US2458957A - Temperature compensator for electrical regulators - Google Patents

Description

W. G. NEILD Jan. 11, 1949.

TEMPERATURE COMPENSATOR FOR ELECTRICAL REGULATORS Filed March 20, 1945 ATTORNEY f Patented Jan. 11, 1949 UNITED STATES PATENT OFFICE TEMPERATURE COMPENSATOB FOR ELECTRICAL REGULATORS 4 Claims. 1

The present invention relates to electrical regulating apparatus and more particularly to a novel temperature compensating means for such apparatus, together with novel means for adjustingthe magnetic characteristics of the apparatus.

An object of the invention is to provide novel means acting directly upon a core of an electromagnetic winding for compensating for variances in the electromagnetic characteristics of the device due to changes in temperature.

Another object of the invention is to provide novel means for adjusting the core of the elec tromagnetic winding for varying the electromagnetic eflect' upon the armature operated thereby.

Another object of the invention is to provide novel manually adjustable means whereby the relationship between the spring and electromagnetic forces may be varied so as to impart a drooping or rising controlled current or voltage characteristic to the regulator.

These and other objects and features of the invention are pointed out in the following description interms of the embodiment thereof which is shown in the accompanying drawings. It is to be understood, however, that the drawings are for the purpose of illustration only, and are not designed as a definition of the limits of the invention, reference being had to the appended claims for this purpose.

Figure l is a sectional View of a regulator embodying one form of the invention.

Figure 2 is a fragmentary view illustrating an adjusted portion of the core.

Figure 3 is a modified form of the invention.

Referring to the drawing of Fi ure 1, there is provided a bottom plate I on which is mounted a casing 2. The bottom plate I and easing 2 are formed of a suitable ferr c-magnetic material. Screw threadedly engaged in the bottom plate l and projecting into the casing 2 is a cylindrical iron core member 5 which cooperates with a top tapered portion 6 of the casing 2 in providing a variable leakage magnetic path.

About the core member 5 is wound the electromagnetic winding 1, preferably of a suitable copper wire. Positioned on the casing 2 is an annular member I! which is fastened to the bottom plate I by suitable screws I2, one of which is shown in the drawing.

A housing of a type such as shown in the copending application Serial No. 570,002, filed December 2'7, 1944, now Patent No. 2,427,805, is-

sued September 23, 1947, is fastened to the annular member 10 b screws it one of which is shown. in the drawing. Mounted Within the housing 20, as shown in greater detail inthe aforenoted application, is a non-conducting tube of a suitable refractory material such porcelain. The tubular member 25 carries carbon discs forming a carbon ile. A cont-actor member is positioned between one end of the carbon pile 3i! and an armature plate 36. The contactor member 35 is positioned in a cup shaped securing member 40, mounted on the armature 36. The carbon pile is connected so as to regulate a suitable electric circuit in response to energization of the electromagnetic winding 7.

The armature plate 36 is positioned at one side of a leaf spring 45. At the opposite side of the leaf spring is Positioned a second armature plate 48 and the leaf spring 45 is clamped between the armature plates 35 and 48. The leaf spring 45 may be of a type such as shown in the copending application Serial No. 570,002, filed December 27, 1944, now patent No. 2,427,805, icsued. September 23, 1947, or may be of a type such as shown in the copending application Serial No. 583,812, filed March 20, 1945, now Patent No. 2,427,806, issued September 23, 1947, wherein the force exerted by the leaf spring on the carbon pile 30 is varied so as to eiiect basic correspondence with varying magnet pull results. The lat ter arrangement is fully described and claimed in the aforenoted applications and therefore a detail description of the same is not deemed necessary in the present application.

The cylindrical core member 5 is formed of a suitable iron bearing material and may be adjustably screwed into the bottom plate 5. The outer end 8 of the member 5 may be formed of a hexagonal shape whereby the same is adapted for convenient adjustment.

Positioned within the cylindrical core member 5 is a field-adjusting male screw member 50 pref erably formed of a stainless steel. The screw member 50 is engaged in screw threads formed within the cylindrical member 5 so that by turning the. screw member 50 the same may be adjusted' axially within the cylindrical member 5. The outer end 5| of the screw member 5 3 may have a hexagonal shape, whereby the same is readily adapted for convenient adjustment.

The screw member 5!! has formed therein an axially extending bore 56 in which there is positioned' an aluminum rod 60 which has the low end portion secured in the screw member 50.

The upper end portion 66 of the aluminum red I is secured in an iron core member 68 having a bore portion 69 in which is likewise positioned the aluminum rod 60.

Upon an increase in temperature the aluminum rod 68 expands in relation to the iron cylinder so as to push the iron core member 68 upward so as to decrease the airgap between it and the armature plate 48 and thereby increase the electromagnetic pull on the armature plate 48.

As the electromagnetic winding 7 tends to heat up the resistance of the copper wire forming this winding tends to increase and, with constant current or voltages, the ampere turns fall ofi so that the downward pull of the electromagnet 1 on the armature plate 48 would normally tend to decrease, whereupon if uncompensated the leaf spring 45 would tend to move the contact 35 towards the carbon pile 30 and further compressing the same so as to decrease the resistance thereof.

However, with the novel aluminum rod 60 provided herein it will be seen that the changes in the length of the same will cause a variance in the magnetic forces acting on the armature plate 48 so as to compensate for changes in the resistance of the copper wire of the electromagnetic winding 1.

Moreover, as shown in Figure 2, the magnetic characteristics of the device may be altered as required to take up the slack of manufacturing tolerances in the leaf spring 45' and to vary the magnetic characteristics of the device in relation to the spring force. This may be done by varying the relative positions of the cylindrical iron core 5 and inner iron core 68 in relation to the tapered top plate 6. Thus by properly adjusting the relationship of the cores 5 and 68, the magnetic leakage between the cores and taperedotop plate 6 may be varied without varying the air gap between the core 68 and armature plate 58. Similarly the magnetic saturation of the core 58 may be varied without changing the air gap between'the core 58 and the armature plate 48.

The advantage of the latter arrangement over that of a core which may be adjusted bodily in relation to the armature lies, of course, in the fact that the air gap between the inner core 63 and armature plate 48 may be retained constant, while merely the leakage and saturation of the iron core 58 is changed through adjustment of the outer cylinder core 5.

In a carbon pile regulator of the type described, if the combined forces exerted by the spring 45 and carbon pile 35 decreases at a rate less than that of the counteracting forces exerted by the electromagnet l as the air gap between the armature 48 and core 68 increases, there will be a resultant rise in the value of the current or voltage controlled by the carbon pile resistance 30 in response to the electromagnet 1.

Further, if the combined forces exerted by the spring 45 and carbon pile decreases at a rate greater than that of the counter-acting forces exerted by the electromagnet as the air gap between the armature 48 and core 68 increases there will be a resultant droop in the value of the current or voltage controlled by the carbon pile resistance 30 in response to the electromagnet I.

The operating characteristic then, of the electromagnet i may be adjusted in relation to the combined forces of the spring 45 and carbon pile 4 and saturation of the core 68 through the adjustment of the cores 5 and 68 in relation to the tapered portion 6 of the casing 2, as previously described.

In Figure 3, there is shown a modified form of the invention, in which like numerals indicate like parts to those shown in Figure 1. In the latter form of the invention the end 10 of the core 68 is formed with a tapered portion H which is adapted to fit in a seat, portion formed at the inner end of the cylindrical member 5.

It will be seen moreover, that in the latter arrangement the face of the core 68 through which magnetic lines of force act upon the armature 30 so as to provide as desired, either a drooping or a rising characteristic to the regulator. This may be accomplished by adjusting the leakage plate 48 remains constant and that adjustment of the core 88 in response to the temperature change effects the air gap between the armature and core 68, the magnetic leakage through the casing 2, and the saturation of the core 68 as previously explained. Likewise manual adjustment of the cylindrical core 5 will effect a similar result.

Although only two embodiments of the invention have been illustrated and described, various changes in the form and relative arrangements of the parts, which will now appear to those skilled in the art, may be made without departing from the scope of the invention. Reference is. therefore, to be had to th appended claims for a definition of the limits of the invention.

What is claimed is:

1. An electrical regulator comprising a variable resistance element, an electromagnetic winding, a spring biased armature operated by said electromagnetic winding for regulating said variable resistance element, a cylindrical core, means for adjustably mounting the cylindrical core relative to said electromagnetic winding, said cylindrical core formed of an iron bearing material, a second core formed of an iron bearing material slidably mounted in said cylindrical core and positioned in spaced relation to said armature, a member adjustably mounted at the outer end of said cylindrical core, a rod positioned between said member and said second core and formed of a material having such a greater temperature coefiicient of expansion than that of the material of the cylindrical core that the elongation of said rod causes the position of said second core to vary with temperature, and said cylindrical core adjustable for changing the magnetic leakage of said second core to vary the control characteristic of the regulator independently of the air gap between said second core and the armature.

2. An electrical regulator comprising a variable resistance element, an electromagnetic winding, a spring biased armature operated by said electromagnetic winding for regulating said variable resistance element, a cylindrical core projecting into said electromagnetic winding and formed of an iron bearing material, means for adjustably mounting the cylindrical core relative to said electromagnetic winding, a second core formed of an iron bearing material slidably mounted in said cylindrical core and positioned in spaced relation to said armature, said cylindrical core having a tapered seat portion formed at the inner end thereof, said second core having a tapered portion formed at an end adjacent said seat portion and adapted to fit within said tapered seat portion, a member screw threadedly engaged at the outer end of said cylindrical core, a rod positioned between said member and said second core and formed of a material having such a greater coefiicient of expansion than that of the cylindrical core that the elongation of the rod causes the position of said second core to vary with temperature, and said cylindrical core adjustable for changing the magnetic leakage of said second core to vary the control characteristic of the regulator independently of the air gap between said second core and the armature.

3. An electrical regulator comprising a variable resistance element, an electromagnetic winding, a spring biased armature operated by said electromagnetic winding for regulating said variable resistance element, a cylindrical core projecting into said electromagnetic winding and formed of an iron bearing material, a second core formed of an iron bearingmaterial slidably mounted in said cylindrical core and positioned in spaced relation to said armature, a member formed of a ferro magnetic material and forming part of a magnetic circuit, said member having a portion positioned in spaced relation to the inner end of said cylindrical core and said second core, means for adjustably positioning the relationship of one of said cores to said inwardly projecting portion separately from the other, so as to vary independently of the air gap between the other of said cores and said armature the effective magnetic force acting upon said armature by varying the magnetic leakage between the member and said cores.

4. An electrical regulator comprising a variable resistance element, an electromagnetic winding, a spring biased armature operated by said electromagnetic winding for regulating said variable resistance element, a cylindrical core projecting into said electromagnetic winding and formed of an iron bearing material, a second core formed of an iron bearing material slidably mounted in said cylindrical core and positioned in spaced relation to said armature, a casing for said electromagnetic winding formed of a ferro magnetic material and having a tapered orifice, the inner end of said cylindrical core and second core projecting into said tapered orifice, manually operable means for adjusting the cylindrical core in relation to said tapered orifice so as to vary the efiective magnetic force acting upon said armature, and manually operable means for adjusting said second core in relation to said cylindrical core so as to maintain the air gap between said second core and said armature substantially constant upon adjustment of said cylindrical cor-e in relation to said tapered orifice to effect initial fine adjustment of the magnetic leakage between the cores and easing without varying the air gap between said second core and armature.

WILLIAM G. NEILD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,425,858 Hunt Aug. 15, 1922 2,336,523 Allen Dec. 14, 1943 2,354,542 Rady July 25, 1945 2,387,127 Dodd Oct. 16, 1945

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