US1491386A - Pole shader - Google Patents

Description

' April 22 ,-19z4. 1,491,386

7 J. B. FORD POLE SHADER Filed June 22. 1921 lh\/entor". I John BF'or'd,

His Attorney.

Patented Apr. 22, 1924.

, UNITED STATES I v "1,491,386 PATENT OFFICE.

. JOHN. B..FORD, OF SCHENEGTADY, NEW YORK, ASSIGNOR T GENERAL TELEC'IFRIIC COMPANY, A CORPORATION OF NEW YORK.

POLE snaman.

Application filed June 22, 1921. Serial No. 479,600.

To all whom it may concern:-

Be it known that 1, JOHN B. FORD, a

citizen of the United States, residing at Schenectady, county of Schenectady, State 6 of New York, have invented certain new and useful Improvements in Pole Shaders, of which the following is a specification. It is common practice to. provide pole shaders of copper or other good conducting 10 material for the purposeof setting up in a magnetic structure for alternating current apparatus, a magnetic flux which is displaced in phase from the main flux through the structure so as to thereby have the flux in the structure maintained while the main flux is passing through the zero value. For example, such pole shaders have been used in alternating current switches to prevent chattering by setting 'up a maintaining flux displaced in phase from the main flux, the maintaining flux serving to magnetically hold the movable magnetic member of the switch during the time while the alternations of the main flux pass through the zero value. Such pole shaders have a disadvantage in that a substantial portion of the pole faceof the magnetic structure must be cut away in order to accommodate the pole shader, and the effective area of the pole face is thereby materially reduced since copper is nonmagnetic.

One of the objects of my invention is to provide a pole shader which is not only electrically conductive, but also has magnetic-properties, so that the entire area of the pole face in which the pole shader is embedded shall be effective in carrying the lines of magnetic flux.

In order for the pole shader to have the greatest effect in setting up a displaced magnetic flux, the resistance of the pole shader should be approximately equal to the reactance thereof, and I have found that steel has the desired properties, although my invention is not necessarily limited to pole shaders of steel.

The magnetic structure of an alternating current device is ordinarily made up of laminations of magnetic material, and some means must be provided for holding the laminations together. Iron bolts or pins are customarily used for that purpose, since the iron bolts or pins are also magnetic.

Another of the objects of my invention isto provide a pole shader which is held in place by the means for holding the laminations of the magnetic structure together. The pole shader is thereby securely held in place and becomes for all practical purposes an integral part of the magnetic structure.

For a better understandingof my invention, reference is had to the accompanying drawing which shows an embodiment of my invention for purposes of illustration, and in which Fig. 1 showsthe operating electromagnet of an alternating current electromagnetic switch with two pole shaders incorporated therein, in accordance with my invention; Fig. 2.-is a perspective detail the pole I 13 mounted on one of the poles of the magnetic structure. ing apart of the magnetic structure is a magnetic movable element, an armature 14, which is supported in a cradle 15 so. that the armature will accurately align itself with the pole faces of the magnetic structure. The cradle support 15 is pivotally mounted in a support 16 and is adapted to "operate a shaft 17 to which switch mechanism or other devices to be operated by the electromagnet are connected. While I have shown a pole shader on each pole of the magnetic structure, my invention is not necessarily limited thereto, since a single pole shader will have beneficial results in maintaining the armature of the electromagnet attracted duringthe time that the ,main flux of the electromagnet is passing through the zero "value. For switches in which a cradled armature or other movable magnetic member is provided for cooperation with a U-shaped magnetic structure, I find it advisable, although not necessary, to employv a pole shader embeddedin the end of each leg of the magnetic structure.

' The pole shader is embedded in the laminated magnetic structure so as to be at right Associated with and formnetic and electric conducting material, and

the resistance thereof is predetermined so as to be substantially equal to the reactance thereof. I have found that steel has the desirable quality of not only being magnetic, but also has a sufiiciently high resistance so that the reactance of the pole shader will be substantially equal to the resistance.

' This pole shader will set up a magnetic flux which is angularly displaced with respect to the main flux set up in the magnetic structure due to the energization of the winding 13 so as to magnetically hold the armature 14 during the time that the main flux is passing through the zero value. By reason of the fact that the pole shader has a resistance which is substantially equal to the reactance thereof, the pole shader will have the maximum effect in setting up a suitably displaced magnetic maintaining flux.

The pole shader is provided with angularly disposed ears 18 and 19 which embrace the sides of the pole and provide means for holding the pole shader in place in the magnetic structure. Each of the ears 18 and "19 is provided with an aperture through which the iron bolt or pin 20 is adapted to pass, so as to hold the pole shader in position in the magnetic structure, and also for the purpose of holding the laminations of the magnetic structure together. It will be seen that the effective area of the pole face of the magnetic structure has not been lessened in any way because of the provision of the pole shader. That is because of the fact that the pole shader is of magnetic material. It is also to be noted that the pole shader can be put in place on the pole of the magnetic structure and then filed so as to be exactly flush with the surface formed by the ends of the laminations of the magnetic structure. An accurate alignment of the armature 14 with respect to the surface of the magnetic structure is thereby made possible. The pole shader when in position on the pole of the magnetic structure becomes substantially an intlegral part of the magnetic structure.

e pole shader isvery effective in preventing the noise or chattering which occurs in alternating current dew ices. This is due to the fact that the pole shader sets u a very substantial dephased magnetic hol mg flux and also from the fact that the ole shader and the laminations are securely eld to ether by the rivet or bolt 20.

n Fig. 4, I have shownan alternative netic pole and the flux set up method of mounting the pole shader in position, and it will be seen that in this case the pole shader does not have the same proportion of the total of the pole surface included within the pole shader as in the case of the pole shaders of the 'other fi res. The reactanceof the. pole shader in ig. 4. will necessarily be less than the reactance of the'pole shader as shown in Fig. 2. The resistance, however, will be the same and it will be understood from this by those skilled in the art the manner in which the pole shader maybe adjusted in position so as to have the desired reactance. It will be understood by those skilled in the art the manner in which the resistance of the pole shader may be varied. The adjustment of the proper reactance for the pole'shader will be determined by testing the effort required to pull the armature 14 away from the pole pieces.

The ears 18 and 19 of the pole shader have a distinct effect in setting up the dephased magnetic flux. That is because of the fact that these ears, together with the pin 20, cause eddy currents to be set u in the m currents is also dephased from t e main flux and thus assist dephased flux set up by the main flat part of t e pole shader.

In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention, together with the apparatus wh1ch I now consider to represent the best embodiment thereof, but I desire to have it understood that the apparatus shown is only illustrative and that the invention can be carried out by other means.

What Iclaim as new and desire to secure by Letters Patent of the United States, is,-

1. In combination, a magnetic structure having a winding thereon and a pole shader in the pole face of said structure, the said pole shader having a resistance which is substantially equal to the reactance thereof.

Y 2. A pole shader having a main part consisting of aband having ears on the ends thereof angularly disposed to the said main part for embracing the sides of a pole of magnetic material to hold the pole shader in position on the pole.

3. In combination, a magnetic structure, and a pole shader thereon having a. main part consisting of a band and an ear on each end thereof angularly disposed to the said main part for embracing the sides of the pole of the said magnetic structure, the said ears having apertures therein, and a pin of flux which assists the de based flux of the said main part of the poo shader.

these ed y osition on the 4. The combination in an electromagnetic device of a magnetic structure comprising a core and a movable member arranged to be magnetically attracted into engagement with a ole surface of the said core, and a steel po e shader embedded in the said structure and forming a part of the engaging surfaces of the said member and core, the said pole shader having a resistance which is substantially equal to the reactance thereof.

5. The combination in an electromagnetic device of a. laminated magnetic structure, a.

steel pole shader, having a resistance substan-t tially equal to the reactance thereof, embedded 1n and surrounding a portion of the pole surface of said structure, the said pole shader having angularly disposed ears on the ends thereof which embrace the sides of thepole, the said ears having a rtures therein, and a bolt which passes t rough the said apertures for holding the pole shader in position on the said pole and for holding the laminations of said structure together. In witness whereof, I have hereunto set my hand this 21st day of June, 1921.

JOHN B. FORD.

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