounting strips 8 are strip ped of insulation and each is provided with a respective crimp sleeve 13 so that the connection can be executed in a simple manner as a crimp connection with the not illustrated conductor ends of the winding parts.

The load selector 3 may be carried solely by the tap switch head 4 as is usual in the installation technique. It may however also be placed in a particularly expedient manner on the bottom 14 of the housing 1.

In this case, an additional maintenance opening 15, which is closed by a lid 16 and which serves for maintenance of the load selector 3, may be provided at the bottom 14. Thus, advantageously, the load selector is accessible at the same time from below and above for its maintenance.

WHAT WE CLAIM IS: - 1. A tap switch attachment for a tapped transformer, comprising a main housing provided with a lateral opening connectible to a lateral opening associated with a tap ped transformer, a tap switch mounted within an oil-tight housing which is contained in the main housing, the tap switch being provided with a plurality of tap contacts, a frame arranged in the lateral opening of the main housing and carrying at least one mounting strip, and a plurality of conductors each for connection to the tapped transformer, one portion of each one of the coductors being connected to a respective one of the tap contacts and another portion of each one of the conductors being mounted to the or one of the mounting strips.

2. An attachment as claimed in claim 1, wherein the oil-tight housing is substantially cylindrical, and the tap switch comprises a load selector.

3. An attachment as claimed in claim 2, wherein the main housing comprises a

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. vided on the bared extremity of the other portion of each one of the conductors. The oil-tight housing may be disposed on a base portion of the main housing, the base portion being provided with an opening for maintenance of the tap switch, and with a lid normally closing the base portion opening. Advantageously, a tap switch attachment embodying the invention may be simply manufactured and the ends of the individual parts of the tap windings coming from the transformer may be connectible in simple manner with good accessibility. An embodiment of the invention to be described in detail hereinafter may be used with- the widely spread and tested cylindrical installation load selectors. Thus, special precautions for the separation of the oil volumes of transformer and load selector are not required. Furthermore, in spite of the absence of a lead-through plate, an ordered and easy connection of the ends of the winding parts to the tap switch may be effected. The ends of the connecting lines to the individual tap contacts ate, preferably, in rows on the mounting strips and lie directly in the flange opening of the attachment tap switch and are thus easily accessible. The individual phases of the three-phase tap switch may be associated with respective mounting strips and may be positively separated and insulated from one another by clean oil paths so that surface leakage currents between the phases cannot develop. Furthermore, the ends of the connecting lines, which are fastened to the mounting strips and already stripped of insulation, may be provided with a crimp sleeve so that the connection with the ends of the winding parts can be executed as crimp connection. An embodiment of the present invention will now be more particularly described by way of example with reference to the ac companying drawings, in which: Fig. 1 shows a schematic side elevation partly in section of a tap switch attachment according to the said embodiment, Fig. 2 shows an elevation of the flange opening of the tap switch attachment of Fig. 1, and Fig. 3 shows a cross-section through the tap switch attachment of Fig. 1. Referring now to the drawings, there is shown a tap switch attachment comprising a housing 1, which is matched to the cvlindrical shape of a three-phase cylindrical load selector 3, and which is provided with a lateral flange opening 2. The three-phase cylindrical load selector 3 is arranged in the flange opening 2 and is suspended in the housing 1 and held by a tap switch head 4. A motor drive 5, which is flanged to the housing I and which is connected through a coupling linkage 6 with the gearing of the attachment tap switch arranged in the tap switch head 4 is not more closely illustrated. The flange opening 2 of the attachment tap switch is intended for attachment to an equally large flange opening 7 of a transformer. A frame, which is provided with three horizontal mounting strips 8, is arranged in the flange opening 2 of the attachment tap switch. Each mounting strip is associated with a respect phase of the load selector 3 and possesses a plurality of notches 10 corresponding to the number of tap contacts 9 of the corresponding phase. The ends 11 of connecting lines 12, which are connected with the tap contacts 9 arranged at the periphery of the load selector 3 are positioned into these notches 10. The ends 11 of the connecting lines 12 projecting beyond the mounting strips 8 are strip ped of insulation and each is provided with a respective crimp sleeve 13 so that the connection can be executed in a simple manner as a crimp connection with the not illustrated conductor ends of the winding parts. The load selector 3 may be carried solely by the tap switch head 4 as is usual in the installation technique. It may however also be placed in a particularly expedient manner on the bottom 14 of the housing 1. In this case, an additional maintenance opening 15, which is closed by a lid 16 and which serves for maintenance of the load selector 3, may be provided at the bottom 14. Thus, advantageously, the load selector is accessible at the same time from below and above for its maintenance. WHAT WE CLAIM IS: -

1. A tap switch attachment for a tapped transformer, comprising a main housing provided with a lateral opening connectible to a lateral opening associated with a tap ped transformer, a tap switch mounted within an oil-tight housing which is contained in the main housing, the tap switch being provided with a plurality of tap contacts, a frame arranged in the lateral opening of the main housing and carrying at least one mounting strip, and a plurality of conductors each for connection to the tapped transformer, one portion of each one of the coductors being connected to a respective one of the tap contacts and another portion of each one of the conductors being mounted to the or one of the mounting strips.

3. An attachment as claimed in claim 2, wherein the main housing comprises a

corresponding cylindrically shaped portion, the oil-tight housing being arranged in the corresponding cylindrcially shaped portion of the main housing, and the lateral opening of the main housing extending in a general plane which is substantially parallel to a plane containing the cylindrical axis of the substantially cylindrical oil-tight housing.

4. An attachment as claimed in any one of the preceding claims, wherein the main housing is provided with flange means adjacent the lateral opening, the flange means being attachable to corresponding flange means associated with the tapped transformer.

5. An attachment as claimed in any one of the preceding claims, wherein the tap switch is arranged to operate as a threephase tap switch.

6. An attachment as claimed in any one of the preceding claims, wherein the frame carries a respective mounting strip for each phase of the tap switch, the or each mounting strip comprising a plurality of slots each receiving a respective one of the other portions of the plurality of conductors.

7. An attachment as claimed in claim 6, wherein the or each mounting strip is elongate in a direction perpendicular to the length direction of the oil-tight housing.

8. An attachment as claimed in any one of the preceding claims, wherein each one of the plurality of conductors comprises an insulated conductor and a respective crimp ing sleeve is provided on the bared extremity of the other portion of each one of the conductors.

9. An attachment as claimed in any one of the preceding claims, wherein the oiltight housing is disposed on a base portion of the main housing, the base portion being provided with an opening for maintenance of the tap switch and with a lid normally closing the base portion opening.

10. A tap switch attachment for a tap ped transformer, substantially as hereinbefore described with reference to the accompanying drawings.