US1014821A - Alternating-current regulator. - Google Patents

Description

E. F. GEHRKENS.

ALTERNATING CURRENT REGULATOR.

Patented Jan. 16, 1912..

APPLIOATIQN FILED MAR. 2, 1910.

lnvenflor Edward F. Gehrkens,

ntnesses:

His Attorney,

UNITED STATES PATENT o Fron.

EDWARD F. GEHRKENS, 0F PITTSFIELD, MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

ALTERNATINGEGURRENT REOULATOR.

Specification of Letters Patent.

Patented Jan. 16, 1912.

Application filed March 2, 1910. Serial No. 54 ,947.

To 1177 whom it may concern:

Be it known that I, EDWARD F. GEHRKENs. a citizen of the United States, residing at Pittsfield, county of Berkshire, State of Massachusetts, have invented certain new and useful Improvements in Alternating- Current Regulators, of which the following is a specification.

This invention relates to apparatus for controlling thevoltage of a transformer, in such manner thata transformer may be operated through a considerable range of voltage with a constant output or a constant secondary current. The control is effected by cutting outor in successive sections of the primary winding.

The object of the invention is to effect this operation smoothly and gradually, without any sudden change in voltage when a section is cut out or inserted in circuit.

In accordance with the provisions of the patent statutes, I shall hereinafter explain the best mode in which I have contemplated applying the principle of my invention in an actual embodiment thereof. The particular embodiment which I shall describe and illustrate but to which I do not limit myself comprises in general the following instrumentalities, the novel features of my invention being pointed out with particularity in the claims annexed to and made a part of this specification.

a. A transformer with taps in the primary and a secondary which may be arranged for a series parallel connection, as, I have illustrated, or, may be a simple secondary wind- A switch for connecting the secondary winding in series or in parallel. WVhile l have illustrated this switch, it will obviously not be necessary for a simple secondary wind- 1n 5. Two dial switches for changing the tap connections of the primary winding.

(Z; A switch or switches for disconnecting groups of sections after they have been cut out by the aforesaid dial switches.

e. A compensator whose winding is subdivided into a number of equal sections; the terminals of said compensator being respec tively connected permanently to the moving arms or switch blades of the two dial switches.

I f. A set of parallel contact bars respectively connected to taps led out from the subdivisions of the com ensator.

g. A set of parallel co lector bars arranged at right angles to the contact bars, and having individual resistances connected to them and to a common conductor leading to one side of the power circuit; the other side of said circuit being connected to one end of the primary winding of the transformer.

h. A movable switch member consisting of a plurality of contact fingers insulated from each other and mounted on a common carrier, said fingers being long enough .to bear at one end always on their respective collector bars, and at their other ends on one or another of the contact bars according to the position to which they may be moved by the carrier.

2'. A two-part commutator controlling .a contactor switch in series with the compensator winding, and by means of which the circuit of said winding can be opened.

j. A potential transformer may also be connected with the power circuit supplying current to a rheostat and a voltmeter; said rheostat being operated synchronously with the dial switches, as I have shown. This, however, is not necessary to my invention.

in. An operating motor,shafts and gearing for actuating the dial switches, the disconthe drawing, though this number is immaterial. The secondary winding 3 is also divided into sections, preferably two in numher; which by means of a switch e can be two sets of clips are arranged concentric with a shaft 8 on which are mounted -two switch arms or blades 9, 10, the former angularly in advance of the latter and each cooperating with its respective set of clips. The head of each blade is long enough and the spacing of the clipsis such that each blade remains in contact with each clip during the time necessary for the compensator switch to travel over all of the contact bars in both directions. 1

The shaft 8 is driven by a motor'll controlled by a reversing switch 11 or a limit switch 11; The motor is connected with 1 the shaft by intermittent gearing; such for example as the wheel 12 containing notches separated by wide teeth with concave ends to fit the periphery of the pinion 13 between its two opposite teeth, whereby the'wheel' 12 will be moved forward one tooth fer each half revolution of the pinion, and will be locked against rotation during the time ela'psing between two actuations. The p nion 13 is carried on a counter shaft 14 which is also provided with a worm gear 15 driven by a worm 16 ona short counter shaft haw ing a spur gear 17 meshing with a plnion I 18 on the motor shaft.- This train of gearing sential point being thatthecounter shaft is merely illustrative and may be varied to meet the wishes of the constructor; the es- 14 shall make one-half revolution between two actuations of the shaft 8.

At each actuation of the shaft 8 one of 'the sections of the primary winding ofthe transformer is cut out orin, depending upon the direction in which the motor is revolving. The switch blades 9, 10 are so set that when one is just about'to move from one clip to the next, theother has just engaged a clip, and during the movement of the first blade to another clip, the second blade slides along its clip in constant contact therewith. It thus appears that the sections of the primary winding are never entirely open cir cuited by the dial switches during their I movement. In order, however, to prevent the terminals of the winding from being subjected to excessive voltages, provision is made for disconnect-mg a certain number of sections after they have been cut out by the dial switches. In t-hedra'wing, the first" four sections and the second four can thus" be disconnected in succession, by means of the rotary switches 19, 20, each comprising a contact segment 21 adapted to connect the two fingers 22 in circuit with the ends of the adjacent sections of the primary winding.

The length of each segment is such that it will cease to bridge these fingers after the.

four sections which it controls have been cut out by the switch blades 9, 10. These blades are connected by conductors 23 with the terminals of a compensator 24, whose winding is divided into sections from which taps are led to contact bars 25 arranged parallel with and insulated from each other. In the drawing I have shown seven bars, but in practice this number is increased to double that number or even more, in order to secure as fine a subdivision of the changes of voltage as possible. In proximity to the contact bars, but at right angles thereto, are several insulated collector strips 26. In practice,

these strips take the form of rings mounted on a drum, on which are also carriedthe Connected with each colthe fingers are-stepped in their arrangement,

as shown, so that they do not part from a contact bar all at the same instant, but one after the other, the leading finger making contact with the next bar before the trailing finger has left the former bar. As the carrier draws the fingersover the compensator contact bars, the sections of the compensator are cut out oneafter-the other,'unt1l finally all the fingers rest on the end bar.- In order to accommodate all the. fingers, the end bars are made wider than the intermediate ones; as shown." & Any suitable gearing may be adopted for moving the carrier in synchronism with the dial switches; but I- prefer to provide the carrier with a rack 31 meshin with a sector gear 32 which can be oscillated by a connecting rod 33 pivoted to a crank 34 on the end of the counter shaft-14. The crank is so set that it passes its dead centers at the times when the pinion 13 is actuating the wheel 12, and the fingers are resting upon the end bars of the compensator; In serieswiththe' coils of the compensator is an electromagnetic switch '35, preferably of the-contactor type,"whose coil 36 is connected to a supply circuit 37 through a. circuit breaker orcommutator 38 operated by the counter shaft 14 in "synchronism with the intermittent gearing. When this contactor is deline'rgized, it opens the compensator winding, thereby breaking the circuit from the primary winding of the transformer through the compensator. This takes place as soon as all the fingers of the compensator switch are on either of the wide end bars, and before the blade of either dial switch has opened the circuit. \Vith this arrangement, no current is broken by either of the dial switches, but only by the contactor, whose contacts can be readily renewed if they burn out. compensator switch can be reduced to a minimum by having a large number of taps on the compensator. thereby reducing the voltage between the taps to a very small amount, and also by having a large number of fingers, so that there will be practically nobreaking of current but. rather a gradual 'shiftingdue to the gradually varied resist-- ances between the compensator taps, said resistances having a sufiicient capacity to permit the compensator to be left in any position.

\Vhen the higli tension power circuit is connected across the entire primary winding of thetransformer, the minimum voltage will be delivered by the secondary winding.

This is obtained when the blade 9 is on the clip a and the fingers of the compensator switch rest on the left hand end bar 25, as shown in the drawing. Itwill be noticed that the blade 10 is also in contact with the clip 7), but practically no current will flow through the switch 7, owing to the interposition of the compensator coils. The continued rotation of' the motor causes the carrier to traverse the contact bars 25, gradually cutting outthe compensator coils, until the fingers rest on the right hand end bar, and the line is then in effect connected directly to the clip I) and the first section of the primary winding is cut out. At this point, the

5 intermittent gearing operates, moving the blade 5) to the clip a, the blade 10 still remaining on the clip I). This reverses the polarity of the compensator, so that the reverse movement of the carrier which is now effected by the next half revolution of the crank proceedsto cut out the coils of the compensator from between the clips 7) and 1;; thus again gradually increasing the voltage of the secondary of the transformer.

This alternating movement of the blades 9, 1'.) and the intermittent movement of the compensator switch are continued until the entire range of voltage has been covered, or until such a voltagerhztslieen reached as is desired. By this-arrangement a continuous movement of the actuating shaft produces a uniform rarige of voltage, and i passing from one" tap to another of the primary winding an independent adjustment of the, compensator ta psis not required; b ut this The burning of the contacts of the'i adjustment is automatic and dependent upon. the shaft actuating the dial switch blade It will be obvious that while I have illustrated the actuating shaft as driven by a motor that this shaft if desired may be operated by hand, or by other suitable means.

\Vith the secondary coils in multiple, the range in the secondary voltage of the transformer, for a complete range of operation of the dial switches, is from 40 to 100 volts, assuming that the apparatus is capable of a range of from .40 to 200 volts man. To obtain a higher voltage than 100 it is necessary to open the circuit of the entire switching apparatus, so as to disconnect it from thepower circuit, and then connect the sections of the secondary winding in series by means of the switch 4. This arrangement will produce a higher voltage across the secondary winding than was previously obtained, and in order to prevent too sudden it change, the primary switching apparatus must be run back enough to secure the same voltage as before the change Was made in the connections of the secondary. This rearrangement of the dial switches must be made before they are again connected to the power circuit, and in order to enable the operator to determine the proper adjustment a voltage indicator is provided, which will show at all times what the voltage of the secondary circuit is, whether the transformer is in service or not. The preferred form of indicator is a voltmeter 39 connected to the secondary 40 of a small potential transformer whose primary 41 is across the power mains. This transformer has a double winding, each of 100 volts, arranged as shown in the drawing, and by means of a switch 42, preferably mechanically connected with the series-parallel switch 4 for the secondary of the main transformer, either the full voltage or the half voltage of the potential transformer can be thrown upon the voltmeter; the former when the secondary is connected in series and the latter when it is connected in parallel. The current from the potential transformer passes through a rheostat 4?, whose switch arm 44 is mechanically operated by the shaft 8, as by means of sprockets and an endless belt 45. The resistance is such that as the arm moves over the buttons of the rheostat the voltmeter will show approximately the. voltage of the secondary winding of the main transformer.-

In actual practice, this invention has given entire satisfaction with a transformer capable of delivering 1(300 kilo-watts, the line voltage being 2200, and the secondary voltage varying between 40 and 200; the amperes varying correspondiugly 50000 to 8000. The voltmeter shows a per fectly smooth regulation, the etliciency and from ' power factor of the installation are improved, and the apparatus is found tobe especially adapted for use with single phase low voltage transformers having large current capacity.

While I have described the disconnecting of a certain number of sections of the transformer winding from the remainder to prevent danger to the winding from excessive voltages, I do not claim this invention which is claimed in a copending application of Walter S. Moody, Serial Number 546,946, filed March 2, 1910.

A preferred embodiment of my invention has been described in the above specificatio'n. I do not limit myself to this embodiment, however, but seek in the appended claims to cover'all embodiments which will be obvious to those skilled in the art, and within the scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

-1. The combination with a transformer having its primary winding divided into sections and connected at one end with one of the supply mains, of two switches controlling alternate sections -of said winding, a compensator having its terminals connected respectively to the moving members of said switches, means for actuating said members, a connection to the other supply main, and means dependent upon said actuating means for shifting said connection from end to end of said. compensator.

2. The combination with a transformer having its primary winding divided into sections, of two switches each having stationary contacts connected to alternate sections, a movable member for each switch, means for actuating said members, a subdivided compensator having its terminals connected respectively to said members, contacts connected with the divisions of said compensator, a movable switch cooperating with said contacts, and means operating said switch dependent upon said actuating means. I

3. The combination with a transformer having its primary winding divided into sect-ions, of two dial switches having their clips connected to alternatesections, a subdivided compensator' having its terminals connected to the movable blades of said switches, contact bars connected in between the divisions of the compensator, and a carrier provided with a plurality of stepped fingers adapted to trawerse said bars.-

4. The combination with a transformer having its primary winding divided into Sections, of two dial switches having their clips connected to alternate sections, a subdlvided compensator havmgnts terminals connectedto the movable blades of said switches, contact bars connected in bet-ween the d visions of the compensator, a carrier provided with a plurality of stepped fingers adapted to traverse said bars, and means for intermittently moving said switch .blades when said fingers rest on the end bars.

5. The combination with a transformer having its primary winding divided into sections,- of two dial switches having their. clips connected to alternate sections, a common shaft for the blades of saidswitches, a subdivided compensator in circuit with said blades, a switch cooperating with the coils of said compensator, a shaft for actuating said compensator switch, and intermittent gearing between said shaft will the shaft carrying the dialswitch blades.

6. The combination with a transformer having its primary winding divided into sections, of two dial switches having their clips connected to alternate sect-ions, a subdivided compensator having its terminals connected to the movable blades of said switches, contact bars connected in between the divisions of the compensator, a carrier provided with a plurality of double ended fingers adapted to traverse said bars,- a plurality of collector strips in line with said fingers and making contact with one end thereof, means for moving said fingers over said bars while the blades of the dial switches remain stationary, and connected 95' means for shifting said blades when the fingers are at either end of their travel.

7 The combination with a transformer having its primary winding divided into sections, of two dial switches having their clips connected to alternate sections, a subdivided compensator having its terminals connected to the movable blades of said switches, a common shaft actuating the blades of said switches, contact bars con- 105 nected in between the divisions of the compensator, a carrier provided with a pluralit-y of double ended fingers adapted to traverse said bars, a plurality of col- .lect-or strips in li ne with said fingers and making contact with one end thereof, means for moving said fin ers over said bars while the blades of the ial switches remain sta tionary, and an intermittent gearing connected to the shaft shifting said blades when 1 the fingers are at either end of their -travel.

8: The combination with a transformer having its primary winding divided into sections, of dial switches for cutting-out sections, a compensator for gradually reducing the voltage of a section about to be cutout, a circuit breaker for opening the circuit through the compensator before a dial switch operates, and means operating in synchronlsm with the dial switches for act-uating said circuit breaker.

9. The combination with a transformer t having its primary winding divided into sections, of two dial switches having their clips connected to alterxlate sections, a subdivided compensator having its termlnais connected to the movable blades of said switches, contact bars connected in between the divisions of the compensator, a plurality 'of double ended fingers adapted to traverse said bars, a plurality of collector strips each having its own resistance in line with said fingers and making contact with one end thereof, means for moving said fingers over said bars While the blades of the dial switches remain stationary, and means for shifting said blades when the fingers are at Copies of this patent may be obtained for my hand this 24th day of February, 1910.

F. GEHRKENS.

\Vitnesses Lnomn BENzINoEn, SAMUEL LoNosTRn-nr.

five cents each, by addressing the fiommissioner of Patents, Washington, D. C.

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