GB2050066A

GB2050066A - Electric coil arrangements

Info

Publication number: GB2050066A
Application number: GB8014593A
Authority: GB
Original assignee: Landis and Gyr AG; LGZ Landis and Gyr Zug AG
Current assignee: Siemens Building Technologies AG; Landis and Gyr AG
Priority date: 1979-05-31
Filing date: 1980-05-02
Publication date: 1980-12-31
Also published as: ES257686U; CH642765A5; DE8012982U1; IT1131201B; IT8022432A0; GB2050066B; ES257686Y; FR2458135B1; FR2458135A1

Abstract

A coil arrangement for coils of electric equipment, such as electricity meters, comprises connection lugs 8 in a connection block 7, a casing 1 and an independent coil body 2 which can be connected to the casing 1 carries a coil winding 10 and is made from theroplastic material. The connection lugs 8 which comprise weldable and solderable material are connected to the ends 9 of the coil winding 10 by sandwich welding. The connection lugs 8 each comprise a plate 11 with wing portions 12, which is provided with an opening 20, a flap portion 18 which forms a sandwich- like space with the plate 11, with an opening 13 for connection wires 17, and with a heat barrier 16. <IMAGE>

Description

SPECIFICATION Electric coil arrangements This invention relates to electric coil arrangements particularly, but not exclusively, for use as voltage coils of electricity meters.

The known coil cans for voitage coils of electricity meters are made from thermosetting plastics material, the casing of the coil can and the core of the can forming a unit. The winding which is arranged on winding holders or on a coil body is inserted into the coil can and encapsulated by a casting process. The coil cans are provided with a connection block with connection lugs which are used for soldering the ends of the winding wires of the coil to the connection wires which are passed to the terminals of the electricity meter. Coil cans which are made from thermosetting plastics material are not resistant to fracture and are also expensive. The soldered connections between the ends of the winding and the soldering lug and the soldering lug and the connection wire give rise to a considerable amount of work, particularly when the wires have to be stripped of insulation beforehand.

In the operation of soldering the wires of the winding, the soldering temperature must be kept within narrow limits, and it is not possible to exclude the possibility of corrosion of the soldered connections by the soldering flux used in the soldering operation.

According to the present invention there is provided an electric coil arrangement comprising a casing with a connection block, an independent coil body which can be connected to the casing and which carries a coil winding, the casing and the coil body being made from thermoplastic material, and connection lugs arranged in the connection block and connected by welding to ends of the coil winding.

The invention will now be described by way of example with reference to the accompanying drawing, in which: Figure 1 shows a plan view of a coil can; and Figures 2 to 4 show first, second and third examples of a connection lug on an enlarged scale.

The coil can shown in Fig. 1 comprises a casing 1 and a separate coil body 2 of which one end can be form-lockingly or positively inserted into an opening in the bottom of the casing 1. On both ends, the coil body 2 carries arms 3 and 4 between which the winding is arranged, with the arms 4 being guided in associated grooves 5 in the casing 1 when the coil body 2 is fitted into the casing 1.

Disposed at the free end of the coil body 2 is a holder 6 for the winding ends 9 of the coil winding 10. Provided on the casing 1 of the coil can, opposite the holder 6, is a connection block 7 in which are disposed the connection lugs 8 which are provided for connecting the ends 9 of the winding 10 which is wound directly on the coil body 2, to terminals (not shown) of an electricity meter.

The coil can together with the coil body 2 comprises thermoplastic material; and insulated copper wire is used for the winding 10.

The connection lug 8 shown in Fig. 2, which is made from special bronze, in the form of a punched-out plate 11, is provided with two wing or lobe portions 12, in its upper part which serves for the internal connections of the ends 9 of the winding 10. The other end of the connection lug 8 is provided with a tetragonal opening 1 3 which has a slot 14, thereby forming two shoulder portions 1 5. A hole 1 6 provided above the opening 1 3 in the plate 11 serves as a heat barrier means which prevents the thermoplastic coil can fom becoming soft in the operation of soldering the connection wires 1 7 which lead to the terminals of the equipment.Between the wings 1 2 and the hole 16, the connection lug 8 has a bent-over flap portion 1 8 which, with the plate 11, forms a sandwich-like space.

The end 9 of the winding 10, which is held in the holder 6 (Fig. 1) of the coil body 2 is passed through an opening 20 at the edge of the plate 11 and under the flap portion 18, and wound around one of the wing portions 12. In this way the end 9 of the winding 10 is fixed in the correct position for automatic welding.

Welding of the ends 9 of the winding 10 to the connection lugs 8 is effected by a doublepulse resistance welding process wherein the insulation on the end 9 of the winding 10 is removed with the first pulse and the weld connection in the sandwich between the flap portion 1 8 and the plate 11 is made with the second pulse.

The connection of the connection wire 1 7 as the connection between the connection lug 8 and the terminal of the equipment is effected as previously by soldering, wherein a stripped portion of the connection wire 1 7 is fitted into the slot 1 4 of the opening 1 3 in such a way that the end of the connection wire 1 7 bears against the reverse side of the plate 11. The insulated part of the end of the connection wire 1 7 is thus pressed into a notch 19 (Fig. 1) in the connection block 7 so that, before the soldering operation, the connection wire 1 7 is firmly held in the opening 1 3 in the connection lug 8.In this way the person assembling the arrangement has both hands free to carry out the soldering operation.

The examples of the connection lug 8 shown in Figs. 3 and 4 differ from the structure shown in Fig. 2 only by virtue of a different configuration in the sandwich-like space for receiving the end 9 of the coil winding 10, insofar as the connection be tween the flap portion 1 8 and the plate 11 extends horizontally, with the flap portion 1 8 in Fig. 3 lying above the horizontal connection while the flap portion 1 8 in Fig. 4 is below the horizontal connection.

If required, the external connection of the connecting lug 8 to the terminal of the electrical equipment can also be effected by means of two connection wires 1 7 (see Fig. 4), stripped portions thereof being fitted over the shoulder portions 1 5 into the opening 1 3 in such a way that the ends thereof bear against the reverse side of the plate 11, with the insulated portions of the connection wires 1 7 being fixed in two notches 1 9 in the connection block 7 before the soldering operation.

Manufacturing the coil can from thermoplastic material by separate injection processes for the casing 1 and the coil body 2 results in longer tool lives and thus lower manufacturing costs, and also makes it possible for the winding 10 to be wound directly on the coil body 2, giving savings in respect of copper wire. The use of the sandwich welding process for the internal connection between the winding wire and the connection lug 8 eliminates the previous danger of corrosion due to the soldering flux used, and also eliminates the difficulty involved in maintaining the soldering temperature. In addition, the operation of soldering the connection wires 1 7 into place does not influence the internal weld conection. Fixing the ends 9 of the winding 10 by means of the wings 1 2 permits automatic welding. Fixing the connection wires 1 7 in the slot 1 4 or to the shoulder portions 1 5 and in the notches 1 9 (Fig. 4) permits the person assembling the arrangement to use both hands for the soldering operation. The heat barrier means prevents heat from flowing to the thermoplastic casing 1 of the coil can during the solder operation.

The special bronze which is used for the connection lugs 8 can both be satisfactorily welded and also satisfactorily soldered; there is no need for a preliminary surface treatment.

Using thermoplastic material for the coil can gives rise to the advantage that the entire coil can be pressed on to a voltage core of the equipment, which may be an electricity meter, so that there is no need for the wedging operation which was required hitherto.

Claims

1. An w octric coil arrangement comprising a casing 'with a connection block, an indepen dent coil body which can be connected to the casing and which carries a coil winding, the casing and the coil body being made from thermoplastic material, and connection lugs arranged in the connection block and con nected by welding to ends of the coil winding.

2. An arrangement according to claim 1 wherein the coil winding is wound directly on the coil body.

3. An arrangement according to claim 2 wherein the coil winding is wound between arms which are provided at both ends of the coil body and arms which enter grooves in the casing.

4. An arrangement according to claim 1 wherein each connection lug comprises a plate which is provided with wing portions, and with an opening and with a flap portion which with the plate forms a sandwich-like space in which the end of the winding, which is taken through the opening and wound on one of the wing portions, is connected by welding to the connection lug, and wherein the plate also has an opening for fixing at least one connection wire by soldering.

5. An arrangement according to claim 4 wherein the opening has a slot for receiving a connection wire and two shoulder portions for securing two connection wires, wherein the connection wires are held in associated notches of the connection block.

6. An arrangement according to claim 4 wherein the connection lug is provided with a heat barrier.

7. An arrangement according to claim 4 wherein each connection lug is made from material which can be soldered and welded without previous surface treatment.

8. A coil arrangement according to claims 1 and 2 of the accompanying drawing.

9. A coil arrangement according to Figs. 1 and 3 of the accompanying drawing.

1 0. A coil arrangement according to Figs.

1 and 4 of the accompanying drawing.