US905554A - Insulated conductor. - Google Patents

Description

I J. I. MITCHELL. INSULATEDOOHDUGTOR. APPLICATION FILED 3331214, 1903.

Patented Dec. 1,1908,

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JOSEPH I. MITCHELL, OF SCHENECTADY, NEW YORK. ASSIGNOR .TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

INSULATED CONDUCTOR.

Specification of Letters Patent.

Patented Dec. 1, 1908.

Application filed September 14, 1993- Serial No. 173,07.

useful Improvements in Insulated Conductors, of which the following is a specification.

The use of conductors in the form of rib-.

bone or strips as distinguished from Wires or rods has been found highly advantageous in various linesof electrical a paratus. For instance these strips or 'ri' bons are frequently bent edgewise to -form currentcarrying coils or windings for transformers, field magnets or the like. Some difficulty has heretofore been experienced in insulating such conductors. These difficulties have been due in art to the severe mechanical strains to w ich the insulation is subject when the insulated conductor is bent as in the formation of edgewise-wound coils. It has also been found that small spines or slivers of the conducting material sometimes project from the conductor and these spines or slivers occasionally penetrate the insulation and establish contact between layers of the same coil 01' with other conductin terial in proximit to the conductor. l have discovered that t ese difiiculties can be done away with by the employment of a strip or ribbon of strong paper or similar insulating material secured at one or both sides of the strip of conducting material. In carrying out my invention I place the strips of conducting material and insulation with their edges parallel and incase them in a single layer of cotton, silk or the like, which is woven or braided about the conducting and insulating strips. With this construction the paper or similar insulating material is held firmly in place by the woven or braided jacket and is not unduly distorted by the coil-forming or similar operations. Moreover the stron paper or the like is not penetratedby the me spines projecting from the conductor and hence the dii'liculty from this cause is avoided. The woven jacket also adds to the insulation.

For a better understanding of my invention reference may be had to the accom-- panying drawings in which I have illustrated embodiments of my invention.

Of the drawings E' ure 1 is a perspective view illustrating coil formed from an edge Wise-wound insulated conductor constructed 5 in accordance with my invention; Fig. 2 is an enlarged view showing an insulated conductor consisting of one layer of conducting material and one layer of insulating material; Eig'. 3 is a similar view showing a conductor provided with a layer of insulating material at each side of the strip or ribbon of conducting material; and Fig. 4 illustrates a modified arrangement of the insulating layer.

Referring to Fig. 2 or the drawings, a ribcopper is shown as placed side by side with a layer or strip 2 of insulating material such as paper, hard fiber, sheet mica, compositions containing one or more of these materials or the like. A textile jacket 3 of cotton, silk. or the like is woven or braided about the conducting strip 1 and the strip of insulating material 2. In practice I prefer to assemble the conducting strip and the insulating strip and to surround them with the woven or braided jacket simultaneously though it is not essential that this be done.

"When the insulated conductor is Wound into a coil in the manner shown in Fig. 1, it will be seen that each turn of the conducting strip is se arated from adjacent turns by one layer of t e paper or similar material 2 and two layers of the woven fabric 3.

layer 2 of paper or the like is placed at each side of the conducting strip, and the three layers are then inclosed in a single jacket. It will be readily understood that in a coil constructed out of an insulated conductor formed in the manner described each turn of the conducting material would be separated by two layers of the paper or the like as well as by two layers of the woven fabric.

It will of coursebe obvious that more than one thickness of the paper or the like and more than one thickness of the conducting material may be employed to form the layers 2 and 1 respectively. As before stated, the exact compositions of the insulating material out of which the layer orlayers 2 are formed is immaterial. I have obtained very good results in some instances from the use of an insulation composed of a strip of paper upon which scales or pieces of mica are secured by glue or the like. A coil formed out of sucli'an insulated conductorzpossesse' the In the construction shown in Fig. 3 a

bon or strip 1 of conducting material such as further advantage that it is practically fireproof since the mica which forms the major ortion of the insulation is practically unaftected by fire.

Nhile ordinarily it is sufl'icient to employ strips of paper or the like of a width equal to that of the conducting strips, as shown in Figs. 1, 2 and 3, it may in some instances be desirable to employ strips of insulating matel; rial Wider than the strip of conducting material. in such cases the insulating material may, if desired, be turned up at the edges so that the paper or a similar material forms a trough in which the conducting strip is placed, as shown in Fig. l \Vhcn the strips of paper or the like are not greater in width than the strips of conducting material, the edges of the conducting strips are of course protected only by the woven fabric. This, however, is sufiicient for many purposes.

\Vhat I claim as new, and desire to secure by Letters Patent of the United States, is, A conductor adapted for use in making edgewise-wound COIlS consisting of a flat strip or ribbon of conducting material, a flat strip or ribbon of insulating material lying against one side of the strip of conducting material, and a textile jacket fitting said assembled strips so as to hold them'against relative displacement In Witness whereof I have liereuntojset my hand this 12th day of September, 1903.

JOSEPH .l. MITCHELL. Witnesses:

BENJAum B. HULL. HELEN ()RFmw.

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