US1893251A - Voltage compensator - Google Patents

Description

Jan. 3, 1933.

J. G. SOLA VOLTAGE COMPENSATOR Filed Aug. 7. 1950 Patented vJan. 3, 1933 l UNITED STATES yPATENT oI-Flclaz JOSEPH G. SOLA, F CHICAGO, ILLINOIS, ASSIGNOR TO `SOLA CORPORATION, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS VOLTAGE COMPENSATOR Application led August 7, 1930. Serial No. 473,692.

My invention relates to voltage compensahereinafter pointed out. The preferred tors for alternating currents and it has for its means by which I have accomplished my Iobject the provision ofa new and improved several objects are illustrated in the drawform and arrangement of automatically oping and are hereinafter specifically described.

erating parts adapted when connected t0 an lThat which I believe to be new and desire 55 alternating current line to deliver a current to cover by Letters Patent is set forth in the at reduced' voltage when the voltage on the claims. line becomes too high and to deliver a current In the drawing at increased voltage when the voltageon the Fig. 1 is a diagrammatic view showing the line becomes too low; It is one of the objects preferred form of my improved voltage com- 60 of my invention to provide an improved conpensator, with certain parts broken away for struction of simple form, comprising a coil clearness of illustration. mounted upon a core which provides a `re F lgs. 2 and 3 are face views 0f the two coturn path, and comprising auxiliary core operating parts respectively of the core of l5 means providing a shunt return path of commy improved construction as shown in Fig. 5

paratively much greater reluctance than that 1; and

' of said principal return path, with means Fig. 4 is a face view of a modified form of adapted as lsaid principal return path ap-y core means. A proaches saturation by reason of an increased Referring now to Figs. 1, 2 and 3, in which voltage through said coil to have increasing corresponding parts are indicated by the same 70 effect to oppose the current through said coil reference characters, it will be seen that my and thus to cut down the voltage of the curapparatus comprises transformer means in rent delivered. 'y the form o f an autoformer made up of a pri- It is one of the objects of my invention, mary coil 10 and a secondary including the particularly in cases where it is desired to coil 10 and an auxiliary coil portion 11, said 75 operate an electrical device at the normal coils being provided with core means as herevoltage delivered by the alternating current 'after described. The primary coil 10 is conline, to provide an improved arrangement for nected between the leads 12 and 13 of an alfirst stepping up the voltage, providing thus ternating current line. A third coil 14 is confor the contingency that the line voltage may nected in series with the secondary coil of the so be too low, and then cutting down such intransformer in such relation as to opposesuch creased voltage to the necessary extent, with secondary coil, being wound in the opposite the arrangement such that when the voltage direction about the core means. Leads 15 on the line is low the effect of the voltage reand 16 are connected at opposite ends of the duct-ion means shall not be so great as that connected coils for delivery of the load curof the voltage increasing means, and that rent from the device.

when the voltage on the line is high the effect The core of my improved apparatus is all of the voltage reduction means shall be maof laminated form, the several plates of which terially greater than that of the voltage inare held together by means of clamping bars creasing means. l 17 which in turn are connected to each oth- It is one of the objects of my invention er by means of bolts 18. One of the members to provide, an arrangement by which the of the complete core means is in the form of gradual increase in the degreeof saturation a rectangular piece 19 having inwardly exr of a principal return path as the voltage intending arms 20 which are in spaced relation 4" creasesmay 'be utilized for correspondingly to each other so as to receive snugly between increasing the effect of the means 'provided them a core bar comprising a wide portion 21 for cutting down the voltage of the current at one end and a-comparatively narrow poras delivered to the load apparatus'. l tion 22 at the op osite end; In the construc- O It is another object of my invention to imtion shown the p atesmaking up the core bar o prove devices of this type in sundry details 21--22 are connected together by means of a. 100

rivet 23. The bar comprising the portions 21 and 22 is rounded at one en'd so as to have a snug fit within a groove 24 in the inner face of one of the side bars of the rectangular core part 19. At its opposite end, the `.core bar 21--22I is separated from the side of the rec tangular part 19 by an air gap as shown at 25 ing the arms 2()k and the rectangular core part 19, since the air gap at 25 causes the reluctance of the auxiliary return path through the bar portion 22 to be so much greater than the reluctance through the principal return path comprising the arms 20 that there will be a very small proportion of the lines of force passing through such auxiliary return path. As the voltage throughthe primary coil 10 increases beyond the normal so as to cause the normal return path to approach closely to saturation, the proportion of lines of force passing through the auxiliary returnl path comprising the bar portion 22 and the air gap 25 increases rapidly.

With thel voltage through the primary coil 10 at normal, the voltage through the secondary coil comprising the coil parts -10 and 11 will be found to be Very materially higher, the voltage between the leads 15 and 16, however, will be considerably lower on account of the inductance drop through the coil 14 and the counter-voltage set up in said coil 14 by the influence of the field in the auxiliary return path comprising the core bar portion 22. The strength of this counter-voltage is directly proportional to the strength of the field in the auxiliary return path, which in turn is controlled by the reluctance of such auxiliary returnpath as compared with the reluctance of the principal return'path. The size of the air gap 25, by which the reluctance of the. auxiliary return path isl controlled, is designed to be such that, when there is a normal voltage inthe coil 10, the increase in voltage in the secondary coil 10.-11 brought about'by the use of the transformer will be approximately equalled and offset so far as the voltage between the leads 15 and 16 is concerned by the decrease in the voltage between said leads 'due to th'e inductance drop through the coil 14 and the counter-voltage through said coil. Thus when there is a normal voltagebetween the line leads 12 and 13 there will beapproximately the same voltage between the load leads 15 and 16.

With the parts arranged for operation as v pass through such auxiliary return path by reason of the close approach to saturation in the principal return path. This serves very materially to increase the counter-voltage in the coil 14, with the result that a large proportion of the increase in the voltage through the coil 10 is offset and the increase in volta e between .the leads 15 and 16 is caused to e very materially less than the increase through the coil 10.

When the voltage through the coil 10 falls to a point below the normal, the strength of the field in the auxiliary return path comprising the core bar portion 22 is decreased,

and at the same time the degree `of saturation in the principal return path is lowered.

Under such conditions, the amount of the def crease in the strength of this field for a given drop in voltage is much smaller than the decrease for a` similar drop in voltage when the degree of saturation in the principal return path is comparatively higher. When the voltage through thecoil 1 drops below normal, the counter-voltage Ithrough the'coil 14 serves to reduce the voltage between the leads 15 and 16, but not sufficiently to cause such counter-voltageA and the inductance drop through the coil 14 together to balance the increase in voltage in the transformer. It follows, accordingly, that when there is such a drop in voltage in the coil 10 below normal at the same time the voltage between the leads 15 and 16 also drops below normal, but that the drop between the leads 15 and 16 is very materially less than the drop through the coil 10.

p It is thus seen that my improved apparatus serves to deliver between the leads 15 and 16 a current of a higher voltage than .that of the current flowing through the coil 10 when the voltage in such coil 10 falls'below a predeter` mined normal and to deliver between said leads 15 and 16 a current of a lower voltage than that of the current through the coil 10 when the voltage in such coil 10 rises above such predetermined normal.

In practicing my invention I havebuilt a device in accordance with the showing of Fig. 1 for -use in connection ,with an alternating current line having a normal voltage of 110 volts, such device being designed to deliver a normal load current ofthesame voltage. This device has been found to provide approximately a fifty per cent correction for variations in line voltage. That is to say, when the voltage through the coil 10 has fallen to 100 volts the voltage delivered through the leads 15 and 16 has been found to be approximately 105 volts, and when the voltage through the coil 10 has -risen to` 120 volts the voltage through said leads 15 and 16 has been found toy be approximately 115 volts.

In this machine so built in accordance with the showing of Fig. 1 and operating as above set forth, the primary coil 10 has 195 turns, the coil portion 11 has 105 turns, giving the secondary coil complete 300 turns, andthe coil 14 has 300 turns. The core bars 20 are of such width as to cause a close approach to saturation therein when the line voltage is at the normal 110 volts. The air gap 25 is of such size as to cause the inductance drop through the coil 14 and the counter-voltage in said coil substantially to balance the increase in voltage produced by the transformer, whereby the voltage between the leads 15 and 16 is substantially 110 volts when the line voltage is 110 volts.

In the arrangement shown in Fig. 4, the core comprises a bar 26, with arms 27 extending at right angles thereto, and an arm 28 extending in -continuation of the bar 26. Upon the outer ends of the arms 27, there are bars 29 parallel with the bar 26, the parts 26, 27, 28 and 29 being formed integrally with each other. A separately formed bar 30 is provided across the ends of the bars 29 and 26, and another separately formed bar 21 is provided at the opposite ends of the bars 29 in spaced relation to the bar 28. In this arrangement, the principal return path comprises the parts 26, 27, 29 and 30, While the auxiliary return path comprises the parts 28, 31 and 29. The coils 10 and 11 are, of course, to be mounted on the bar 26, and the coil 14 on the arm 28, the arrangement being such that the operation and effect are the same as those above described in connection with the construction shown in Fig. 1.

The description of the construction and operation above applies to the preferred form of my improved device, but the invention is not in any Way limited to some of the features as there set forth. For example, While I prefer to proportion the arms 20 so that they shall have a close approach to saturation l when the voltage in the coil 10 approaches the normal, it will be understood that my invention broadly is not limited thereto, it being evident that a device arranged with a differently selected pointof saturation would have a field of usefulness. In the same way, my invention broadly is not to be limited With respect to the size of the air gap 25 whereby the counter-voltage and the inductance drop are made to balance or oi'set the transformer increase in voltage when the line voltage is at normal strength. It might well be that the designer would prefer to have this balanced condition take place when the line voltage is either above or below such normal strength. In general, my invention is not to be limited to the form as shown and described except so fa as the claims are so limited by the prior ar I claim-f- 1. In a voltage compensator, the combina- .tlon of a core, primary and secondary coils mounted on said core in transformer rela tionship and arranged so that the voltage normally impressed on the secondary has a constant ratio to the voltage in the primary, a portion of said core means being of such reduced size as compared with the remaining -portions that upon the passage of the normal current of normal voltage through the primary coil said reduced portion of the core shall have a close approach to saturation, auxiliary core means providing a shunt return path about said core portion of reduced size for carrying a portion of the flux thread-- ing said primary and secondary coils, and auxiliary coil means mounted on said auxiliary core and connected in series with said secondary coil in opposition thereto adapted by theaction thereon of the magnetic ux through said auxiliary core to cut down the voltage through the connected secondary and auxiliary coils to a point well below the voltage normally impressed on saidl secondary coil. a l

2. In a voltage compensator, the combination of a core providing a closed magnetic circuit and comprising a portion of predetermined cross sectional size and the remaining port'on of greater cross sectional size, primary and secondary coil means mounted in transformer relationship to each other on said core portion of greater cross sectional size adapted upon the passage of the predetermined normal current of normal volt duce substantial saturation in said reduced portion of the core, auxiliary core means adjacent to said core portion of reduced size providing a shunt return path thereabout, and auxiliary coil means mounted on said auxiliary core means and connected in series with said secondary coil in oppostion thereto.

3. In a voltage compensator, the combination of a core providing a closed magnetic circuit and comprising a portion of predetermined cross sectional size and the rema'ning portion of greater cross sectional size, primary and secondary coil means mounted in transformer relationship to each other on said core portion of greater cross sectional size adapted upon the passage of the predetermined normal current of normal voltage through the pr'mary coil means to produce substantial saturation in said reduced portion of the core, auxiliary core means providing a shunt returnA path about said core portion of reduced size, and auxiliary coil means lill) said core, auxiliary coremeans providing anmounted on said auxiliary core meansin substantially non-inductive relationship to the magnetic flux passing through said core portion of reduced size and .connected in serles with said secondary coil means in opposition thereto. 4. In a voltage compensator, lthe comb1na substantial saturation in said reduced portion of the core, auxiliary core means providing a shunt return path about said core port-ion of reduced size, and auxiliarymeans mounted on saidauxiliary core means 1n sul) stantially axial alignment with said primar coil and connected in series with said secon ary coil inopposition thereto. l 5. In a voltage compensator, the combination of a core comprising a straight bar and a return path portion cooperating to provide a closedmagnetic circuit, primary and secondary coil means mounted in transformer relationship on said straight bar adapted upon. the passage 'of the normal current of normal voltage through the primary coil means to produce substantial saturation in at least a part of the return path portion of said core, auxiliary core means providing a vshunt return path about said part of the first named return path in which substantial saturation is produced and arranged to have a comparatively much higher normal ,reluctance than that of the first vnamed return path means, and auxiliary coil means'mountv ed on said auxiliary core means and connected in series with said secondary coil in opposition thereto. i

6. In a voltage compensator, the combination of a core comprising a straight bar and a. return path portion connecting anintermediate part and one end of said straight bar in a closed magnetic circuit, primary and secondary coil means mounted in transformer relationship on said straight bar adapted upon passage of the normal current of normal voltage through the primary co'il means to produce substantial saturation in lwith sald-secondarycoil means in opposition thereto.

. JOSEPH G. SOLA.

at least a part of the return path portion of l auxliary return path from the opposite end of said straight bar to said lirst named return path portion and arranged in parallelV -shunt relation to said portion of the first namedreturn path' in which substantial saturation 1s produced, and an auxiliary coil mounted on said opposite end portion of said

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