US1161989A - Insulating fabric. - Google Patents

Description

C. E. SKINNER.

INSULATING FABRIC.

APPLICATION FILED MAY Is. 1910.

1,161,989'l Patented Nov. 30, 1915.

wIINEssEs: INVENTOR l 4 l l f ATTORNEY UNITED STATES PATENT OFFICE.

CHARLES E. SKINNER, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR T0 WESTING- HOUSE ELEC-TRIO AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYL- VANIA.

INSULATINC- FABRIC.

Specication of Letters Patent.

Patented Nov. 30, 1915.

Original application iled October 7, 1908, Serial No. 456,609. lDivided and this application led May 16, 1908. .Serial No. 561,746.

To all ywhom t may concern.'

Be it known that I, CHARLESE. 'SKINNER, a citizen of the United States, and a resident of Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Insulating Fabrics, of which the following is a specification, this application being a division of m application, Serial No. 456,609, filed Octo er 1908. l

My invention relates to insulating fabrics for electrical apparatus and it has for its object to provide a fire-proof fabric which shall be adapted for use at relatively high temperature.

Field coils for dynamo-electric machines have heretofore been constructed by winding copper stra or ribbon into a rectangular helix, and, since the voltage between turns in coils of this character is relatively low, strips of insulating material have usually been inserted between the turns of the helix in pref- -erence to Wrapping the conductor with insulating tape or completely covering it by other means, in order to improve the ventilation of the winding.

According to my present invention, I provide a fabric composed of metal foil or very thin metal ribbon which hasV been so treated as to produce a hard film or coating of insulation on its surface. Since foil of approximately one-thousandth of an inch in thickness may be employed, the space occupied by the insulation is relatively small while, at the same time, the coil, or other electrical conductor with which it is used, is rendered fire-proof and capable of operation at high temperatures. The coated metal foil (preferably aluminum) may be used in combination with sheet mica, the foil serving to hold the mica sheets or flakes in position, thereby avoiding the necessity for paper or other carbonizable fabric, such as is usually employed.

Figure 1 of the accompanying drawings, is a sectional view, on a large scale, of a sheet or strip of metal foil which has been treated to produce the insulating fabric of my invention. Fig. 2 is a similar View of an insulating fabric which is built up of several layers of the kind shown in Fig. 1 and separated by sheet mica or other similar insulating material. Fig.- 3 is a perspective view of an insulating ribbon or strip which is similar in construction to the fabric of Fig.

shown in section, 1s composed of three layers 4, 5 and 6 of coated aluminum foil separated by layers 7 and 8 of mica or other similar insulating material. By using the mica flakes, in combination with the aluminum foil, the insulating fabric is adapted to insulate for relatively high voltages While, at the same time, no combustible material is introduced.

I prefer to emplo" strips of aluminum foil of substantially one-thousandth of an inch in thickness in order that a minimum amount of space ,may be occupied by the insulation when used in connection With coils and other current-conducting parts.

An especially good insulating film may be obtained by passing the strip of aluminum through a bath of ammonium borate, or some other suitable liquid, and, at the same time, passing electric current through the conductor and the bath. By this means, an aluminum oxid film, which is relatively hard and is not readily destroyed by heat, is produced. Either one or both of the surfaces of the metal foil may be covered with the insulating film.

My invention is not limited to use with any particular form or type of electric apparatus but is capable of application for all insulating purposes where sheet insulating material c'an be employed.

I claim as my invention:

1. A fire-proof material for insulating electric conductors consisting of metal foil having a heat-resisting coating of hard insulating material upon its surface.

2. A fire-proof material for insulating electric conductors consisting of aluminum foil having a heat-resisting coating of hard insulating material formed upon its surface.

3. A lire-proof insulation comprising alternate layers of metal foil having insulating coatings on their surfaces and other heatresisting insulating material.

4. A fire-proof insulating material comhaving oxid insulating coatings on their surfaces and mica flakes, the mica flakes held being in position by the foil.

In testimony whereof, I have hereunto subscribed my name this 3rd' day of May,

5. A fireproof insulating material com- 1910. v prising non-combustible sheet material coated CHARLES E. SKINNER. with non-combustible insulating material. Witnesses:

A ireproof insulating material comprising oxidized aluminum fm1.

F. E. OLIVER, B. B. HINES.

It is hereby certified that in Letters Patent No. 1,161,989, granted November 30,

1915, upon the application of Charles E. Skinner, of Wilkinsburg, Pennsylvania,

for an improvement in Insulating Fabrics, errors appear in the printed specification requiring correction as follows: Page 1, line 15, for the word temperature read temperatures; page 2, lines 1-2, for the Words held being read beingbeld; and

that the said Lettersl Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Ofce.

Signed and sealed this 18th day of January, A. D., 1916.

[SEAL] J'. T. NEWTON,

Acting Commissioner Q7" Patents. Cl. 173-320.

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