US1382905A - Cooling means for electric metal-working transformers - Google Patents

Description

. J. H. GRAVELL. COOLING MEANS FOR ELEQTRlQ-METAL WORKING TRANSFORMERS.-

APPLICATION men on. 4. 1s19.

- 1,3 2,905. r mnmunezs, 1921.

Jams 19 rffvel/ v 3511/! Queen W43 weldin UNITED STATES PATENT OFFICE.

JAMES H. GBAVELL, OF ELKINS PARK, PENNSYLVANIA, ASSIGN'OB T0 THOMS ON ELECTRIC WELDING COMPANY, OF BOSTON, MASSACHUSETTS, A. CORPORA- v TION OF MASSACHUSETTS.

COQLING FOR ELECTRIC METAL-WORKING TRANSFORMERS.

Specification of Letters Patent. Patented June 28, 1921.

Application filed October 4, 1919. Serial No. 328,544.

To all whom it may concern Be it known that 1, JAMES H. GnAvnLL, a citizen of the United States, and a resident of Elkins Park, in the county of Montgomery and State of Pennsylvania, have invented certain new and useful Improvements in Cooling Means for Electric Metal-Working Transformers, of which the following is a specification.

This invention relates to the cooling electric coils of transformers for electric metal working apparatus or of other apparatus. The invention is herein described as applied to the welding transformer although it may be used in the coils of transformers for other metal working operations or of otherthe cooloperation of the coil and the transformer or other apparatus of which it forms a part and to reduce the space occupied thereby, thus reducing the cost of manufacture, the weight and its self inductance, while at the same time permitting the use of a conducting fluid and a cooling medium without objectionable difference of potential existing at the ends of the fluid stream.

It is well known in the design of the transformer that the resistance of the primary windings in itself is of little importance and may be varied over a long range without affecting the practical current output. It is, however, of high importance that the apparatus remain ieasona ly cold so that the insulation is not injured and it therefore becomes necessary to make the primary conductors of large cross-section not to lessen the resistance but to reduce their heating.

According to the present invention the primary winding can have any desired crosssection on a maximum lcsistance and no consideration of the radiating surface is necessary, while moreover the presence of the conducting cooling medium in contact with the coil introduces no difficulty arising from a difference of potential between the inlet and outlet ends of the stream of cooling fluid.

In order to accomplish the objects of this core A. The source of current passed through the tubular primary or other coil, thus maintaining it at a relatively low temperature, but the coil is so constructed and the fluid is so circulated through the same that the electrical potential of the fluid at the two ends of the tube will be the same. Any other cooling medium such as alcohol or air might be passed through the conductors but I prefer to use water for obvious reasons, such as cheapness, ease of handling, &c.

The invention consists in the construction of coil and manner of circulating the cooling fluid therethrough as hereinafter more particularly described and then set forth in the claims.

In the accompanying drawings the invention is diagrammatically illustrated to show the principle thereof in the simplest manner, it being understood that the construction shown is for the purpose of illustration only.

a The drawing shows in elevation a coil so constructed that my present invention may be carried into efiect.

With a single tubular coil in which'the coolin medium and the current are circulated in one direction only there is a difference of potential between the inflowing water and the outflowing water that in some cases might cause serious trouble due to short 'circuiting the current, particularly in the case when the coilis a primary coil.

To overcome this disadvantage, I provide the construction as shown in the drawings. In this'case the conductor consists of two tubes B and B wound in electrical arallel on the is connected so as to branch through the two coils flowing from theline terminal E to the two tubular terminals B and B then through the two coils to the points D and D and to the other line terminal E The two tubular coil ends D and D" are connected together as at D so that the cooling medium can flow from one to the other as shown, making the two coils one continuous tube or pipe for the conduct ends F and F It will be observed that although the electric current flows in parallel through the two windings, the cooling medium flows through the two windings in serles. V

When my invention is employed with a transformer the primary 0011 may be of small dimensions without danger. of overheating. Owing to the smallness of the primary, the secondary shown at G may be placed much nearer to the core than in the old construction of the primary which, in case a continuous or closed core is used, enables the total length of core to be reduced. This has the advantage of reducing the self inductance of the transformer and reducing the eddy current and hysteresis losses. These factors work tothe great advantage of current output of the secondary which is so desirable in metal working transformers.

The means of insulating the various convolutions of the primary is not shown, as this is well understood in the art.

The invention claimed is 1. An electric coil having two windings of hollow tubing connected to permit the cooling medium to flow through them in series and having electrical connections to cause electric current to flow through them in parallel.

2. An electric conductor made of two sections or lengths of hollow tubing connected to permit the cooling medium to flow through them in series and having electrical connections to cause electric current to flow through them in parallel.

3. A transformer having two windings of hollow tubing connected to permit the cooling medium to flow through them in series and having electrical connections to cause electric current to flow through them in parallel.

Signed at New York, in the county of New York and State of New York, this 1st day of October, A. D. 1919.

JAMES H. GRAVELL.

Witnesses:

F. B. TOWNSEND, IRENE LEFKowITz.

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