CN1269149C - Electrical device and method of forming an electrical device - Google Patents

Abstract

An enclosed transformer assembly (20) includes a transformer (30) enclosed in a transparent electrically insulating housing (32, 34). The transparent enclosure is susceptible to heat exchange so that it can operate more efficiently in use.

Description

Electrical device and method of forming an electrical device

technical field

The present invention relates to transformers and other electrical devices including transformers, such as power supply devices, and methods of forming electrical devices.

Background technique

It is known to electrically insulate transformers by concentrating them in an opaque plastic enclosure, wherein the plastic enclosure is substantially in line, and to fill the area between the transformer and the inner walls of said enclosure with an opaque insulating material shape and have an open bottom. The material generally forms a concave bottom wall in the area between the transformer and the bottom of the enclosure. Transformers generate heat when in use, which cannot be effectively dissipated since neither the shield nor the dielectric insulation material can effectively transmit the heat. This can cause damage to the transformer, or at least can cause high electrical losses. This problem is also encountered in other devices including transformers, such as power supply devices.

Furthermore, the above-mentioned transformer arrangement is usually mounted on a printed circuit board via a plurality of legs extending from the electrical terminals of the transformer to beyond the above-mentioned bottom region of the cover. The cover is usually mounted in close proximity to the circuit board, with the result that a cavity is formed between the circuit board and the aforementioned bottom wall. In use, due to temperature changes in the cavity, air containing moisture enters and collects in the cavity, and over time, the moisture can cause damage to the printed circuit board.

purpose of invention

It is therefore an object of the present invention to provide an electrical device and a method of forming such an electrical device by which the Applicant believes at least to alleviate the above disadvantages.

Summary of the invention

According to the present invention, an electrical device is provided, comprising a transformer and a permanent translucent or transparent electrically insulating housing, so that the heat generated by the transformer is transmitted outward through said cover, characterized in that said housing It has the same shape as the transformer described above.

The cover is preferably transparent. The transformer also includes a transparent bobbin on which the transformer iron core and the transformer winding are installed.

In one embodiment, the casing constitutes a thin shell.

The housing includes a transparent outer shell of rigid material and a layer of transparent filling material filled between the shell and the transformer. The housing may include first and second housing halves mounted together to form the housing.

The housing may include outwardly extending protrusions to provide a clearance between the housing and a surface on which the device is mounted in use.

In another embodiment, the housing may be box-shaped and may include a plurality of plugs that mate with and make electrical contact with conventional socket means.

The transformer may form part of power circuitry which may include a first output accessible through the cover. The power supply circuitry may further include a second output connected in parallel to the first output and also accessible through the shroud.

The electrical circuitry may include a fuse, preferably located in a recess in the housing.

The cover may include a cover for opening and closing the recess.

According to the present invention, there is also provided a method of forming an electrical device, said method comprising the steps of: providing a transformer; and permanently enclosing said transformer in a transparent or translucent electrically insulating housing, The casing has the same shape as the transformer, so that the electrically insulating casing transmits the heat generated by the transformer to the outside during use.

Preferably, the transformer is placed by installing the transformer in the casing such that a small gap is formed between the entire outer surface of the transformer and the casing; the gap is filled with transparent electrically insulating material so as to position the transformer.

Brief description of the drawings

The invention will now be further described only on the basis of the embodiments of the accompanying drawings:

The schematic perspective view of the transformer device of Fig. 1 prior art;

Figure 2 is a schematic exploded perspective view of a transformer arrangement according to the invention;

Figure 3 is a schematic perspective view of the assembled device in Figure 2;

Fig. 4 is a top schematic perspective view of a power supply device according to the present invention;

Fig. 5 is a bottom schematic perspective view of the power supply unit; and

The basic block diagram of the power supply device of Fig. 6 Fig. 4;

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

In FIG. 1 , a prior art transformer arrangement is generally indicated at 10 . The device comprises a transformer (not shown) mounted in an opaque enclosure 12 having an open bottom 14 . A stack of opaque thermoset epoxy 16 is placed in the enclosure embedding the transformer, thereby electrically insulating the transformer and permanently placing the transformer in the enclosure.

Four conductive legs 18 connected to transformer terminals (not shown) extend beyond the concave bottom wall 17 formed of resin and also beyond the open bottom 14 of the housing, said legs 18 serving to connect the The transformer is connected to external circuitry (also not shown).

Disadvantages of this device refer to the preamble of the description.

In FIG. 2 the transformer arrangement according to the invention is generally designated 20 . The device comprises a transformer 30 comprising a transparent bobbin 22 of a suitable plastic material. A stack of sheets 23 of magnetic material is stacked around and extending along the bobbin to form the magnetic core of the transformer. The primary winding 24 and the secondary winding 26 of the transformer are provided on the bobbin in a known manner. But there is no insulating tape placed around the windings as in some known transformers and transformer arrangements. Conductive legs 28 are connected to input and output terminals (not shown) of said transformer 30 .

The device also includes first and second housing halves 32, 34 of a translucent, preferably transparent, durable housing 31 (shown in FIG. 3 ) formed of suitable Made of rigid plastic material. The two housing halves together form the housing, which has a shape and profile substantially similar to the general outline of the transformer 30 . When assembled, a small gap is formed between the housing 31 and the transformer 30 enclosed thereby. The second housing half 34 forms an opening 36 in its central region.

When assembling the device, after the housing 31 is brought together by clamping the housing halves 32 and 34 together, a transparent thermosetting material is introduced into the housing through the opening 36 to fill the void, To form a thin layer between the transformer and the casing to discharge the gas in the casing. The material may be placed into opening 36 by a suction mechanism and procedure. The material is then allowed to cure.

The device thus comprises a thin transparent housing 38 (shown in FIG. 3 ) suitable for the transformer, said housing 38 consisting of said transparent layer 37 and said transparent casing 31 .

A plurality of outwardly extending protrusions or feet 33 are provided on the housing half 34 . When the device is mounted on a surface (also not shown), the feet ensure that a permanent gap is formed between the housing 31 and the surface (also not shown). The gap improves heat exchange between the device and the environment.

The feet 28 extend beyond the housing half 34 in order to allow the device 20 to be mounted on a printed circuit board (not shown) in known manner. The feet 33 ensure a permanent gap between the device and the printed circuit board to facilitate air circulation between the transformer and the circuit board, thereby improving heat dissipation from the transformer.

It is believed that due to the transparent bobbin 22, the windings 24, 26 are not surrounded by insulating tape and the thin transparent casing 38 is provided, the heat generated by the transformer can be transferred outwards more than in the above-mentioned prior art Outward transmission is more efficient in the transformer in .

The arrangement forms holes 40 in the ear regions 42 , 44 of the bobbin 22 and housing half 34 , respectively. These holes are used to mount the transponder on the base plate 46, for example by means of bolts 48 or screws and nuts, said holes being easily accessible from where the central axes of said holes coincide.

Thus, the simple device according to the invention is suitable for so-called printed circuit board and chassis mounts.

A power supply unit 50 according to the invention is shown in FIGS. 4 and 5 . The power supply unit 50 includes a transparent or translucent box-shaped cover 52 suitable for power supply circuitry 54 including a transformer 56 . The shield 52 facilitates the transfer of heat generated by the electrical circuitry.

The enclosure includes a plurality of plugs 58 (two or three) for cooperating with conventional socket means (not shown) of the mains network. In the bottom plate 52.1 of the housing there is a cavity 60 suitable for a replaceable fuse 62 connected in the primary or secondary circuit of the transformer. The cavity is opened and closed by a removable cover 64 .

The shroud defines a first opening that provides access to a first pair of DC outputs 66 of the power supply unit. A second pair of outputs 68 in parallel with the first pair is also accessible through the shroud.

A block diagram of the power supply unit is shown in FIG. 6 . The aforementioned plug is numbered 58, and the plug 58 is connected to a protection circuit system 70 and the primary winding 72 of the transformer, wherein the protection circuit system 70 includes a discharge protection circuit system. The secondary winding 74 of the transformer is connected to a voltage regulation circuit 76 connected to the outputs 66 and 68 . The fuse 62 may be connected to the primary and/or secondary circuit of the transformer.

It will be appreciated that many changes in detail may be made in the apparatus and method according to the invention without departing from the scope and spirit of the appended claims.

Claims (10)

1. An electrical device (20), comprising a transformer (30) and a permanent translucent or transparent electrical insulation housing (31), so that the heat generated by the transformer is passed outwards through the cover, characterized in that The housing (31) has the same shape as the transformer (30). 2. Device according to claim 1, characterized in that said casing (31) is transparent. 3. The device according to claim 1, characterized in that said transformer comprises a transparent bobbin (22) on which a transformer core (23) and a transformer winding are mounted. 4. Device according to any one of claims 1-3, characterized in that the housing forms a thin shell (38). 5. The device according to claim 4, characterized in that said casing (38) comprises a transparent outer casing (31) of rigid material and a layer of transparent filling material filled between said casing and said transformer (37). 6. Apparatus according to claim 5, characterized in that said housing comprises first and second housing halves (32, 34) which are fitted together to form said housing. 7. A device according to claim 4, characterized in that said housing includes outwardly extending protrusions (33) so as to form a gap between said housing and a surface on which said device is mounted in use. 8. A method of forming an electrical device, said method comprising the steps of: - providing a transformer (30); and - permanently enclosing said transformer in a transparent or translucent electrically insulating housing (31), said housing (31) having the same shape as said transformer (30), enabling use The electrically insulated housing described in dissipates the heat generated by the transformer to the outside. 9. A method according to claim 8, characterized in that said housing forms a thin shell. 10. Method according to claim 9, characterized in that said transformer is placed in such a way: by installing said transformer (30) in said housing such that the entire outer surface of said transformer (30) and said housing A small gap is formed between (31); the transparent electrical insulating material (37) is filled in the gap, so that the transformer is positioned.

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