US1230610A - High-potential insulator. - Google Patents

Description

S. S. SONNEBOHN.

HIGH PTENTIAL INSULATR.

APPLICATION FILED DEC.9, i915- 1,230,610. Patentedlune 19, 1917,

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SOL. `S. SONNEBORN, OF BROOKLYN, NEW YORK.

HIGH-POTENTIAL INSULATOR.

T0 all whom t may concern:

Be it known that I, SOL. S. SoNNEoRN, a citizen of the United States, and a resident of Brooklyn,`countyof Kings, and State of New York, have invented certain new and useful Improvements in High-Potential Insulators, set forth in the following specification.

This invention relates to high-potential insulators of the condenser type, employed as bushings for insulating transformer leads and the like from what is usually a grounded, perforated barrier of conducting material through which the conducting lead must emerge and from which it must be insulated.

The object of the invention is to form an insulator of as simple, compact and economical construction as possible, and which provides protective features against high-frequency, high-potential oscillations, due to abnormal line surges as well as embodying an efficient design for the normal voltages which it is expected to sustain. v

To these ends an important feature of the invention is to provide for relief without danger of puncture from abnormal stress produced by high-frequency oscillations, while, at the same time, employing features such as dielectric configuration conforming to the flow lines of dielectric stress between terminals, to the end that the full dielectric value of the air may be employed. The above and more detailed objects of the invention will more fully be understood by reference to the embodiment of the invention described for illustrative purposes in the following specification and shown in the accompanying drawings, which form a part hereof, in which like characters designate corresponding parts in the figures and in which Figure 1 is a sectional elevation through an illustrative embodiment and Fig. 2 is a bottom plan of a modified sheath skirt.

A indicates one embodiment illustrating the practice of my invention in the form of `a highpotential insulating bushing of the type adapted to pass through a barrier of,

conducting, usually grounded, metal such as the transformer casing B. In this type of insulator the maximum stress occurs between the lead 1 and the casing 2. In practicing my invention I contemplate the useful employment of the insuating fluid 2, which is the oil customarily filling a transformer case.

Specification of Letters Patent. Patented Jung 19, 191W.

Application filed December 9, 1916. Serial No. 135,922.

The insulator illustrated in Fig. 1 co1n prises a molded body 3 of suitable insulating material, which may be molded in thc plastic state, afterward to harden and solidify. In its finished form all the parts shown in Fig. 1 may be considered in their finished embodiment as cylindrical, such term being used in its broad sense, meaning that surfaces are surfaces of revolution. The axis of the various parts is that of the lead 1, which is shown in the form of a bolt with any suitable form of connectors such as nuts 4l.

A plurality of cylindrical metal sheaths 5 and 6, each having an outwardly flaring skirt 7 with an upturned marginal lip 8 on its outerend and an outwardly flaring skirt 9 on its inner end, are co-axially supported in a suitable mold and the plastic, insulating ma terial 3 is forced about these shells and into the mold, a suitable core forming an axial perforation for the bolt 1, which also can be molded in. The configuration of the mold should be such as to form an outwardly fiaring petticoat 410 about the outer face of each skirt 7. Cylindrical partitions 11 and 12 of insulating material of cylindrical form alternate with the cylindrical sheaths 5 and 6. The stem ofthe insulator, adapted to pass f through the barrier B, may be protected by a sheet metal bushing 13.

The contour of the outwardly Haring metal skirts 7 is such as to reduce the local dielectric stress between the conductor 1 and the casing B, and the exposed surfaces of petticoats l0 of insulating material are designed to conform as nearly as practicable with the flow lines of dielectric stress. Inasmuch as the surrounding dielectric about the outer portion of the insulator A is air, the distance from the exposed end of the lead 1 to the casing B is greater than the distance from the inner end of the lead 1 from the casing B, because it is proposed that the inner end of the lead 1 is to be immersed in oil. ThisV likewise is true for the outwardly flaring skirts 9 which may be located nearer to the casing B than can the skirts 7. The proportioning and spacing in the various parts is preferably such that a iiash-over or arc-over from the lead 1 to the casing B will never take place wholly by creepage or wholly through the air. A breakdown due to abnormal high frequency voltage will take place from one or the other or both of the out-flaring metal conducting skirts 9, immersed in the oil 2, the discharge taking place through the oil 2 to the casing B so that the dielectric medium through udii'cl the destructive discharge takes place will be self-healing and quenching, as is the nature of oil. At the same time, stressthroughout the body of the insulators solid dielectric is well distributed and relieved from intensity at any one spot by the separating sheaths serving as condenser plates. In this way the puncture potential of the bushing is increased substantially in proportion to its diameter, which is impossible Aby the use of a single layer of insulating material.

It is oi course to be understood .that .the exact number of petticoats shown in the embodiment illustrated is not a feature .oi the invention. Likewise, the invention is Lnot limited to the providing of each cylindrical metal sheath with an outwardly flaring skirt on each end, as a measure of advantage rmay be obtained by` such provisions on but lone sheath. Likewise, the number of sheaths is not limited to that shown anddescribed.

If desired, the breakdown tendency between the casing B and the 4skirts 9 maybe increased by forming the Vskirts 9 at their margins starshaped or with any kind of easily discharging points such as the starshaped skirt 90 as shown in Fig. 2.

It is also .to be understood `that such accessories as packing gaskets 2O anda finetal cap 2l may be employed. y

Vhat I claim and whatI I kdesire to secure b y United States Letters Patent is:

l. A high-potential insulating bushing of the condenser type comprising a plurality of cylindrical partitions of insulating material; and one or more coaxial cylindrical metal sheaths alternating' with said partitions, each said metal sheath being flared at each end into anoutwardly extending skirt.

2. A high-potential insulating bushing of the condenser type comprising a plurality of cylindrical partitions of insulating material 3 one or more of said partitions having at one end an outwardly `flaring petticoat; and one or more coaxial cylindrical met-al sheaths alternating with said partitions, each said metal `sheath being iiaredat each end into an outwardly extending skirt, the skirt at one end lforming a one-face-covering lor one ol said petticoats.

3. A high-potential insulating bushing ot the Vcondenser ktype comprising a vcomposite of molded insulating material and embedded metal sheaths rvforming alternating cylindrical partitions of insulation land cylindrical .metal sheaths, 4one of said metal sheaths vhaving an-outwardly flaring skirt at each end.

4L. A highpotential transformer bushing ot the condenser type comprising alternating coaxial layers of insulation and one or more metalsheaths, one oi' said metal sheaths being outwardly flared at the end ot' the insulator adapted to -be inserted into the transformer.

In witness whereof I have signed my name to this specification, .this 8th vday of December, 1916.

SOL. S. SONNEBORN.

Copies of this patent may be obtained -for ve .cents each, by addressing the Commissioner of Patents, Washington, D. C.

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