US2089434A - Voltage regulator - Google Patents

Description

Aug. 10, 1937. J. 1.. SCHERMERHORNV VOLTAGE REGULATOR Filed 00f.. 6, 1936 3 Sheets-Sheet 1 INVENTOR $512 Z- SZZermer/farn BY I % ATTORNEY Aug. 10, 1937;

J. 1.. SCHERMERHORN VOLTAGE REGULATOR Filed Oct. 6, 1936 Sheets-Sheet 2 INVENTOR 02/97; zazzermfizmm ATTORNEY 1937. J. L. SCHERMERHORN' 2,089,434

VOLTAGE REGULATOR Filed Oct. 6, 1936 s Sheets-Sheet is INVENTOR $77 z-Afi'zerzwer'k ry ATTORNEY Patented Aug. 10, 1937 UNITED STATES VOLTAGE REGULATOR John L. Schermerhorn, East Orange, N. J., as-

signor to American Transformer Company,

Newark, N. J.

Application October 6, 1936, Serial No. 104,176

9 Claims.

This invention relates to a voltage regulator which includes a transformer having a core and winding thereon preferably arranged in the form of an auto-transformer. In many respects my .5 present regulator has many characteristics in common with the voltage regulators shown and described in Hunter paterits 1,993,007, issued March 5, 1935; and 2,014,570, issued September 17, 1935.' However, the regulator to be hereinafter described is designed more particularly for smaller currents or watt capacity.

It is the principal object of my present invention to provide a relatively low-wattage voltage regulator which will give exceedingly close 35 voltage regulation at high effic'iency; and a regulator that is cheap to manufacture yet one that is strong and durable.

Other advantages Will be discerned by one skilled in this art, from a reading of the specifi- 20 cation, taken in connection with the annexed drawings, wherein Figure l is a part-elevational and part-sectional view through the regulator, certain parts being removed or omitted from the view to better illustrate the other parts.

Figure 2 is a top plan view of Figure 1, but on a reduced scale, with all the parts positioned, except the cover which is shownin dotted line.

Figure 3 is a bottom view of Figure 1, with all 39 the parts positioned, except the cover which, as

in Figure 2, is shown in dotted line.

Figure 4 is a view on the line 44 of Figure 1.

Figure 5is a view on the line 55 of Figure 1.

Figure 6 is a view of the brush holder such as 35 shown in Figure l but of a slightly modified method of making connection to the brush holder per se.

Figure 7 is a detailed perspective view to illustrate the contact of the brush with the winding. 40 Figure 8 is a side elevation of a modified form of brush holder.

Figure 9 is a view of Figure 8 looking at the spring side of the holder.

Figure 10 is a view of the brush holder per se,

45 looking from right to left of Figure 8.

Figure 11 is an end view of the bottom part of figure 8.

Figure 12 is an elevational view of a polyphase regulator; that is to say, one using a plu- 59 rality of units shown in Figure 1.

Referring now to the details, wherein like numbers refer to corresponding parts in the various views, I is the core of a ring type transformer. As shown, the core I is preferably 55 made up of a single strip of silicon steel ribbon spirally wound into ring form, although it will be understood that the core I may be constructed in other ways; for example, it may be made out of discs or washers punched from suitable sheet stock, but a core of this construction is very wasteful in material. The spirally wound ring core has another very special advantage over a stack of discs in that, with the discs, it is necessary to provide an insulating tube fitting tightly over the outer surfaces of the discs as a back 10 support for that part of the winding which acts as a brush track or commutator. Where the core is made out of a single piece of steel ribbon, spirally wound, it provides a very solid back support so that the special insulating cylinder is 15 not required, but the core may be exteriorly wound with sheet insulation which is wrapped tightly around it and treated with a suitable insulating varnish or equivalent. This is less expensive than the special tube and makes a more satisfactory construction. This insulation around the core is indicated by the numeral 2.

Wound over the insulation 2 is awinding 3 which is of a suitable size wire chosen according to the watt capacity of the regulator. The

winding 3 is preferably cottonor fabric-covered, enamel Wire, which I have found far preferable to plain enamel wire, because the turns are better insulated, and the fabric covering will absorb the insulating varnish or equivalent, making the whole winding moisture-proof and more durable than the winding of plain enamel wire. After the core I has been wound with the winding 3, I apply, to the exterior circumferential surface thereof, a pair of spaced bands 4 and 5 which are preferably made of'treated insulating material, to prevent expansion and which serve a plurality of purposes, in one of which the bands, which are preferably made up of a plurality of turns of. treated fabric, prevent expansion of the winding, thereby serving to hold the brush or commutator section 6 securely in place between the bands, under normal operation of the movement of the brush over the track, it being understood that the insulation is removed from the winding between the bands 4 and 5 to leave a bare track surface or commutator section 6. The bands also act to prevent movement of the wires or conductors at the track or commutator section when pressure is appliedto the transformer structure by the holding-down clamps. The bands 4 and 5 also act to prevent the brush holder, to be later referred to, from coming into engagement with the the bare conlar manner, the bottom spider I has three spaced arms extending outwardly, each having a curvilinearly' shaped seat to engage insulators ll around the bottom edge of the transformer.

The spider [has a hub it which is adapted to flt over the end of the tubular member I. which is threaded at- II to receive a clamping nut II which, when set up, securely clamps the transformer between the two spiders I and I. The

arms of the spider I have extensions 'or feet i1,

having-holes ll therein for mounting the regulator on a suitable support. Also, these extensions are provided with shoulders I! for receiving and supporting an outer case l1. which has been indicated in dotted-lines and which serves to completely enclose the regulator when necessary. Also, the arms of the spider I have flanges is positioned to receive devices used in connection with the regulator.. For example, by reference to Figure 3, one pair ofthe flanges II have attached thereto, by screws", a terminal strip Ii of insulating material carrying contact studs H, II and 24. It may be noted that to the terminals "and", are connected the ends of the winding 3. Another pair of flanges ll carries a name plate 2!, on which the usual data or indicia is aiilxed. It is to be noted that the arms of the spider I have ribs 28 to further strengthen the said arms. The use of thisstyle of clamps has several advantages over solid plates, in that free circulation of air is provided through the inside of the regulator for cooling purposes. In addition, the construction described reduces the weight and assists in accurately lining up the core with, the shaft mounting, to be later described.

Located in the bottom end of the tubular member I0, is a'shouldered bushing 21 which is centrally bored to receive one end of an operating shaft 28, the bushing being fastened to the shaft 2| by a set screw 20. Mounted in the top part of the cylindrical member II is another shouldered bushing 80, through which" the shaft 28 passes and is fastened to the bushing ilibya set screw II. The top part of the shaft carries an operating hand-wheel M; The bushing '30 has an arm 82 which may be integral therewith, or which may be fastened thereto. The arm 32 extends radially outwardly over the top of the transformer and, at its extremity, there is fas- .tened'a depending member 33, at the lower end of which is fastened, in any satisfactory manner, as by screws and nuts, generally referred to as 84, a pair of spaced members SI having the two parts extending at right angles to each other, and between -which is pivotally mounted, on a stud It, a brush holder 81;

" Thebrushholder lLasshowninPlguresL l and 5, is composed of two pieces of suitable metal fastened together by bolts or studs 38 and 3!, between which is clamped a brush it. As will be seen, by reference to Figure 1, the two parts 'of the brush holder 31 are long enough to extend over the bands I and I so that, after the brush 4. becomes worn sumciently, or for any reason The arms 8 of the spider have, at'

becomes broken, the brush holder 31 will contact with the bands 4 and I, which are of insulating material and cannot contact with the track or commutator surface 8, which would injure the track surface and also short-circuit several turns of the winding. Since the brush holder 31 is pivoted at I, the-brush and holder may oscillate in averticalplane,sothat thebrush ll will be self-aligning along the track surface between the bands 4 and 8. In other words, the brush It will be held substantially parallel with each and every turn of the winding and, due to the flanged construction of the parts 35, the holder 31 will have no movement which will take the brush out of its position just described.

As shown in Figure 1, the brush is connected through a flexible conductor I with a stud 42 to which is connected a cable 43 which passes to the interior of the tubular member i0, and one or more times around the shaft 18, and through an opening 44 in the tubular member Iii, to the terminal stud 23 (see Figure 3), It is to be understood that the stud is insulated from the member 33.

The necessary pressure of the brush on the 'commutatoror track I is obtained by reason of a spring member 45. The conductor cable 43 is held in position in the arm I2 by a suitable clip 48., In the form shown in Figure 6, the cable If is carried to the brush holder 31 in a little different manner than shown in Figure 1, in that it passes through a hole 41 in the arm 32 and directly to the intermediate connecting stud 42, thereby eliminating-the hole 48 in the member I! (see Figure 5).

In Figures 8 to 11 inclusive, the brush holder and connections are somewhat different than heretofore described. In these figures, the cable 0 passes through the arm 32 as in Figure 6, but runs directly to the brush holder. and is fastened thereto by one of the studs or bolts 38. As will be seen, by reference to Figures 8 and 11, the back side of the brush holder has a semi-circu lar seat formed therein for the round head 49 of a stud or pin 50, which is slidably held by the member I! and the outer end of which is engaged by a spring 5| similar to the spring 45, but a little differently shaped. This construction allows the brush 40 to oscillate about the head ll of the pin 60 without twisting or weaving, for the same purpose as described with respect to the construction shownin Figure 1, 'thus allowing the brush to make contact throughout its entire length on a conductor of the brush track or commutator surface I. It should be noted that the arm 32 is provided with a lug 52 adapted to'engage a stop "on one of the arms of the spider 8 so as to stop the rotation of the arm I! after it is turned by the hand-wheel 54.

By. reference to Figure 1, it .is to be noted that there is a space between the lines III which marks the beginning and end of the winding of the transformer, and the stops '2 and I! are arranged on the arm 32 and clamp I so as to stop the brush 40 on opposite sides of the said space, according to how the arm 3! is turned.

. By reference to Figure '7, it will be noted that the contact end of the brush 0 is beveled so that the contact face of the brush is substantially the width of one of-the conductors, Just the same as in the heretofore referred to Hunter patents,

wherein the brush is preferably not thicker than the thickness of one of the commutator bars illustrated. Furthermore, the brush 4b is constructed of precisely the same material as the brush described in said Hunter patents; that is to say, the material is of such a nature as to have sufiiclent resistance in association with the turn of the transformer that no detrimental short-circuitoccurs when the brush passes from one conductor to the next, it being understood 'that in this condition the brush spans two adjacent conductors, so that the circuit in which the voltage is being regulated is never opened, and little or no fluctuation of current occurs therein. It may be mentioned that the width of the track is made compatible with the length of the brush so the face area will be suflicient to carry the current without overheating and sparking,

The construction of the regulator is such that a plurality of them may be mounted in tandem by bolts passing through the holes l8 in the extensions or feet H, at the same time providing a longer shaft to go through the units, the arm for each regulator being connected to the shaft.

by ,means of the necessary bearing bushings fitting in the tubular member ll), of a length to correspond to the number of units to be connected in tandem for multiple or polyphase operation of a plurality of the-regulators. Such a regulator for a three-phase circuit is shown in Figure 12, wherein the studs 51 are supplied with spacing collars and nuts 58 for holding two of the unit regulators in spaced relation. The studs 51 terminate at some point 63 to receive the threaded ends of collars 6!, thereby holding all the units in tandem relationship. The free ends of the collar Bl may be threaded at 62 for mounting the regulator on a panel, in which case, suitable brace members are engaged by the nuts 59 on the lower ends of the studs 51. Where this type of regulator is mounted on a stand or base, it may be clamped thereto by the nuts 59, it being understood that the studs 51 pass through the base or support member.

It may be noted, in passing, that if the core is made of a single strip of magnetic material as described, I prefer to anneal it after rolling it up, and before the outer insulation and winding is put on.

Furthermore, it may be mentioned that while Figure 7 shows the brush 46 with a slightly tapered point, this is not necessary, except where the regulator is of very low capacity and the wire of the transformer winding is of relatively small diameter. In the larger capacities of this type of regulator, where the turns of the winding 3 are of such size as to give the brush the necessary mechanical strength at its face, the brush is not beveled.

From what has been said, it will be seen that certain changes may be made in the details entering into the construction of my improved type of regulator. It will also be understood that while I prefer to use a single winding, the winding may be separated into a primary and secondary,

the brush running on a similarly constructed track on the secondary winding. If the primary and secondary are used, they may be arranged and connected so that the brush need only travel over a small portion of the outer periphery of the secondary.

What I claim is:

1. A voltage regulator including an annular core, a. winding surrounding said core, with means for making electrical connection thereto, said winding being bared on its outer circumferential surface to form a brush track, a tubular member centrally located within and passing through the core, clamping members carried by said tubular member at opposite ends of said core with means for clamping them against the core and winding, a shaft rotatably located within said tubular member and having an arm extending radially over one end of the winding, means for rotating the shaft, a brush holder carried by said arm, a brush carried by the holder so as to run on said track, means for making a working electrical connection to said holder, and means for preventing the holder from contacting with the track when the brush wears out or becomes broken. Y

2. A voltage regulator as set forth in claim 1, further characterized in that said lastmentioned means includes insulating bands on opposite sides of the brush track, the brush holder being of a length to overlap the bands, and the bands being of a thickness to prevent the holder from touching the track when the holder engages the bands.

3. A voltage regulator including an annular core, a winding surrounding said cor-e, with means for making electrical connection thereto, said winding being bared on its outer circumferential surface to form a brush track, a tubular member centrally located within and passing through the core, clamping members carried by said tubular member at opposite ends of said core with means for clamping them against the core and winding, a shaft rotatably located within said tubular member and having an arm extending radially over one end of the winding, means for rotating the shaft, 2. brush holder carried by said arm so as to oscillate in a plane including an element of said track, a brush carried by the holder so as to run on said track, and means positioned overthe winding adapted to engage the holder under certain conditions to prevent the holder from, engaging the track.

4. A voltage regulator as set forth in claim 1, further characterized in that the bottom end clamping member has flanges thereon for mount-- ing thereondevices such as a terminal-connecting strip carrying terminals for the winding and brush lead, and a number plate, and further characterized in that said bottom clamping member has feet for mounting the regulator, and shoulders for receiving and attaching a cover thereto.

5. A, voltage regulator including an annular core, tight fitting insulation around said core to form a solid support for a commutator or brush track, an insulated winding over said core and having a space going nearly around its outer circumferential surface .bared to form a brush track, clamping members carried by said tubular member at opposite ends of the core and having spaced arms for engaging the side of the core and winding bands going around the winding on opposite sides of said track at least to prevent expansion of the winding and movement of the commutator or track conductors when pressure is applied to the core and winding by said clamping members, a tubular member centrally located within and going through the core, means for tightening the clamping members in securing position, a shaft rotatably carried by said tubular member, means on the shaft for rotating it, an

arm for carrying current from the brush and minal located on said board, thebottom clamping member having flanges on its arms for carrying the terminal board, said arms on the bottom clamping member having shoulders to receive a cover, and also having holes therein for mounting the regulator. T

6. A voltage regulator including an annular core comprising a strip of magnetic material arranged in concentric turns initially tightly wound and covered with a tightly fitting cover of insulating material, a winding around the core on said insulating cover, said Winding being securely anchored to the core by spaced binding means and being bared, on its outer circumferential surface in a belt extending nearly around the core and between said spaced binding means, to form a commutator or brush track, a tubular member centrally located within the core, clamping members carried by the tubular member at opposite ends of the core and having parts for gripping the sides of the core and winding, a shaft rotatably and removably carried within said tubular member, means for rotating, the shaft, an arm mounted for rotation with the shaft, a brush rigging including a holder carried by said arm, a brush carried by the holder in contact with the surface of said track, the brush being substantially the width of a conductor forming part of the track, and the holder itself being mounted so as to insure that the brush is selfaligningalong the length of a conductor of the track.

7. A voltage regulator as set forth in claim 6 further characterized in that said binding means comprises two rings of material preferably of insulating tape tightly wound over the winding at opposite sides of the track.

8. A voltage regulator as set forth in claim 6, further characterized in that said brush is seated in a holder which is carried by said arm, so the brush and bolder can swing about a pivot in a plane including a conductor in said track for the purpose described.

9. A polyphase voltage regulator comprising a plurality of units arranged in tandem; each unit including an annular core, a winding surrounding the core with means for making electrical connection thereto, said winding being securely bound to the core and bared on its outer circumferential surface to form a commutator or brush track; a tubular member passing through the.

core of each of said units, sets of clamping mem-- bers carried by the tubular member, one set for each unit, at opposite ends of its core, with 'means for clamping them against their respective cores and windings, ashaft rotatably located within said tubular members and having an arm for each unit extending radially over the end of its winding; means for rotating the shaft; a brush holder carried by each of the unit arms, a brush carried by each of said holders to engage its respective commutator or track, the said clamping members having feet for receiving means to anchor the units together in spaced relation.

JOHN L. SCHERMERHORN.

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