US1655928A - Circuit controller - Google Patents

Description

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1| Emit H N WADE CIRCUIT CONTROLLER Filed Ju y Jan. 10, 1928.

Patented Jan. 1c, 1928.

UNITED STATES "r ii: ica.

HENRY N. WADE, 0F MILWAUKEE, WISCONSIN, ASSIGNOR TO THE CUTLER-HAMMER MFG. 00., OF MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN.

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Application filed. m 19, 1919. Serial No. 312,057.

This invention relates to circuit controllers and is particularly applicable to the control.

of polyphase circuits for eifecting automatic interruption thereof under conditions of phase failure. or phase reversal or. upon predetermined reduction of the line voltage.

Various means have heretofore been proposed for securing the aforestated results but so far as applicant is aware, none of the proposed devices has proven in practice of sufficient sensitiveness to afford complete and adequate protection of the controlled circuit.

One object of the invention is that of providing a switch adapted to act automatically both upon phase reversal of a polyphase circuit and 'upon'a relatively slight variation from a predetermined value of the voltage thereof, whether such variation be general or confined to one or more phases.

Another object is that of providing a switch adapted automatically and positively to interrupt its circuit connections without deleterious arcing, under electrical conditions and to IG-BStabllSh and positively maintain such connections under conditions closely approximating such predetermined conditions.

' Another object is that of providing a switch adapted to act automatically and positively under a relatively slight actuating force against a correspondingly reduced and substantially constant opposing force.

Another object is that of providing 1 a switch mechanism utilizing the force of gravity alone to produce a substantially constant but regulable, bias thereof and operable by a relatively slight actuating force against such bias and without appreciable variation of the value of the same.

Another object is that of providing an oscillatory switch mechanism having parts adapted to effect a substantially constant gravity induced bias thereof in one direction and operable substantially without collective mass displacement .of its remaining parts with reference to the force of gravity. Other objects and advantages will hereinafter appear.

The accompanying drawing illustrates one of the embodiments which the invention may assume in practice and thesai'ne will now be described, 1t being understood that the construction illustrated is capable of modifications falling within the scope of the. appended claims.

predetermined In the drawing, Figure 1 is a front elevational view of the device;

Fig- 2 is a side elevational view thereof; While,

Fig. 3 is a diagrammatic view illustrating a proposed arrangement of a circuit connection.

Referring to the drawing, the same illus trates a switch essentially of the induction Wattmeter type and including acontacting device l..to be hereinafter described in detail, mounted for oscillation about a pivot shaft 2 and biased to a circuit closing angular position by 'means of adjustable weights 3. A. non-magnetic. conductive segment 4 is rigidly connected with the contacting device 1 and subjected to the joint influence of a pair of electromagnets 5 and 6 to be connected across differentphases of a polyphase circuit for effecting movement of said segment in a well known manner to actuate said contacting device against the bias of the weights 3. The aforedescribed partsare mounted upon a supporting frame 7, the entire switch mechanism being enclosed within a suitable metallic casing 8.

The contacting device 1 comprises a sealed and longitudinally are shaped tube 9 of vitreous or other insulating material containinga body of mercury 10 and clamped upon a segment shaped insulating support 11 depending from the pivot shaft 2, said tube being so arranged that its lowerare surface is concentric with the ivot shaft thereby permitting oscillation 0 said tube and support about the axis of said shaft withoutfvertical displacement of the mercury contained in the former. Said tube is provided upon itslower are surface with a pair of contacts comprising wells or pockets 12 and 13 containing mercury while a pair of conductors 14 and 15 having their inner ends dipping within said wells, are sealed within the respectiveends of the tubes and there terminally connected respectively with a pair ofconductive end caps 16 and 17. Said wells are of sufficient depth to insure retention of an appreciable body of mercury surrounding each of said terminals in any position which the tube may assume in operation. A pair of conductive clips 18 and 19 are adapted to surround and grip the respective end caps of the tube, said clips being secured to the support 11 by means-of I for wear.

screw bolts 20 and 21,'the latter also serving to secure a pair offlexible leads 22-and 23 in electrical. connection with said clips respectively.

The body of mercury 10 is sufficientin quantity to fill both of the wells 12 and 13 and also to extend continuously therebetween so long as the tube is in the mid position illustrated. However, upon relatively slight angular displacement of the tube, which dis placement need not in practice exceed twenty degrees, the main body of mercury remains stationary while that contained in one or the other of the wells is carried away from and slightly above the surface of such main body with consequent separation of the two portions of mercury, which separation, more: over takes place very rapidly owing to the high surface tension of the mercury. Thus assuming the conductive end elements of said tube to be connected in an electric circuit, said circuit will be quickly broken without material arcing during the foregoing action. The aforedescribed retention of a quantity of-mercury in the pockets surrounding the conductors insures that such break shall occur only between mercury surfaces, thus effectively protecting said conductors from the effects of possible arcing, whereas in order .to protect the mercury from possibledeterioration due to such cause, the space within the tube not occupied by the mercury and conductors is filled with an electrically inert volatile reducing agent, such for example, as illuminating gas, under substantially atmospheric pressure.

Obviously upon return of the tube to its mid-position circuit is re-established through the mercury with a correspondingly quick action.

The supporting frame 7 includes a VGllZlcally extending fiat portion 24 and forwardly extending end portions 25 and 26. A substantially U-shaped bracket member 27 is rigidly secured at one end to said fiat portion of the frame adjacent the center thereof to project forwardly therefrom. The parallel end portions of said bracket member carry suitable anti-friction bearings 28 and 29 for the pivot shaft 2, one or both of said bearings being axially adjustable to compensate Said shaft is mounted for oscillation within said bearings and is medially provided with an enlarged portion 30lh aving oppositely disposed shoulders 31 and 32, being furthermore screw-threaded from the shoulder'32 to its adjacent end. -The segmental support 11 and a similarly shaped locking plate 33 are mounted upon the threaded portion'of said pivot shaft and are clamped against the shoulder 32 thereof Said locking plate 18 provided with lugs 35 and 36 by means of a nut 34.

adapted to engage the sides of the support 11 .for preventing relative angular is bent forwardly to provide a lug 39 while' a bifurcated non magnetic member having upwardly projecting arms 40 and 41 is medially riveted to said lug: .The conductive segment 4 is riveted at its ends to the upper portions of the respective arms 40 and 41 whereby oscillation of said segment is adapted to effect similar movement of the :ontacting device 1 and the weights 8.

A trapezoidal bracket member 42 having forwardly extending lugs 43 and .44 is rigidly secured to the upper flat portion of the supporting frame 7 and the electromagnets 5 andfi are rivetedto said lugs respectively, being arranged with their upper portions adjacent one another and their lower. portions spaced as illustrated. The upper limb of each of said electromagnets is in terrupted adjacent its connection with the bracket 42 thus providing aligned slots, in-

dicated at 45, to receive the segment 4 and permit free oscillation of the latter under the forces developed and induced by said electromagnets when energized...

The arms 40 "and 41 are adapted respectively'to abut the outer corners of said electromagnets for limiting oscillation of the a-foredescribed -moving parts in either direction. The Weight supporting rod 38 is arranged in the plane of the pivot shaft 2 and is adapted to be maintained at a predetermined angle above its horizontal position when the contacting device occupies its 46 is provided With'spaced' terminal bolts.

47 and 48 for the connection of suitable exterior lead wires, said terminals at their.

inner ends providing means for attachment of flexible leads 22 and 23, the latter being coiled about the pivot shaft 2 and directed downwardly along the segmental support 11 for connection with the clips 18 and 19 1S aforedescribed. The portion of the pivot shaft extending forwardly from the shoulder 31 thereof is provided with insulating sleeves 49 and 50 and spaced insulating disks 51 and 5% clamped against said shoulder by means 0 oughly insulate the leads 22 and 23 from said pivot shaft and from one another.

The switch casing 8 includes a back plate 54 rigidly secured to the flat portion 24 of a look spring 53 and adaptedto thorthe supporting frame and provided with a forwardly extending rim 55. A cover member 56 is adapted'to fit snugly over the forwardly projecting end portions and 26 of said frame member, and is provided with an offset peripheral portion GT-adapted to closely ei'igage the rim thus providing a dust proof joint. An elongated stud 58 is riveted or otherwise secured to and centrally of the supporting frame fQsaid stud extending forwardly through a reduced opening in the cover member 56 and being screw threaded to receive a nut 59 for maintaining said cover member in place. i

It to be noted that practically all of the aforedescribed parts are designed and adapted to easy and expeditious manufacture by means of automatic machinery.

The various switch parts being in the positions illustrated, it is obvious that the switch is closed, the tube 9 being so disposed that the mercury therein serves to electrically connect the conductors 1e and 15, it being moreover assumed that the windings of the electromagnets 5 and 6 are energized for maintaining said parts in such position against the bias of the weights.

If at-any time the voltage supplied to said windings falls below a predetermined value, the moment effected by the coaction' of the el'ectromagnets and the segment 4 becomes insufiicient to support the weights 3 whereupon the movable switch parts are adapted to rockin a clockwise direction thereby effecting interruption of circuit by the contacting'device in the manner aforedescribed. It subsequentlythe voltage increases to a value even very sli htly above suchpredetermined value the switch at once returns to closed position thereby effecting a .quick re-establishment of the interrupted circuit.

.Furthermore upon phase reversal of the supply circuit for the electromagnet wind- .ings the torque produced thereby is reversed whereby the switch will not close under such conditions, or if previously once open.

, The moving switch parts, with the excepclosed wi ll at tion 'of the weights 3 and the supporting means therefor, are so arranged that their result-ant or collective center of gravity coincides with the axis of the pivot shaft, moreover the center of. gravity of said ,Weights and their support lies Within the,

horizontal plane passing through said axis when the conductive segment 4 is in its mid-position. Also, as aforestated, during oscillation of the switch the main body of the mercury is not displaced in a vertical direction, whereas the necessary elevation of one end of the tube and of the. small amount of mercury contained in its adjacent wellis counteracted by a substantially equal lowering of the opposite end of the tube and 1ts adjacent wall. The device being furthermore adapted to operate substantially weights or by variation of their amount the switch may be calibrated to respond at practically any desired value of the voltage supplied to the electromagnets. whereas since the mechanical advantage of said weights does not vary appreciably during the limited oscillation to which the same are susceptible, such restoring force is substantially constant, whereby the increase in voltage required to effect reclosure of the switch over that at which the switch is set to open is relatively slight and is practically uniform for all settings.

In Fig.3 the aforedescribed switch is illustrated diagrammatically as adapted to control the energizing circuit of a main switch S, the latter controllinga polyphase A. C. motor M to be supplied with current from lines L L L Said energizing circuit of the main switch extends from line L through the winding of said switch thence through a hand operated switch 60 and through the contacting device 1 to line L and is unaffected by the action of said main switch.

The windings of electromagnets 5 and 6 are permanently connected across lines L, L and'L L respectively whereby said windings are adapted to act upon the segment 4 in a manner similar to that common in induction watt meters, for maintaining the contacting device in the position illustrated. However, upon a predetermined slight voltage reduction in any line, the weights "3 7 effect oscillation of said device as aforedescribed. thus interrupting the energizing circuit of main switch S which thereupon opens and effects stopping of the motor.

Also, uponrestoration of voltage to a value but very slightly above the release value thereof the contacting device is .automati-.

cally' restored to closed circuit position thus effecting reclosure of .the main switch ond restarting of the motor.. The hand operated switch 60 provides for'de-energization and substantially a fixed position during oscillation of said support to make and break circuit, means for effecting movement of said support including an element arranged to indentations forming internal pockets, a pair ftube filling said pockets and adapted in of conductors sealed within the ends of said tube and provided exteriorly thereof with circuit connections, said conductors having portions extending within said pocketsrespectively, a quantity of mercury located within said tube, filling said pockets and adapted in one position of the tube to electrically connect the portions of said conductors located within said pockets and being further adapted upon predetermined displacement of said tube from such position to separate for breaking of such connection, a volatile gaseous reducing agent filling the space within said tube not occupied by the aforedescribcd elements, means for effecting a substantially constant gravity induced bias of said contacting device in one direction and preponderating means for maintaining said device with its parts in a given operative relation against such bias but sub Ject to release under predetermined conditions.

3. In an electric switch, the combinationwith a pivot support, of a contacting device adapted to oscillate thereabout and comprisinga sealed non-conductive tube having a regularly curved longitudinal surface arranged coaxial with said pivot, said surface being. further provided with spaced indentations forming internal pockets, spaced conductors sealed within the ends of saidtube and provided exteriorly thereof with circuit connections, said conductors having portions extending within said pockets respectively, a quantity of mercury located within said .within said tube not occupied by the aforedescribed elements.

4. An electric switch comprising, in combination, a longitudinally curved tubular insulating container, a plurality of longitudinally spaced depressions intermediate the ends of said-container, a conducting cap at each end of said container, electrodes connected with each of said caps and extending into the respective depressions, a body of conductive fluid having portions filling said depressions and movable therewith and a relatively large portion adapted to normally bridge said former portions, a support for said container pivoted concentrically with respect to the longitudinal curvature thereof and adapted upon movement thereof to effect lifting of a relatively small portion of said fiuid from the remainder thereof for circuit breaking while maintaining the center of gravity of said remaining fluid substantially undisplaced vertically.

5. An electric switch comprising, in combination, a curved tubular container, a counterbalanced support for said container pivoted concentrically withrespect thereto, a plurality of pockets in said container spaced from the respective ends thereof, a conductive cap at each end of said container having a solid electrode extending downwardly therefrom into the respective, pockets, a quantity of conductive fluid adapted to'fill said pockets and normally bridge the same, and means for effecting lifting of the fluid in certain of said pockets from the remainder thereof for circuit breaking while maintaining the center-of gravity of the remaining fluid substantially undisplaced vertically'.

In witness whereof, I have hereunto subscribed my name.

HENRY N. WADE.

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