US3206578A

US3206578A - Circuit breaker with adjustable third fluid flow time delay

Info

Publication number: US3206578A
Application number: US148112A
Authority: US
Inventors: Jr William J Pendy
Original assignee: Westinghouse Electric Corp
Current assignee: Westinghouse Electric Corp
Priority date: 1961-10-27
Filing date: 1961-10-27
Publication date: 1965-09-14
Anticipated expiration: 1982-09-14
Also published as: GB965037A

Description

2 Sheets-Sheet 1 OFF W. J. PENDY, JR

Sept. 14, 1965 CIRCUIT BREAKER WITH ADJUSTABLE THIRD FLUID FLOW TIME DELAY Filed Oct. 27. 1961 m F ax 5 I I I a INVENTOR William J. Pendy, Jr.

ATTORNEY Sept. 14, 1965 w. J. PENDY, JR

CIRCUIT BREAKER WITH ADJUSTABLE THIRD FLUID FLOW TIME DELAY 2 Sheets-Sheet 2 Filed Oct. 27, 1961 Fig 2 United States Patent 3,206,578 CIRCUIT BREAKER WITH ADJUSTABLE THIRD FLUID FLOW TIME DELAY William J. Pendy, .lr., Beaver Falls, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a

corporation of Pennsylvania Filed Oct. 27, 1961, Ser. No. 148,112 8 Claims. (Cl. 200-108) This invention relates generally to circuit brakers and more particularly to circuit breakers of the type having a hydraulic-magnetic type of tripping mechanism.

This invention is an improvement over the type of circuit breaker shown, for example, in the patent to K. W. Wilckens, Patent No. 2,360,922. The time-delay tripping operations of this hydraulic-magnetic type of circuit breaker in response to overload currents are normally controlled by the longitudinal movement of a magnetically permeable core within a solenoid coil which core moves into position to augment the magnetic pull of a pole on a tripping armature that is complementary to the pole. The tripping movement of the core is retarded by means of a coiled spring and also by means of a fluid enclosed in a tube in which the core moves. The core is normally positioned at one end of the tube and, upon tripping movement thereof, it moves to the other end of the tube, during which movement the fluid inside of the tube is displaced from one to the other end of the tube moving through an annulus which is the diiference between an external diameter of the core member and an internal diameter of the enclosing tube. This retardation of the trip ping movement of the core member provides a time delay permitting a non-tripping momentary overload in the circuit. The length of the time delay can be varied inversely as the square of the dimension of the annulus between the plunger and tube diameters.

Accordingly, an object of this invention is to provide a circuit breaker of the above-mentioned type having a hydraulic-magnetic tripping mechanism with means for varying the dimension of the annulus between the plunger and tube diameters to thereby vary the time delay of the tripping operation.

Another object of the invention is to provide an improved hydraulic-magnetic type of circuit breaker with improved means for adjusting the tripping mechanism of the circuit breaker.

A more general object of this invention is to provide an improved hydraulic-magnetic type circuit breaker having increased utility.

In accordance with one embodiment of this invention, a circuit breaker is provided with a hydraulic-magnetic tripping mechanism that comprises a solenoid coil that is Wound around a hermetically sealed non-magnetic cylinder containing a spring-loaded movable iron core member and a fluid such, for example, as a silicon fluid. The core is positioned at one end of the tube, and the enclosure at the other end of the tube is a pole piece that is positioned adjacent an armature that is pivotally supported externally of the tube. When a current above a predetermined value occurs in the circuit to be protected by the breaker, the current in the coil creates a stronger magnetic flux pulling the iron core member upward causing a still stronger magnetic field. When the magnetic field becomes strong enough, it attracts the armature causing the armature to pivot into engagement with the pole piece which movement effects automatic opening of the circuit breaker contacts. When the core member moves to the pole end of the tube, it displaces the fluid from the pole end to the opposite end of the tube, which fiuid moves through a passage comprising the annulus between an inner diameter of the tube and an outer diameter of the core member. This invention comprises means for varying the dimension of the annulus to thereby vary the speed of movement of the core member and therefore the time delay between the start of the overload current condition and the actual tripping operation. This adjustment of the aforementioned annulus is effected by means of an adjustin gmember that can be manually operated from outside of the circuit breaker housing. Thus, the adjustment of the time-delay of the breaker can be made in the field.

For a better understanding of the nature and objects of the invention, reference may be had to the following detailed description taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is a side sectional view of a circuit breaker embodying the principles of this invention, the breaker mechanism being shown in the open-circuit position;

FIG. 2 is a side elevational view, partly in section and being shown on an enlarged scale relative to FIG. 1, of the tripping mechanism of the circuit breaker; the parts thereof being shown in the normal position;

FIG. 3 is a view similar to FIG. 1 illustrating the parts of the tripping mechanism in tripping position;

FIG. 4 is a side elevation view, partly in section, of part of the tripping mechanism;

FIG. 5 is a view similar to FIG. 4 showing the tripping mechanism of FIG. 4 after an adjustment has been made; and,

FIG. 6 is a detailed view of part of the tripping mechanism as seen in FIG. 5.

Referring to the drawings and particularly to FIG. 1, a circuit braeker 3 shown therein comprises a housing comprising a base 5 and cover 7 both of which are molded from a suitable insulating material. A circuit-breaker mechanism 9 supported in the

housing

5, 7 comprises a generally U-shaped conducting member 11 having a sta tionary contact portion 13 at one end thereof. A terminal structure 15 is connected to the other end of the conducting member 11, and it extends out through a suitable opening in the base 5 to provide for connection of the conductor 11 in an electric circuit. A movable contact arm 17, having a contact portion 19 at one end thereof, is pivotal- 1y supported on an extension 21 of a supporting member 23 which member 23 has lugs 25 at its opposite sides that fit in suitable notches in the base 5 to support the member 23 in the

housing

5, 7. The movable contact arm 17 is pivotally connected to the extension 21 by means of a pivot pin 27. A torsion spring 29 that is wound around a pin 31 that is supported on the extension 21, engages in a notch 33 of the movable contact arm 17 to bias the movable contact arm 17 to the open position shown in FIG. 1.

The movable contact arm 17 is moved to close and open the

contacts

13, 19 by means of an operating mechanism 35 that comprises a toggle comprising

toggle links

37 and 39. One end of the toggle link 37 is pivotally connected to the movable contact arm 17 by means of a pin 41. One end of the toggle link 39 is pivotally connected to a lever 43 by means of a pin 45. The

toggle links

37 and 39 are connected together by means of a pivot pin 47. The lever 43 is rigidly attached to an operating lever 48 by means of a pin 49. The pin 49 pivotally supports the lever 48 on a support 50 that is attached to the supporting member 23. The operating lever 48 has a handle portion 51 extending therefrom for external manual operation of the circuit breaker. The

toggle

37, 39 is held in the thrust transmitting position shown in FIG. 1 by means of a generally U-shaped pin 53 having the lower leg thereof extending through an opening 55 in the link 37. The U-shaped pin is pivotally supported on the link 37 by the upper leg thereof which is positioned in an opening 57 in the link 37. The upper leg of the member 53 has a a curved surface that engages a latching tooth (not shown) on the link 39. As can be seen in FIG. 1, the opening 55 in the link 37 is large enough to enable pivotal movement of the U-shaped member 53 about the pivot 57. A torsion spring 63 biases the operating lever 48 clockwise to the position shown in FIG. 1, and a torsion spring 65 biases the member .53 to the latching position seen in FIG. 1.

The circuit breaker is shown in the open-circuit position in FIG. 1. When it is desired to close the breaker, the operating handle 51 is moved counterclockwise from the oil to the on position which movement, through the lever 43 and the thrust-transmitting

toggle

37, 39, moves the movable contact arm 17 into a position where the contact portion 19 thereon engages the stationary contact 13. Reverse movement of the handle member 51 from the on to the off position raises the lever '15 and therefore the

toggle

37, 39 to move the movable contact arm 17 clockwise about its pivot 27 to the open position shown in FIG. 1.

The movable contact arm 17 is automatically moved to an open tripped position by means of a tripping mechanism (FIGS. 1-5) shown generally at 69.

The tripping mechanism 69 comprises a cylindrical tube '73 having a magnetic pole piece 75 enclosing the upper end thereof. The lower end 77 (FIG. 2) of the tube is formed integral with the tube, and when the pole piece 75 is attached, the tube is hermetically sealed. The tube 73 is formed with two

cylindrical flanges

79 and 81 so that the upper part of the tube is in the form of a spool around which a conducting coil 82 is wound. The tube 73 is supported on one leg 83 of the member 23 by means of the lower flange '79.

The tube 73 contains a magnetically permeable elongated cylindrical core member 85 that is biased to the normal position at the lower end of the tube 73 by means of a compression spring 37 that is seated at one end on the pole piece 75 and at the other end on a shoulder 89 (FIG. 2) on the core member 85. The tube 73 is filled with a suitable fluid such, for example, as a silicon fluid which retards longitudinal movement of the core member 85 within the tube 73.

An armature member 93 is pivotally supported adjacent the pole piece '75 by means of a pivot pin 95 that is supported on the support 50 (FIG. 1) that is attached to the supporting member 23. The armature 93 is biased to the open position shown in FIG. 1 by means of a torsion spring 96. A tail portion 96 of the armature 93 is provided to counterbalance the armature for better vibration and shock resistance.

When the circuit breaker is in the closed position, the circuit extends from the terminal (FIG. 1) to the conducting member 11,

contacts

13 and 19, movable contact arm 17, a flexible conductor 97, the coil 82, a conductor 99, to a terminal structure 101 that extends out through a suitable opening in the housing base 5 to provide access for connection of the breaker in an electric circuit.

When normal current or current not in excess of a predetermined amount such, for example, as 125% of normal current is flowing through the coil 75, the magnetic flux that is acting on the core member 85, is insuflicient to overcome the forces working to maintain the core member 85 in the normal position shown in FIG. 2. These forces comprise the mass of the core 85, the bias of the spring 87 and the retarding action of the fluid within the tube 73. If an overload current exceeding the predetermined amount, for example 125% or more of normal rated current, passes through the coil 75, the generated magnetic flux will attract the core member 85 moving the core member upward (FIG. 2). If the overload is only momentary and if the momentary overload does not exceed a predetermined value such, for example, as ten times the normal rated current of the circuit breaker, the retarding forces will prevent movement of the core member to a tripping position and when the temporary overload sub- 4 sides, the core member will be moved back to the normal position shown in FIG. 2.

If the overload is continued for a length of time (depending on the amount of the overload), the core member 85 will reach a tripping position nearer to the poleend of the cylinder, whereupon the magnetic flux generated in the core member and the pole piece 75 is increased in intensity to such an extent that it operates to move the armature 93 against the pole piece 75. During this armature movement, a part 105 (FIG. 1) of the armature 93 engages the lower end of the member 53 moving the member 53 clockwise about its pivot 57. During this clockwise movement of the member 53, the latch portion (not shown) of the link 39 falls into a notch (not shown) in the upper leg of the U-shaped member 53 unlatching the link 39 whereupon the force of the spring 29 operates to collapse the

toggle

39, 37 effecting opening of the opening movement of the movable contact arm 17. The circuit breaker is trip-free in that the movable contact arm 17 will move to the open position upon the collapse of the

toggle

37, 39 even though the handle 51 is held in the closed or on position. It the handle 51 is not held in the on position when the breaker trips, the spring 63 will move the handle 51 to the off position moving the

toggle

37, 39 into the position shown in FIG. 1, and the latch member 53 will be rotated to the latching position (FIG. 1) by means of the spring 65. Thereafter, the parts of the breaker are positioned for a manual closing operation. A more detailed description of the similar type of operating mechanism of the circuit breaker is given in the hereinbefore mentioned patent to Wilckens, Patent No. 2,360,922.

Referring to FIGS. 2 and 3, it will be understood that when the core member 85 is moved from the lower position (FIG. 2) toward the upper position (FIG. 3) to effect an automatic tripping operation, the fluid Within the tube 73 is displaced from the upper end to the lower end of the tube moving through a passage or annulus A the dimension of which is determined by the smallest internal diameter of the tube 73 and the largest external diameter of the core member 85.

The dimension of the annulus or passage A determines the velocity of displacing movement of the fluid within the tube 73 and therefore the speed at which the core member 85 will move during a tripping operation. This invention provides improved means for varying the dimension of the annulus A to vary the speed of movement of the core member 85 to thereby vary the time delay during an automatic tripping operation.

As can be seen most clearly in FIG. 4, the tube 73 has a tapered portion 109 that extends around the tube 73 and is disposed intermediate the ends of the tube. The tapered portion 1139 leads into a lower portion 111 of the tube having a smaller external diameter than the part of the tube above the tapered portion 109. A plurality of slots 113 are provided around the tube at the tapered portion 111. An adjusting structure 115 comprising a cup-shaped member 117 that is disposed around the lower portion 111 of the tube 73, and a threaded member 119 that is screwed into a tapped insert 120 that is secured to the housing part 5. The member 119 is spun over at 121 so that it can rotate relative to the member 117. A slot 123 is provided at the lower end of the threaded member 119 to receive a screwdriver or other suitable tool. An insulating member 122 is suitably secured to the housing part 5 to insulate the

members

120 and 119 from the terminal 101.

The tube 73 comprises a material that will deform upon the addition of pressure and will substantially regain its shape when the pressure is relieved. This material is preferably a plastic type material such as a material from the family of nylon resins which are generically polyamide resins; but it may also be a metallic material such as brass.

Referring to FIG. 4, the tripping mechanism 69 is shown in a non-adjusted position. When it is desired to increase the time delay of the trip mechanism, an operator can insert a screwdriver or other tool into the slot 123 of the threaded member 119 and rotate the member 119 in a direction that will raise the adjusting part 117 to a position where it engages the tapered surface 109 of the tube 173 pressing the tube inwardly to narrow the annulus A to the position shown, for example in FIGS. 5 and 6. The notches 113 (FIGS. 1, 4 and 5) in the tapered portion 109 are provided to prevent excessive compressive stress build up on the tube 73 during adjustment of the tripping mechanism. Because of the smaller dimension of the adjusted annulus A (FIGS. 5 and 6), the fluid in the tube 73 moves, during a tripping operation, from one end of the tube to the other with less velocity. Thus, tripping movement of the core member 85 is retarded to a lesser velocity to thereby lengthen the time that it takes the member 85 to move to a tripping position. If it is thereafter desired to shorten the time delay, the member 119 can be rotated in the opposite direction to lower the member 117 whereupon the tube 73 will flex back toward its original shape enlarging the annulus or passage A. The pitch of the threads of the member 119 can determine the amount of adjusting movement of the member 117 per a full 360 rotation of the member 119, and a table can be attached to the outer part of the housing 5 to give a visual indication of the amount of time delay according to the position of the member 117.

The true rating of the circuit breaker 3 is determined by the smallest value of overload current that Will effect an automatic tripping operation. The true rating of the circuit breaker 3 can be, for example, 125% of the normal current through the breaker. Thus, the flux generated by 125% of the normal current will pull the core member 85 overcoming the bias of the spring 87 to move the member 85 into engagement with the pole piece 75 whereupon the flux becomes strong enough to pull the armature 93 into the tripping position seen in FIG. 3 to effect a time-delay tripping operation.

As the overload current increases from 125% to, for example, 1000% of normal current, the flux generated in the pole piece 75 will actuate the armature 93 when the core member 85 is in a lower position from that seen in FIG. 3 until, at 1000% of normal current, the flux generated is strong enough to pull the armature into tripping position even when the core member 85 is at the lowermost position seen in FIG. 2. Thus, the time delay of a tripping operation is shortened as the current increases and, the circuit breaker will trip instantaneously upon the occurrence of a severe overload such as 1000% or more of normal current.

The true rating of the circuit breaker is not effected by the improved adjusting means of this invention. Adjustment of the annulus A does not aitect either the magnetic pulling force generated by the current in the coil 82 or the amount of resistance offered by the biasing spring 87. Thus, only the velocity of movement of the core member 85 and, therefore, only the time delay is affected by adjustment of the tripping mechanism 69. Moreover, since instantaneous tripping operations are effected when the current is severe enough to trip the breaker when the core member 85 is in the lowermost position in which it is shown in FIG. 2, adjustment of the annulus A does not vary the tripping characteristic regarding the amount of current necessary to effect instantaneous tripping of the breaker.

From the foregoing description, it is apparent that there is provided by this invention an improved circuit breaker with improved externally accessible means for adjusting the time delay of the hydraulic-magnetic tripping mechanism of the breaker.

While the invention has been disclosed in accordance with the provisions of the patent statutes, it is to be understood that various changes in the structural details thereof may be made without departing from some of the essential features of the invention. It is desired, therefore, that the language of the appended claims be given the broadest reasonable interpretation permissible in the light of the prior art.

I claim as my invention:

1. A circuit breaker comprising, in combination, an insulating housing, a circuit-breaker mechanism supported within said housing and comprising a pair of contacts, a trip mechanism comprising a tubular member supported to prevent axial movement thereof, said tubular member having a fluid therein, an elongated member disposed loosely within said tubular member whereby a passage is formed between said elongated member and said tubular member, upon the occurrence of certain overload current conditions said elongated member moving from one end toward the other end of said tubular member to effect opening of said contacts during which movement .a portion of said fluid is dis placed through said passage from said other end to said one end of said tubular member, and means operable from outside of said housing to adjust said passage to vary the velocity of displacement of said fluid to thereby vary the speed of movement of said elongated member.

2. A circuit breaker comprising, in combination, a pair of cont-acts, an electromagnetic trip mechanism comprising a tube, a pole piece at one end of said tube, an elongated core member movable longitudinally within said tube, means biasing said core member away from said pole piece, an armature movable toward said pole piece to effect opening of said contacts, upon the occurrence of certain overload current conditions said core member moving toward said pole piece to effect attraction of said armature ot said pole piece to thereby effect opening of said contacts, and means operable to flex said tube to vary an internal diameter of said tube to thereby vary the speed of movement of said core member within said tube.

3. A circuit breaker comprising, in combination, an insulating housing, separable contacts disposed within said housing, an electro-magnetic trip mechanism disposed within said housing and comprising a tube, a pole piece at one end of said tube, a core member movable within said tube, means biasing said core member away from said pole piece, an armature movably supported externally of said tube and in proximity to said pole piece, upon the occurrence of certain overload current conditions said core member moving toward said pole piece to effect attraction of said armature to said pole piece to thereby eflect separation of said contacts, and means adjustable from outside of said housing to deform said tube to vary an internal diameter of said tube to thereby adjust the speed of movement of said core member within said tube.

4. A circuit breaker comprising, in combination, an insulating housing, a circuit-breaker mechanism supported within said housing and comprising a stationary contact, a movable contact cooperable with said stationary contact to open and close an electric circuit, an electro-magnetic trip mechanism comprising a tubular member supported to prevent axial movement thereof, said tubular member having an enclosure at a first end thereof, said enclosure being of magnetizable material forming a pole piece, a magnetizable core member disposed loosely within said tubular member whereby a passage is formed between said core member and said tubular member, means biasing said core member toward a second end of said tubular member, an armature movably supported externally of said tubular member and being movable toward said pole piece to effect opening of said contacts, a current-carrying coil disposed around said tubular member and energized by certain current values to cause said core member to move from said second end toward said first end to thereby eifect attraction of said armature to said pole piece, a fluid in said tube to retard movement of said core member, at least a portion of said fluid being displaced through 'said passage from one end of said core member to the other end during said movement of said core member, and means operable from outside of said housing for ad justing said passage tothereby adjust the speed of movement of said core member.

5. In a circuit breaker, a pair of cooperating contacts, an electro-magnetic trip mechanism comprising a flexible tube having a tapered portion intermediate its ends, a pole piece at one end of said tube, an elongated core member movable longitudinally within said tube, means biasing said core member away from said pole piece, an armature magnetically movable toward said pole piece to effect opening of said contacts, upon the occurrence of certain abnormal current conditions said core member moving toward said pole piece to eifect attraction of said armature to said pole piece, and adjusting means manually operable to be moved against said tapered portion to vary the internal diameter of said tube adjacent said tapered portion to thereby adjust the speed of movement of said core member.

6. A circuit breaker comprising, in combination, separable contacts, an electro-magnetic trip mechanism comprising a flexible elongated tube having an external tapered portion intermediate its ends, a pole piece at one end of said tube, a core member disposed Within said tube, means biasing said core member to the other end of said tube, an armature movably supported externally of said tube and being movable toward said pole piece to effect opening of said contacts, an electrical conductor disposed externally of said tube, upon the occurrence of certain abnormal current values in said conductor said core member becoming magnetically energized sufficiently to move toward said pole piece, a fluid in said tube movable past said core member to retard movement of said core member when said core member moves toward said pole piece, adjusting means comprising a member movable to engage said tapered portion and flex said tube to vary the passage of said fluid to thereby vary the speed of movement of said core member, and a plurality of notches in said tapered portion to prevent an excessive build-up of stress when said tube is flexed.

7. A circuit breaker comprising, in combination, a stationary contact, a movable contact movable into and out of engagement with said stationary contact to close and open an electric circuit, an electromagnetic trip device comprising an elongated tube having an external tapered portion, a core member movable longitudinally within said tube to effect opening of said contacts, a fluid disposed Within said tube to retard said movement of said core member, adjusting means comprising a gen erally tubular structure, means for moving said generally tubular structure against said tapered portion to flex said tube to thereby vary the retarding action of said fluid.

8. A circuit breaker comprising, in combination, an insulating housing, a circuit-breaker mechanism disposed Within said housing and comprising a pair of contacts, a trip mechanism comprising an elongated tubular member having an external tapered portion intermediate its ends, a pole piece enclosing one end of said tubular member, an elongated core member movable longitudinally within said tubular member, a fluid disposed Within said tubular member to retard movement of said core member, spring means biasing said core member toward the other end of said tubular member, an armature movably supported externally of said tubular member, an electrical conductor disposed externally of said tube, upon the occurrence of certain overload current conditions in said conductor a magnetic flux operating to move said core memher from said other end to said one end to elTect attraction of said armature to said pole piece to thereby efifect opening of said contacts, adjusting means comprising a tubular structure, and means manually operable from outside of said housing to move said tubular structure against said tapered portions to flex said tube to thereby vary the retarding action of said fluid.

References tCited by the Examiner UNITED STATES PATENTS 1,217,469 2/17 Loguin 317l78 1,768,949 7/ 30 Denison 20097 2,360,922 10/44 Wilckens 317-178 2,690,528 5/54 Wilckens 200-408 2,700,711 1/55 Wilckens 200l08 2,990,460 6/61 Worth et a1. 20034 2,990,462 6/61 Dietz 200-108 BERNARD A. GILHEANY, Primary Examiner.

MAX L. LEVY, Examiner.

Claims

1. A CIRCUIT BREAKER COMPRISING, IN COMBINATION, AN INSULATING HOUSING, A CIRCUIT-BREAKER MECHANISM SUPPORTED WITHIN SAID HOUSING AND COMPRISING A PAIR OF CONTACTS, A TRIP MECHANISM COMPRISING A TUBULAR MEMBER SUPPORTED TO PREVENT AXIAL MOVEMENT THEREOF, SAID TUBULAR MEMBER HAVING A FLUID THEREIN, AN ELONGATED MEMBER DISPOSED LOOSELY WITHIN SAID TUBULAR MEMBER WHEREBY A PASSAGE IS FORMED BETWEEN SAID ELONGATED MEMBER AND SAID TUBULAR MEMBER, UPON THE OCCURRENCE OF CERTAIN OVERLOAD CURRENT CONDITIONS SAID ELONGATED MEMBER MOVING FROM ONE END TOWARD THE OTHER END OF SAID TUBULAR MEMBER TO EFFECT OPENING OF SAID CONTACTS DURING WHICH MOVEMENT A PORTION OF SAID FLUID IS DISPLACED THROUGH SAID PASSAGE FROM SAID OTHER END TO SAID ONE END OF SAID TUBULAR MEMBER, AND MEANS OPERABLE FROM OUTSIDE OF SAID HOUSING TO ADJUST SAID PASSAGE TO VARY THE VELOCITY OF DISPLACEMENT OF SAID FLUID TO THEREBY VARY THE SPEED OF MOVEMENT OF SAID ELONGATED MEMBER.