US2399044A - Transfer switch - Google Patents

Description

April 3, 1946. w. D. KYLE, JR., ETAL TRANSFER SWITCH Filed April 15, 1943 2 Sheets-Sheet l AT TORNEY.

C i L L 0 z April 1946- w. D. KYLEJR, ET AL 2,399,044

' TRANSFER SWITCH Filed April 15, 1943 2 Sheets-Sheet 2 IN VENTOR. WILL/HM 17. )1 VA 51b HIV THO/V 1 Vfi/V lei 141V -A TTORNE).

Patented Apr. 23, 1946 2,399,044 TRANSFER swrron William '1). Kyle, Jr., Milwaukee, and Anthony Van Ryan, South Milwaukee, Wis., assignors to Kyle Corporation, a corporation of Wisconsin Application April 15, 1943, Serial No. 483,160

2 Claims.

This invention relates to electric power transmission and distribution systems and has to do, on the one hand, with a new method of procedure in the effectuation of line wire transpositions whereby service interruptions are avoided, and, on the other hand, with a novel quick-action transfer switch especially adapted to facilitation of the aforementioned new method.

In the transmission and distribution of electric power over three-wire systems, either singlephase or three-phase, it is desirable to balance the load so that each phase, in the case of threephase transmission, or'each pair, in the case of single-phase three-wire transmission, carries, as nearly as practicable, its pro-rata share. But due to uncontrollable vicissitudes of consumer requirements, it often happens that the lines become badly unbalanced, making it necessary, from time to time, to transfer one or more service lines or one or more distribution lines, as the case may be, from one pair of feeder wires to another-thus restoring the balance or, at least, reducing the degree of unbalance.

To effect such a transfer by first cutting one connection and then establishing another entails a service interruption which though perhaps of short duration is inevitably long enough to stop all the clocks on the affected line besides deactuating any magnetically operated motor starters that may be connected thereto.

The primary object of this invention is to devise -a method whereby the aforementioned transfers can be effected without interrupting the power supply long enough to interfere with the continued operation of equipment connected to the branch line, while at the same time precluding the occurrence of momentary short circuits during transfer operations.

A secondary object is to devise a portable quick action switch capable of being employed advantageously in carrying out the aforementioned method and without inordinate hazard to the lineman, where potentials are dangerously high.

The novel features of our new switch will be pointed out in conjunction with the detailed description which follows.

In the drawings which accompany this specification:

- Fig. l is a view in vertical section, along the line l-l of Fig. 2, of a quick action oil switch in accordance with one aspect of our-invention. Fig. 2 is a sectional view of the same switch, taken along the line 2-2 of Fig. 1; and

Figs. 3 to 8 inclusive are a series of diagrams (Cl. 200-6 7 )v illustrating, step by step, our new method of effecting transpositions without service interruptions.

We will describe first the method with reference to Figs. 3 to 8 inclusive and thereafter the switch structure of Figs. 1 and 2.

Fig; 3 shows, diagrammatically, a three-wiretransmission line or distribution line, asthe case may be, comprising three wires I, 2, and 3, re-

spectively, and a two-wire distribution or service line comprising wires 4 and 5, respectively. For convenience of description, the line which comprises wires l,'2, and 3 will be referred to as a feeder whereas the line connected thereto and comprising wires 4 and 5 will be referred to as a branch line. The feeder may be either a three phase or a three-wire single-phase line. In-the latter case wire 2 would be the grounded neutral to which one of the two branch line wires would in all cases be connected, the other branch line wire being connected to either of the remaining two feeder wiresit being understood that in those cases where the branch'line is of the threewire variety the present invention has no application.

If the feeder is of the three-phase variety and the connected branch line of the single-phase two-wire variety, the two conductors 4 and 5 can be connected to'anytwo of the feeder wires. In either-event, the connection between a two-wire branch line and a three-wire, alternating current feeder line can always be transferred from any given pair of the latter to any other pair of the same by making a single transposition. By way of clarification of that statement, it is pointed out that wires 4 and 5 (Fig. 3) can be connected across feeder wires I and 3 by transposing wire 5 only, or that wires 4 and 5 can be connected across wires l and 2 by transposing wire 4'only.

As an example of the procedure which we follow in effecting a transfer we have arbitrarily assumed that the connection at the outset-is as shown in Fig. 3 and that it is the intention to cut over to the connection shown in Fig. 4. But it is to be noted that the same procedure would be fol-' lowed if the connection were to be transferred to feeder wires and 3, except that wire 5 would be cut over instead of wire 4.

The first step is portrayed in Fig. 5 wherein the transfer switch of Figs; 1 and 2 is shown diagrammatically and identified as a whole by reference numeral 6. The switch is a single-pole double throw model, of which the three external ter-- minals are'marked A, B, and C respectively,'-while objectionable the blade is identified by reference numeral 1. The blade is composed of two arms 8 and 9, but except for mechanical reasons a single arm blade would do equally well. The switch blade is pivoted at H) and the pivotal point is connected directly to terminal A-which is the mid-point terminal. For want of more descriptive terminology and to facilitate differentiation between the three terminals of the transfer switch, the expression A terminal will be employed in this specification and the appended claims to desigmate the mid-point terminal, and the expressions B terminal and C terminal may be taken to mean, respectively, either of th two terminals so marked in Fig. 5. It will be observed that the B and C terminals are completely alternative and, therefore, the designations B and C depend entirely upon which way the switch happens to be thrown at the outset of the operation.

Arm 8 is shown in engagement with a fixed contact H, which is connected to terminal B, and arm 9 will engage fixed contact l2 when the switch is thrown to its alternate position. Contact I2 is connected to terminal 0.

In Fig. the branch line wires 4 and 5 are shown connected to the feeder line as in Fig. 3, and it will be seen that the wire 4, which is the one to be transposed, has been connected to the mid-point terminal A while the B terminal has been connected to wire 3the switch blade being in a position to complete a conductive path from junction l3 to junction M. In addition, terminal C has been connected at junction l5 to wire I.

Proceeding to Fig. 6, it will be seen that wire 4 has been cut to sever the connection between junctions I3 and I6 and that wire 4 retains its connection to Wire 3 via arm 8 of the switch blade.

The next step consists in throwing the switch to its alternate position-see Fig. 7. This brings about the desired transfer, and since the switch operates very rapidly the circuit is broken for only a very small fraction of a second-a period insuflicient to cause stoppage of clocks or deactuation of magnetically operated motor starters. It is, however, essential that the transfer switch break before making contact because otherwise lines I and 3 would be momentarily shorted.

The transfer having been effected as above described, Wire 4 is connected directly and permanently to wire I (see Fig. 8), which brings about the conversion from Fig. 1 to Fig. 4, as intended. All connections between the transfer switch and the several wires I, 3, and 4, as exhibited in Fig. 8, can then be broken-the job having been completed.

The procedure in every instance is the same, and it may be summarized as follows: (1) the mid-point or A terminal of the switch is connected to the branch wire whose connection is to be transposed; (2) the B terminal is connected to the same feeder wire as that to which the branch wire-to-be-transposed is connected at the outset and the C terminal is connected to the alternate feeder wire; (3) the original connection between the wire to be transposed and its connected feeder wire is cut; (4) the switch is operated so as to connect the A terminal with the C terminal via the switch blade; (5) the wire whose connection is to be transposed is connected directly and permanently to the alternate feeder wire; (6) all connections to the transfer switch terminals A, B, and C are broken.

The B terminal is hereby defined as that one,

other than the mid-point terminal, to which the switch blade is connected at the beginning of the operation-as per Figs. 5 and 6.

The C terminal is hereby defined as that one, other than the mid-point terminal, to which the switch blade is not connected at the beginning of the operationas per Figs. 5 and 6.

The alternate feeder wire is hereby defined as that one of the three feeder wires to which neither of the two branch line wires is connected at the beginning of the operation; also as that feeder wire to which the branch wire-to-betransposed will be connected at the completion of the operation.

It will be seen that the determination of B and C terminals depends upon the position of the switch at the outset of the operation in conformity with the above-stated definition. The position of the switch blade is indicated to the operator by the position of the switch-operating handle as hereinafter described.

Referring now to Figs. 1 and 2, the transfer switch there shown comprises a metal container I1 and a cover l8 of insulating material such as porcelain or Bakelite and removably secured to the container by means of a plurality of studs 1 5 and thumb nuts 20. A gasket 2| encircling and resting upon the rim of the container is interposed between the container and the cover and operates as a seal. Rising from and integral with cover [8 are three spaced pillars 22, 23, and 24, likewise of insulating material and designed to support, individually and respectively, terminal members A, B, and Cwhich are the terminals of like designation indicated diagrammatically in the previously described figures. Extending clownwardly from each of said terminal members and through the pillars are conductors 25, 26, and 27. These are connected at their lower ends, respectively, to the mid-point l0 and the stationary switch contacts II and I2.

Secured by means of anchor bolts 28 and depending from the under side of cover 18 is a frame comprising a horizontally extending plate 29 of insulating material from which are suspended two brackets 30, 3! which are bored in line at their lower ends to provide bearings for the support of a composite rotatable member 32 comprising a tubular shaft 33 of insulating material into the respective ends of which are secured gudgeons 34 and 35 having bearing portions which are journaled respectively in brackets 30 and 31. Gudgeon 34 has a portion of square cross-section at 34a and has a terminal lug at 3412 which is connected by means of a screw 36 to the lower end of a braided flexible conductor 3lthe latter being, in turn, connected by means of a bolt 38 to the metal bracket 30 which is connected by means of bolts 39 to the lower terminal of conductor 25.

Rotatable with member 32 and secured by means of a screw 40 to the squared portion 34a of gudgeon 34 is a two-arm switch blade I having angularly displaced arms 8 and 9. The former is intended to enter between and frictionally engage the complementary members Ila and Nb constituting stationary contact prong II, as shown in Fig. 1, while the latter is intended to enter between and frictionall engage the similar complementary members constituting stationary contact prong 12 when the switch is thrown to its alternate position. Gudgeon 35 is fixedly pinned or otherwise firmly secured to the tubular non-conductive shaft 33 and is attached at its opposite end to a double crank member 4| having a pair of diametrically opposed crank pins 42, 43.

The stationary contact prongs H and I2 are adjusted to grippingl engage'arms 8 and 9 respectively, so that a considerable force is required to effect a disengagement thereof, and the complementary members constituting said prongs are appropriately flared at'their free ends to permit said arms to enter.

Apair of aligned bushings 44, 45 are anchored in openings formed in cover I8 and serve as bearings for a shaft 46 to the outer end of which is secured a handle 60 by means of which shaft 46 i manually reciprocated rotationally through a limited angle. A second double crank 41, similar to crank 4| and having diametrically opposed pins 48, 49, is fixedly secured to shaft 46 and rotatable therewith. For the purpose of limiting the angle of rotation of shaft 46 and crank 41, the bushing 44 is extended as indicated at 4411 and provided with a laterally projecting arm 50 having an axially extending pin 5| which is interposed between a pair of spaced shoulders on the back of crank 4|-which shoulders strike pin 5| alternately and determine the limits of rotation of said crank and of shaft 46 in each direction. In Fig. 1, shaft 46 is shown in one of its limiting positions. From the position there shown the shaft is rotatable counterclockwise through an angle which will place pin 49 in the first quadrant and at approximately the same elevation as that at which pin 48 is shown; and will place pin 48 in the third quadrant at an elevation approximately the same as that at which pin 49 is shown.

Interconnecting pins 48 and 42 is a helical tension spring 52; and suspended from pin 48, to which it is pivotally attached, is a link 53 having an elongate slot 54 in which pin 42 is slideable and through which the latter projects. Interconnecting pins 48 and 43 is a second helical tension spring 55, identical with spring 52; and suspended from pin 49 is a second link 56, identical with link 53 and having an elongate slot 51 which is identical with slot 54.

By rotating shaft 46 counterclockwise, as viewed in Fig. 1, additional tension is placed on spring 55, which tends to pull contact arm 8 out of engagementwith contact prongs However, the grip of prongs on arm 8 is such as to effectively resist the tension of spring -55-said spring being too yieldable to transmit sufiicient force to break the grip-and nothing happens until link 56 has risen :SllfliOiEl'ltly to bring the bottom of slot 51 into engagement with pin 43. This creates a positive connection between cranks 4| and 41, and further rotation of shaft 46 causes, consequently, a positive rotation of blade 1, which forces arm 8 out of engagement with prongs When the grip is once broken, the tension of spring 55 causes an abrupt counterclockwise rotation of blade I and thus moves arm 9 into gripping engagement with prongs |2 immediately after breaking contact between arm 8 and prongs Reversal of the switch is effected by rotating shaft 46 clockwise, in which case spring 52 and link 53 perform the function previously described with respect to spring 55 and link 58.

As indicated in dotted lines in Fig. 1, the handle 68 is arranged to point in the direction of the terminal B or C with which the switch blade is connected. Thus, the operator is informed of the position of the switch and is thereby enabled unerringly to make the proper connections to the switch terminals. Since the transfer switch above described is ordinarily used at the top of a pole, it should be adapted for attachment in some convenient manner to the pole or a crossarm thereon. An arm 58 having a slot 59 designed to engage the head of a lag screw provides a suitable attachment means.

The interior of container preferably is lined with sheet insulation 6| for the purpose of avoiding a short circuit to ground in event of any conductive internal part breaking loose. The container preferably is filled with oil, as indicated, and all joints preferably are sealed to prevent escape of the oil.

What is claimed is:

1. In an electric switch operating mechanism including a pair of rotatable relatively spaced parallel shafts, a pair of crank members each secured intermediate its ends to one of said shafts to provide a pair of radially opposed crank arms, and a crank pin on each arm, in combination with a pair of coil springs each having its ends secured to corresponding crank pins, said springs being normally in balanced tensioned relation to normally hold said crank members in stable relation; to each other, a pair of links each having one end pivotally connected with one of said pins on on of said arms and provided with an elongated longitudinally extending slot at the 0pposite end slidably embracing a corresponding pin on the other of said arms, and switching means comprising a pair of fixed spaced contacts and pair of spaced movable contacts secured to one of said shafts and movable therewith, each of the contacts of one of said pairs being bladelike and each of the contacts of the other of said pairs being jaw-like for gripping engagement with corresponding contacts of said one of said pairs.

2. In an electric switch operating mechanism including a pair of rotatable relatively spaced parallel shafts, a pair of crank members each secured intermediate its ends to one of said shafts to provide a pair of radially opposed crank arms, and a crank pin on each arm, in combination with a pair of coil springs each having its ends secured to corresponding crank pins, said springs being normally in balanced tensioned relation to normally hold said crank members in stable relation to each other, and a pair of links each having one end pivotally connected with one of said pins on one of said arms and provided with an elongated longitudinally extending slot at the opposite end slidably embracing a corresponding pin on the other of said arms.

WILLIAM D. KYLE, JR. ANTHONY VAN RYAN.

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