US2870289A - Circuit interrupter - Google Patents

Description

n- 1959 w. D. KYLE, JR 2,870,289

- CIRCUIT INTERRUPTER Filed June 24. 1954 2 Sheets-Sheet 1 A LINE l'7 MAIN REPEATlHC-a JQDJUSTABLE LOCKOUT CIRCUIT Tum: VENT INTERRUTER DELAY L J-MAGNE'HC.

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WlLLlAM D. KYLE..,JR.

ATTO RNEY Jan. 20, 1959 w. D. KYLE, JR

CIRCUIT INTERRUPTER 2 Sheets-Sheet 2 Filed June 24. 1954 Fuel. 2

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ATTORNEY nited States Patent CIRCUIT INTERRUPTER William D. Kyle, Jr., Milwaukee, Wis., assignor to McGraw Edison Company, acorporation or Delaware Application June 24, 1954, Serial .No. 438,915

9 Claims. (Cl. 200-97) This invention relates to circuit interrupters.

It has been found that where several branch lines are supplied from a main line provided with a main line circuit interrupter and when each of these branch lines is controlled by an independent circuit interrupter that when the line circuit interrupter opens due to an excessive overload on any branch line or due to a fault directly on the main line, such as a ground fault for instance, that when the line circuit interrupter closes after a short interval of time that all of the branch line circuit interrupters will close and will apply their respective loads to the main line. Under these conditions no particular harm is done since no diversity of load is lost. On the other hand, if the line circuit interrupter remains open beyond a predetermined time the diversity of load is lost and when the line circuit interrupter closes the entire connected load is suddenly placed on the line causing an excessive rush of current and opening of the line circuit interrupter unless such line circuit interrupter is inordinately large.

This invention is designed to overcome the above noted defects and objects of this invention are to provide circuit interrupters which may be placed in the branch lines and which operate in a sequential manner and place their loads governed by each individual branch circuit interrupter upon the line in a sequentialmanner thus pre venting excessive rush of current through the line circuit interrupter following prolonged outage.

Further objects are to provide a circuit interrupter whose closing time is a function of the line voltage so that-when the line voltage is low the closing time is greater than when the line voltage is high.

A further object of this invention is to provide a circuit interrupter which will open under no load and also will open under very low line voltage conditions.

. Embodiments of the invention are shown in the accompanying drawings in which:

Figure 1 is a diagrammatic View of one form of the invention.

Figure 2 shows a fragmentary view of a modified form of the invention.

Figure 3 is the curve showing the relation between diversity of load and the time of outage.

Referring to Figure 1 of the drawings it will be seen that the circuit interrupter comprises a main switch means indicated generally by the reference character 1.

This switch means comprises a pair of stationary contacts 2 and a movable contact 3. The magnetic frame for the opening solenoid is indicated by the reference character 4 and the opening coil of the electromagnet is indicated by the reference character 5, the opening electromagnet itself being indicated generally by the reference character 6. T his circuit interrupter is biased open by means of the biasing spring 7, which bears against the lower cam-like portion 8 of a sliding collar 9 loosely mounted on the 'reciprocatory rod 10 which extends upwardly and is provided with magnetic and nonmagnetic sections as indicated. This rod 19 is provided with a ice fixed collar 11 against which the slidable sleeve 9 bears.

The closing electromagnet is indicated generally by the reference character 12 and comprises a closing coil 13 coacting with a magnetic plunger 14 which forms a portion of the rod 10. Another magnetic section of the rod 10 is indicated by the reference character 15 and coacts With the opening coil 5 of the opening electromagnet 6.

At the upper end a time delay means is indicated by the reference character 16 and has an adjustable vent 17 to determine the time delay for the downstroke or closing stroke of the circuit interrupter. The closing coil or energizing coil 13 of the circuit interrupter is connected through an auxiliary switch means indicated generally by the reference character 18. One side of the auxiliary or closing switch means 18 is connected to one side of the coil 13, the other side of the coil 13 being grounded as indicated. The auxiliary switch means 18 has its other side connected to the line 19 which is connected in turn to the main repeating lockout circuit interrupter 20.

No attempt has been made to show the insulating and conducting sections of the circuit interrupter except to show the conducting portion or movable contact means 3 of the main switch means 2 of the circuit interrupter forming the subject matter of this invention.

The circuit interrupter has its opening coil 5 connected in series between the line 19 and the load 21.

Normally, the sleeve 9 of the circuit interrupter is locked against action by means of the latch 22. This latch is biased close-d and is adapted to latch the slidable sleeve 5 in closed position against the action of the biasing spring 7. A releasing means in the form of a magnetic member 23 is biased towards latch-releasing position by means of a biasing spring 24 but is held in its normal position as shown in Figure l by the stray magnetic flux from the field structure of the circuit interrupter.

T he operation of the apparatus is as follows:

When an overload occurs the main switch means 1 is opened due to the upward motion of the rod it), during which the collar 11 which is fixed or rigidly secured to the rod 1'31 moves upwardly away from the slidable collar 9. The slidable collar 9 is normally in latched position as shown in Figure l but when the field of the opening coil 6 of the circuit interrupter collapses the releasing member 23 rocks in a clockwise direction and releases the latch 22 allowing the sleeve to move upwardly under the influence of its biasing spring '7. The upper end of the sleeve h is arranged to contact the movable portion 18' of the auxiliary switch is and close the auxiliary switch 18 against the action of its biasing spring 25. The auxiliary switch 18 is freely closed but is delayed in its opening stroke, hereinafter described, by means of the time delay means 26.

The time delay means '26 may have an adjustable vent 27 as indicated to determine the length of its delay period.

The closing coil 13 of the closing electromagnet 12 is now energized and starts the closing stroke of the circuit interrupter but such stroke is delayed by the time delay means lJ-i for a predetermined length of time. The time delay 16 imposes no delay on the upstroke of the circuit interrupters. The time delay means 26 has a longer time delay than the time delay means 15 so as to insure the closing of the circuit interrupter prior to the opening of the auxiliary switch 18.

As shown in Figure l, the circuit interrupter described and forming the subject matter of the invention is indicated generally by the reference character A. Several circuit interrupters are connected to the line 19 as indicated by the reference characters B, C, etc. These circuit interrupters may be, and preferably are, of the same type as the circuit interrupter A.

posed on the line circuit interrupter 2h.

The above described operation is the normal overload operation of the circuit interrupter. The circuit interrupters A, B, C, etc., are arranged to open for a lesser overload current value than that required to open the main circuit interrupter it which controls the supply power to the line 19.

Under normal conditions the circuit interrupter A, B, or C, closes after period of delay determined by its time delay means 16. However, if the overload for any of the circuit interrupters, A, B, C, etc., is of suificient value to cause opening of the main circuit interrupter 5 main circuit interrupter will open and therefore no voltage will be imposed on the line 7.9. When the main circuit interrupter closes voltage is against restored to the line 19 and if it closes immediately it is apparent that the circuit interrupter A will close in its normal manner. However, another effect has been produced in that all of the circuit interrnpters A, E, C, etc., have opened due to the n e-voltage opening means consisting of the members 22, 23 and 24, hercinabove described. Consequently, it is desirable that the time delay for closing for each of the several circuit interrupters A, B, C, etc., be of a different duration so that all of the load is not simultaneously im- If, on the other hand, the period of outage is of material duration the action of the circuit interrupters A, B, C, etc., is different from that hereinabove described. It is true that the circuit interrupters A, B, C, etc., close after different intervals of time and thus the normal load is gradually applied to the line. On the other hand, assume that the time of outage is very long indeed, it will be seen from Figure 3 that the diversity of load has varied considerably and if the time of outage is long enough there will be no diversity of load whatsoever as the entire load will. be applied to the line as the circuit interrupters A, B, and C finally close in regular sequence. If the heavy overload is still on the line it is apparent that the voltage on the line 19 is lower than normal and consequently the closing force due to the action of the closing coil 13 is less as the voltage imposed on the closing coil is lowered. Consequently, the time required after the voltage has been restored to the line 19 and the closing of a circuit interrupter, varies in proportion to the voltage on the line, the lower the line voltage the longer delay in closing due to the lesser force exerted by the closing coil 13.

It is obvious that if the time of outage, due to either automatic or manual operation of the interrupter 2t}, exceeds a certain predetermined length of time, for instance, as shown in Figure 3, that there will be an entire loss of diversity of load and consequently if successive loads are imposed on the line due to successive closings of the circuit intcrrupters, A, B, C, etc., the time delay for the circuit interrupters will be materially increased though their difference in time still exists but changed in proportion to the voltage of the line, each time delay of closing being correspondingly increased.

It is obvious that if the fault is directly from the line to the ground that the voltage imposed on the line when the main circuit interrupter 20 has reclosed will be very low and consequently, the circuit interrupters, A, B, C, etc., will be correspondingly delayed or will not close at all if the voltage on the line is-below a predetermined point. If the excess overload still exists after reclosing of the interrupter 2t such interrupter will continue -to open until it locks itself out. This locking out of the line circuit interrupter 2t) will occur provided the overload is sufficiently large irrespective of whether it is on a branch line or directly to the ground from the main line.

In the form of the invention shown in Figure 2 the same construction as that shown in Figure 1 is employed except that cumulative lockout means has been provided. This cumulative lockout means may be of any suitable type and is so constructed that it will restore itself provided the interruptions do not occur in sufiiciently, closely, connected sequence. If the interruptions are spaced apart a considerable interval of time the cumulative means will restore itself. I

This cumulative means .may consist of a pump indicated by the reference character 28 which supplies a limited quantity of oil to the cumulative cylinder 29 and thus raises the piston 30 in a step-by-step manner. The piston 30 is adapted to trip the toggle link mechanism indicated generally by the reference character 3 This toggle link mechanism has a fixed pivot point 32 at one end and at the other end is connected to switch means indicated generally by the reference character 33. It is normally locked slightly below dead center as shown in Figure 2, but when the piston 30 rises to a predetermined point it will cause the toggle link mechanism to break and will open the switch 33. The switch 33 may be manually reset by the operating handle 34 to thus restore the lockout means to its normal position.

Referring to the curve shown in Figure 3, it will be seen that such curve indicated by the reference character 35 shows the relation between the loss of diversity and the time of outage caused by opening of the circuit interrupter 20, see Figure 1. The upper horizontal line is zero percent diversity and the lowest horizontal line is one hundred percent diversity. The upper horizontal line also indicates the total connected load.

The normal load is indicated by the reference character as and is shown in the diagram by the intermediate horizontal line.

it is apparent that in both forms of the invention it independently of, or due to, the opening of the line circuit interrupter, severe under voltage should occur, for any reason whatsoever, that the circuit interrupter forming the subject matter of this invention, will open as the opening spring would then be released due to the lessened magnetic field from the main coil of the circuit interrupter. Under these conditions the circuit interrupter would open.

It will be seen that a novel form of circuit interrupter has been provided by this invention which will prevent the occurrence of under voltage due to the sudden inrush of current after prolonged opening of the line circuit interrupter.

it will be seen also that a circuit interrupter has been provided which when voltage is still on the line but drops below a predetermined value will cause removal of the load controlled by the circuit interrupter forming the subject matter of this invention from the line.

It is to be noted particularly that successive circuit interrupters on branch lines will close at successive intervals of time which intervals of time are adjustable so that a sequential placing of the successive loads on the line will occur thereby preventing sudden excessive rush of current when the line circuit interrupter is again closed after being open a material length of time.

It will be seen further that the circuit interrupter will respond to overload conditions freely and independently of any sequential control.

Although this invention has been described in considerable detail, it is to be understood that such description is intended as illustrative rather than limiting, as the invention may be variously embodied and is to be interpreted as claimed.

' I claim:

1. A circuit interrupter comprising switch means, elec- Ire-magnetic means responsive to overload for opening said switch means, and electromagnetic reclosing means including delay means, said reclosing means being responsive to voltage variations and its delay period being inversely related to the voltage imposed on said circuit interrupter during closing, the delay period being independent of preceding closely spaced opening operations, and independent of the magnitude of the immediately preceding overload.

2. A circuit interrupter comprising switch means, electromagnetic means responsive to overload for opening said switch means, and resetting means having a delay period inversely proportional to the voltage imposed on said circuit interrupter during the resetting operation, said resetting means including electromagnetic means for closing said switch means and delay means for delaying the resetting of said switch means, the delay period being illdependent of preceding closely spaced opening operations, and independent of the magnitude of the immediately preceding overload.

3. A circuit interrupter comprising switch means, elec tromagnetic means responsive to overload for opening said switch means, and adjustable resetting means having an adjustable delay period inversely proportional to the voltage imposed on said circuit interrupter during the resetting operation, said resetting means including electromagnetic means for closing said switch means and delay means for delaying the resetting of said switch means, the delay period being independent of preceding closely spaced opening operations, and independent of the magnitude of the immediately preceding overload.

4. A circuit interrupter arranged to be interposed between a power line and a load line comprising main switch means, overload electromagnetic means for opening said main switch means, time delay means having a delay period for delaying the closing of said main switch means, electromagnetic resetting means including an actuating coil and an armature operatively connected to said main switch means, and delayed action auxiliary switch means for operatively connecting the energizing coil of the resetting electromagnetic means to the power line, said delayed action auxiliary switch means including means for reducing the delay as the voltage increases, and the delay period of the auxiliary switch means being independent of the magnitude of the immediately preceding overload.

5. A circuit interrupter arranged to be interposed between a power line and a load line comprising main switch means, overload electromagnetic means for opening said main switch means and including a first energizing coil and an armature, said armature being operatively connected to said main switch means, a first time delay means for delaying the closing of said main switch means, electromagnetic resetting means including a second actuating coil and an armature operatively connected to said main switch means, auxiliary switch means for operatively connecting said second energizing coil to the power line, and a second time delay means for delaying the opening stroke of said auxiliary switch means.

6. A circuit interrupter arranged to be interposed between a power line and a load line comprising main switch means, overload electromagnetic means for opening said main switch means and including a first energizing coil and an armature, said armature being operatively connected to said main switch means, a first time delay means for delaying the closing of said main switch means, electromagnetic resetting means including a second actuating coil and an armature operatively connected to said main switch means, auxiliary switch means for operatively connecting said second energizing coil to the power line, and a second time delay means for delaying the opening stroke of said auxiliary switch means, said second time delay means having a longer delay period than said first time delay means.

7. A circuit interrupter arranged to be interposed between a power line and a load line comprising main switch means, overload electromagnetic means for opening said main switch means and including a first energizing coil and an armature, said armature being operatively connected to said main switch means, a first time delay means for delaying the closing of said main switch means, electromagnetic resetting means including a second actuating coil and an armature operatively connected to said main switch means, auxiliary switch means for operatively connecting said second energizing coil to the power line, spring biasing means including a movable member arranged to be operatively connected to said main switch means for opening said main switch means independently of the operation of said overload electromagnetic means and arranged to close said auxiliary switch means, and latch means restraining the action of said movable member and biased towards latch-releasing motion and held against latch releasing motion by the flux from said first coil and released upon deenergization of said overload electromagnetic means.

8. A circuit interrupter arranged to be interposed between a power line and a load line comprising main switch means, overload electromagnetic means for opening said main switch means and including a first energizing coil and an armature, said armature being operatively connected to said main switch means, a first time delay means for delaying the closing of said main switch means, electromagnetic resetting means including a second actuating coil and an armature operatively connected to said main switch means, auxiliary switch means for operatively connecting said second energizing coil to the power line, spring biasing means including a movable member arranged to be operatively connected to said main switch means for opening said main switch means independently of the operation of said overload electromagnetic means and arranged to close said auxiliary switch means, and latch means restraining the action of said movable memher and biased towards latch-releasing motion and held against latch releasing motion by the flux from said first coil and released upon deenergization of said overload electromagnetic means, said latch means being held in latched position by the stray magnetic flux from said overload electromagnetic means.

9. A circuit interrupter arranged to be interposed between a power line and a load line comprising main switch means, overload electromagnetic means for opening said main switch means and including a first energizing coil and an armature, said armature being operatively connected to said main switch means, a first time delay means for delaying the closing of said main switch means, electromagnetic resetting means including a second actuating coil and an armature operatively connected to said main switch means, auxiliary switch means for operatively connecting said second energizing coil to the power line, spring biasing means including a movable member arranged to be operatively connected to said main switch means for opening said main switch means independently of the operation of said overload electro magnetic means and arranged to close said auxiliary switch means, and latch means restraining the action of said movable member and biased towards latch-releasing motion and held against latch releasing motion by the flux from said first coil and released upon deenergization of said overload electromagnetic means, said overload electromagnetic means and said spring biasing means being mutually independent in their opening action for said main switch means.

References Cited in the file of this patent UNITED STATES PATENTS Re. 13,856 Raney Dec. 29, 1914 951,852 Smith et a1. Mar. 15, 1910 986,708 Greene Mar. 14, 1911 1,385,801 Steen July 26, 1921 1,635,061 Traver July 5, 1927 1,658,695 Traver Feb. 7, 1928 1,931,507 Reed -L--- Oct. 24, 1933 2,125,157 Gamel July 26, 1938

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