US768941A - Circuit-breaker. - Google Patents

Description

PATENTED AUG. 30, 1904.

E. M. HEWLETT.

CIRCUIT BREAKER.

APPLICATION FILED JUNE 29, 1901.

N0 MODEL.

WITnessea.

@ if M.

4 SHEETS-SHEET 1 Inventor.

Edward M. Hewlefl.

PATENTED AUG. 30, 1904.

E. M. HEWLETT.

CIRCUIT BREAKER.

APPLICATION FILED JUNE 29. 1901.

4 SHEETS-SHEET 2.

N0 MODEL.

InvenTor.

E. M. HEWLETT.

CIRCUIT BREAKER.

APPLICATION FILED JUNE 29, 1901.

NO MODEL.

PATENTED AUG. 30, 1904.

4 SHEETS-SHEET 3.

InvenTon E dward M. Hewlefi.

flTTl No. 768,941. I PATENTED AUG. 30, 1904. E. M. HEWLETT.

CIRCUIT BREAKER.

APPLICATION FILED JUNE 29, 1901.

N0 MODEL. 4 sHEBTssHBBT 4.

Wlfnesses. v Im/entor.

Edward MHEZWIETT.

M m by MM "UNITED STATES Patented August 30, 1904.

PATENT OFFICE.

EDWVARD M. HEIVLETT, OF SOHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEWV YORK.

CIRCUIT-BREAKER.

SPECIFICATION forming part of Letters Patent No. 768,941, dated August 30, 1904.

Application filed June 29, 1901. Serial No. 66,578, (N od l.)

To all whmn/ it 771,114 concern.-

Be it known that I, EDWARD M. HEWLETT, a citizen of the United States, residing at Schen- I the resistance of the shunt-path, the drop of potential across the shunt being sufiicient to cause arcs at the opening main contacts, which burn them and necessitate frequent renewal. These main contacts are commonly in modern types of circuit-breakers made up of a heavy bundle of copper or phosphor-bronze laminae forming a structure of considerable expense, and it is especially desirable to prevent their deterioration. I protect them by forming a plurality of shunt-paths which are progressively opened after the main contacts separate, these paths progressively increasing in resistance, so that when the main contacts part there is a comparatively small drop of potential across their separating faces, insufficient to create any damage from arcing. I further decrease the possibility of such damage by so arranging the mechanism of the circuit-breaker that increased pressure is put upon the shunt-contacts at the instant when the main contacts separate, thereby increasing the conductivity of the shunt or shunts in contradistinction to a decrease of conductivity by a decrease of pressure, as follows from the ordinary construction of circuitbreakers. I further promote the convenience of the circuit-breaker by providing the final shunt, which takes the arc with carbon contacts, easily removable to facilitate renewal and so arranged as to be given a long and rapid break to extinguish the arc. The final shunt-contact is mounted on a frame independent of the main bridging-contact, and is controlled by a separate toggle, which is overset when the circuit-breaker is closed and which is mechanically so arranged as to have its toggle straightened while the bridging-contact opensand after the other shunts have opened to suddenly collapse and produce a long break on the carbon contacts.

The novel features of the invention will be hereinafter more fully set forth and will be definitely indicated in the claims appended to this specification.

1n the accompanying drawings, which illustrate the invention, Figure 1 is a side elevation of a circuit-breaker embodying my improvements shown in the act of opening at the instant when the final shunt is about to be broken. Fig. 2 is a front view of the circuitbreaker. Fig. 3 is a side elevation of the circuit-breaker in closed position, the bridging-contact and some of its parts being removed. Fig. et is a similar view of the circuit-breaker with the carbon break-contact removed. Fig. 5 is a detail of the magnetic trip, and Fig. 6 shows a group of details illustrating the construction and action of the handle-setting toggle.

Referring to the drawings, 1 represents a supporting-board of slate or other fireproof insulating material, upon which are mounted cast-iron brackets 2 2, supportingthe operative parts. Between these brackets at a point near the supporting-board are pivoted two frames, one of which carries a bridging-contact 3 and copper shunt 4, and the other of which carries a shunt-contact 5, composed jointly of copper and carbon, as will hereinafter be more fully described. The bridgingcontact may be made as usual of laminae of phospher-bronze clamped solidly in a supporting-frame and engaging terminals 6 6 of copper end on. The frame which carries the final shunt-contact 5 may be connected at its pivoted end with the terminal 6 by means of flexible conducting-strips 7 7. The final break-contacts 5 are sectional, being formed in three independently-movable parts, as indicated in Fig. 2, cooperating with companion The stationary contacts 5 are contacts 5.

held in pivoted arms 8, mounted on abracket supported above the upper terminal 6 Each of these frames is provided with a helical spring 9, connected toa stud projecting from the base-board, as shown in Figs. 1 and 3. The movements of the main and shunt contacts are controlled by independent toggles, that of the main contact (seen most clearly in Fig. 4L) being controlled by a main operatinghandle 10 and occupying when the circuitbreaker is closed a position a little short of having its centers in line, so that it would col' lapse but for the fact that it is locked by an auxiliary toggle 11, between the supportingframe and the operating-handle 10, the auxiliary toggle being controlled by a hand-trip 12 and checked when set by a stop 13. This toggle may be tripped by an arm 14, controlled by an armature 15, (most clearly shown in Fig. 5,) pivoted on the lower terminal and attracted by an iron yoke or hand 16, partially surrounding said terminal. With such heavy currents as controlled by this type of circuitbreaker the stud furnishes sufiicient magnetizing-current to effect the opening of the circuit-breaker at a desired overload. Aretracting-spring 17, the tension of which may be adjusted by a screw and indicated in Fig. 5, to calibrate the circuit-breaker, throws the arm 14 violently against a pin 18, connected with the tripping device. Thus when the circuit-breaker is closed the toggle 19 of the carbon contacts is overset, as indicated in Fig. 3, and the bridging-contact is held set by the toggle 11, the centers of which are overset, the carbon contact being held by the toggle 19,which is also overset. The circuit-breaker may be tripped by moving the handle 12 so as to knock down the toggle 11, or by an overload, which actuates the armature 15 and trips the toggle 11 through an engagement of lever 14: with pin 18.

The construction of the handle-locking toggle 11 13 will be understood more clearly from a consideration of the details shown collectively in Fig. 6, the small trip-handle 12 of which may be moved by hand to knock down the toggle and free the main handle 10, or the pin 18, secured to the same axis as the handle 12, may be struck by the trip-lever 14 to collapse the toggle. The two links of this auxiliary toggle are pivoted together, one entering a groove in the other, as indicated in the detail views, a nose or pawl 13 on the entering link engaging the rear wall of its companion link when the toggle is set, thereby forming a fixed stop in a slightly overset condition of the toggle. When the toggle is sprung by a slight movement to the other side of the line connecting the centers of the links, the spring of the bridging-contact outward causes it to collapse.

The upper contact 6 is made sufiiciently long to accommodate an engagement with one end of the.bridging-contact 3 and with a copper block carried by a shunt-contact 4, the shunt being formed by a few strips of flexible conductors clamped in the same frame with the bridging-contact, but having the lower end in permanent conductive relation to the lower terminal 6, as is clearly apparent from Figs. 1 and 4. A lug 20, mounted on one member of the shunt-toggle, limits its extent of movement in setting, and the handle member of the toggle is loosely journaled on the handle-pivot by rings 21 21, between which and the handle-socket or hub 22 there is a limited amount of free motion before cooperating lugs (indicated in dotted lines at 28 in Fig. 3) on the handle-socket and the rings engage, so that as the operating-handle is shifted either automatically or by hand it first collapses the main toggle, thereby relieving the pressure on the bridging-contact, then before the bridging-contact opens brings the lugs on the collars into engagement and puts increasing pressure on the carbon contacts, during which the shunt-contact i is opened, and then finally opens the carbon shunt by shifting its operating-toggle beyond center on the collapsing. side. The shunt-contact frame when released is free to fall by gravity to its open position and is provided on projecting points with cushions of rawhide, leather, rubber, or similar material 23 2 1 to soften the blow. The movement of the stationary carbon contacts is limited by a proj ection 25,which engages the supporting-frame after a limited amount of movement, and current is carried to these contacts by flexible conductors,as 26. (See Fig. 3.) The carbons are held in a copper or brass box 27 and may be tightened in place by set-screws on the rear, as indicated in Figs. 1 and 3. The engaging face of the box is given a slope to coincide with the slope of the active end of the carbon, and both are sloped on a curve, so that when the circuit-breaker is set, and particularly during tripping, the copper faces engage, promoting the conductivity of the shunt, and then when the shunt-toggle is collapsed a rolling movement due to the forward motion of the pivoted fixed contacts 5 is effected, gradually bringing the carbon faces into engagement, so that the rupture of the circuit occurs on carbon and the arc is drawn on that material.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent of the United States, is

1. A circuit-breaker having main and shunt contacts, and means for reducing the impedance of the shunt-circuit before the main contacts part.

2. A circuit-breaker having main and shunt contacts and mechanical connections for increasing the pressure at the shunt-contacts when the main contacts part.

3. A circuit-breaker having main and shunt contacts and toggle connections with the operating devices for increasing the pressure on the shunt-contacts before they part.

L. A circuit-breaker having an operatinghandle, a toggle for setting the circuitbreaker, and an auxiliary toggle connected with a shuntcontact, said auxiliary toggle being overset when the circuit-breaker is closed.

5. A circuit-breaker having independentlypivoted main and shunt contacts, an operating-lever, a toggle between each of the same and the operating-lemr, and means for opening them one after another.

6. A circuit-breaker having a main contact and a supplemental arcing-contact formed of a plurality of independent sections yielding in the plane of movement of the movable element.

7. A circuit-breaker having main contacts and supplemental arcing-contacts one of which is composed of a plurality of independent sections yielding in the plane of movement of the movable element, each section containing a metal face and a carbon face, and means for causing successive opening on the metal and carbon faces.

8. A circuit-breaker for currents of large amperage provided with a trip device comprising an iron yoke inclosing the major portion of the circuit-breaker stud, and an armature hinged to one side of said yoke and completing the magnetic circuit through a gap at the other side.

9. A circuit-breaker comprising a brid gingcontact, a toggle for moving the same, a setting-handle, a locking-toggle for the same, a controlling-handle for the latter, and an independently movable arcing contact opened after the bridging-contact.

10. A circuit-breaker comprising bridging and arcing contacts in different vertical planes swinging on the same center, a flexible conductor connecting the arcing-contact frame with the terminal, an operating-toggle for each contact, and means for collapsing the toggles in succession.

11. A circuit-breaker comprising a bridging-contact, a shunt-contact, independent operating-toggles, a common setting-handle, an auxiliary toggle between the operating-handle and the frame, and means for releasing the latter to open the circuit.

In witness whereof I have hereunto set my hand this 28th day of June, 1901.

EDXVARD M. HEXVLETT.

Witnesses:

BENJAMIN B. HULL, EDWARD \VILLIAMs, Jr.

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