DESC:TECHNICAL FIELD

The present subject matter described herein, in general relates to circuit breakers and more particularly, to a moving contact which is used for making and breaking of contacts in a circuit breaker.

BACKGROUND

In general a circuit breaker or a moulded case circuit breaker is used in an electrical power distribution circuit of a building, a factory, a ship or so as to switch off and switch on a normal circuit and automatically break faulty circuit.

The circuit breakers are an automatically operated electrical switch designed to protect an electrical circuit from damage caused by overload or short circuit. Unlike a fuse, which operates once and then has to be replaced, a circuit breaker can be reset (either manually or automatically) to resume normal operation. A switch mechanism of the breaker can then be thrown to open and close contacts to which the load is connected.

A draw out circuit breaker is a specific type of circuit breaker configuration that is designed to be racked into and out of power equipment to connect and disconnect the circuit breaker to an electrical power source and load circuit. Mechanisms for draw out circuit breakers are typically provided for insuring that draw out circuit breakers cannot be physically connected between a line and load when the breaker is in the contacts-closed position. Many regulations require that a circuit breaker is switch off before applying padlocks and key interlocks.

In the prior art, circuit breakers with moving (upper) contact is assembled to the driveshaft along with a spring. The moving contact repels during short circuit fault and breaks the circuit. In these cases, the mechanism should open before the moving contact recloses. Reclosing of the moving contacts before opening of the drive shaft, may leads to re-strike and resulting higher fault clearing time, higher let through energy.

In addition to early fault clearing, the contact locking feature also works as backup protection to the mechanism and release failure. So, this contact locking feature provides extra protection to the circuit.

In spite of many existing mechanisms for breaking of circuit there is still a need to provide an improved, efficient contact locking mechanism for a circuit breaker to offers proper toggling with a very less angle of rotation and use the contact locking by means of toggling mechanism.

SUMMARY

This summary is provided to introduce concepts related to an improved contact locking mechanism of a circuit breaker. This summary is not intended to identify essential features of the subject matter nor is it intended for use in determining or limiting the scope of the subject matter.

In one implementation, the present invention relates to a moving contact which is used for making and breaking of contacts in a circuit breaker.

In one implementation, the present invention offers proper toggling with a very less angle of rotation.

In one implementation, the proposed toggle mechanism toggles and locks the moving contact in its final position.

In one implementation, the present invention helps to clear the fault with less time.

In one implementation, the present invention helps contact locking to eliminate the chances of contact re-closing and re-strikes.

In one implementation, an improved contact system with contact locking feature of a moulded case circuit breaker is proposed. The prime feature of present invention is to achieve the contact locking by means of a toggle mechanism.

In one implementation, the present invention the present invention is related to providing a contact locking feature to achieve an efficient breaking of circuit. Here, the moving contact(2) opens due to Lorentz force and locked in final position by means of a toggling mechanism.

In present invention, the moving (upper) contact is assembled in driveshaft with the help of toggle mechanism. The moving contact is engaged with driveshaft and spring cage by means of a link. A compression spring is assembled between the spring cage and the moving contact through the link.

During any fault, the release of the circuit breaker senses the fault and gives a signal to the mechanism to break the circuit by opening the moving contacts from fixed contacts.

During fault condition, the moving contact and fixed contact experience a high repulsion force due to electromagnetic forces and repel from each other. In the present invention the toggle mechanism locks the moving contact in repelled position and breaks the circuit. Contact opening in this process takes lesser time than contact opening through mechanism. After locking the contacts the toggle mechanism prevents the contacts from reclosing. The moving contact comes back to its original position as soon as the driveshaft comes to open position.

Accordingly in one implementation, an apparatus for a circuit breaker is disclosed. The apparatus comprises of a driveshaft (1), a moving contact (2), and a toggle mechanism. The said moving contact (2) is coupled in said driveshaft (1) using said toggle mechanism.

In one implementation, a toggle mechanism comprises of a toggle pin (3), a contact pin (4), a spring cage (5), a compression spring (6), and a pivot pin (7). The moving contact (2) and said spring cage (5) are coupled in driveshaft (1) using said contact pin (4). The compression spring (6) is placed between said spring cage (5) and said moving contact (2) taking said toggle pin (3) as axis. The said toggle pin (3) is placed in a slot provided in said spring cage (5) and further attached to said moving contact (2) by said pivot pin (7).

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to refer like features and components.

Figure 1 illustrates a sectional view of contact assembly in normal condition is shown, in accordance with an embodiment of the present subject matter.

Figure 2 illustrates a sectional view of contact assembly at the moment of toggling is shown, in accordance with an embodiment of the present subject matter.

Figure 3 illustrates a sectional view of contact assembly in contact locked condition is shown, in accordance with an embodiment of the present subject matter.

Figure 4 illustrates a sectional view of contact assembly at the moment of resetting is shown, in accordance with an embodiment of the present subject matter.
DETAILED DESCRIPTION OF THE PRESENT INVENTION

Preferred embodiments of the present disclosure will be described herein below with reference to the accompanying drawings. In the following description, well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail.

The terms and words used in the following description are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention.

It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.

By the term “substantially” it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.

In one implementation, the present invention relates to a moving contact which is used for making and breaking of contacts in a circuit breaker.

The list of components used in the invention to describe the preferred embodiment is as follows:

1. Driveshaft (1)
2. Moving (upper) contact (2)
3. Toggle Pin (3)
4. Contact pin (4)
5. Spring Cage (5)
6. Compression Spring (6)
7. Pivot Pin (7)

In one implementation, the present invention relates to an improved contact system with contact locking feature of a moulded case circuit breaker. The important feature of present invention is to achieve the contact locking by means of a toggle mechanism.

Accordingly in one implementation, an apparatus for a circuit breaker is disclosed. The apparatus comprises of a driveshaft (1), a moving contact (2), and a toggle mechanism. The said moving contact (2) is coupled in said driveshaft (1) using said toggle mechanism.

In one implementation, a toggle mechanism comprises of a toggle pin (3), a contact pin (4), a spring cage (5), a compression spring (6), and a pivot pin (7). The moving contact (2) and said spring cage (5) are coupled in driveshaft (1) using said contact pin (4). The compression spring (6) is placed between said spring cage (5) and said moving contact (2) taking said toggle pin (3) as axis. The said toggle pin (3) is placed in a slot provided in said spring cage (5) and further attached to said moving contact (2) by said pivot pin (7).

In one implementation, the present invention is characterized in that said toggle mechanism provides a proper toggling with a lesser toggling angle.

In one implementation, a breaker normal condition said compression spring (6) exerts a force on said toggle pin (3) and produces a torque on said moving contact (2) in clock wise direction, thereby producing a torque which further provides a contact pressure creating a reaction force producing a torque on said spring cage (5) in anticlockwise direction.

In one implementation, a breaker dead centre condition an anticlock wise torque is applied on moving contact (2), when said applied torque exceeds a torque provided by said spring force, said moving contact (2) starts rotating, and after a specific rotation of said moving contact (2), said toggle pin (3) axis is aligned with said moving contact (2) axis.

In one implementation, a slight rotation, after toggle pin (3) axis is aligned with said moving contact (2) axis, changes a direction of said spring force on the moving contact (2), thereby applying a torque on said moving contact (2) due to spring force in anticlockwise direction and a torque on said spring cage (5) in clockwise direction.

In one implementation, in a breaker contact locked condition said moving contact (2) continues to rotate in anticlock wise direction and said spring cage (5) rotates in clock wise direction.

In one implementation, in said moving contact (2) and said spring cage (5) stops at certain position and stays there due to spring force.

In one implementation, if a clockwise torque is provided to moving contact (2), it rotates and toggles to a reset position.

In one implementation, during a short circuit fault, high current flows through a current path of said circuit breaker wherein said moving contact (2) experiences a repulsion force due to electromagnetic forces, and said moving contact (2) starts opening by rotating in said clock wise direction thereby breaks a circuit.

In one implementation, said moving contact (2) remains at locked position after toggling and prevents said moving contact (2) from re-closing.

In one implementation, the present invention helps said circuit breaker to limit current allows energy to pass through and avoids a re-strike.

In one implementation, as soon as said toggle mechanism collapses, the driveshaft comes to open condition and reset the moving contact (2).

In one implementation, a contact system with a contact locking feature in said circuit breaker.

In one implementation, the invention provides an improved contact system by addition of contact locking feature by virtue of a toggle mechanism as shown in figures. The moving (upper) contact (2) is assembled in driveshaft (1) with the help of a pin called contact pin (4) as shown in figures. The spring cage (5) is also assembled in driveshaft (1) with the same contact pin (4). One compression spring (6) is placed between the spring cage (5) and the moving (upper) contact (2) taking toggle pin (3) as its axis. The toggle pin (3) is placed in slot provided in the spring cage (5) and also attached to the moving (upper) contact (2) by the pivot pin (7).

In this toggle mechanism the prime feature is proper toggling with a lesser toggling angle. The toggling procedure is explained in three steps as shown in figure 1, figure 2 and figure 3.

In one implementation, the figure 1 shows the normal condition of the contact system. In this condition the compression spring (6) exerts a force on toggle pin (3) and produces a torque on the moving (upper) contact (2) in clock wise direction. This torque helps to provide contact pressure. The reaction force produces a torque on spring cage (5) in anticlockwise direction. If an anticlock wise torque is applied on moving contact (2), it starts rotating as soon as the applied torque exceeds the torque provided by spring force. After some specific rotation of the moving (upper) contact (2), the toggle pin (3) axis will be aligned with the moving (upper) contact (2) axis as shown in figure 2. This is called as dead centre. A slight rotation after that will change direction of the spring force on the moving (upper) contact (2). Now the torque on the moving (upper) contact (2) due to spring force will be in anticlockwise direction and torque on spring cage (5) will be in clockwise direction. The moving (upper) contact (2) continues to rotate in anti-clock wise direction and the spring cage (5) rotates in clock wise direction. The moving contact (2) and spring cage (5) stops at certain position and stays there due to spring force as shown in figure 3. This is known as contact locked condition. Now if a clockwise torque provided to the moving (upper) contact (2), it rotates and toggles (as shown in figure 4) to reset position.

In one implementation, during a short circuit fault, high current flows through the current path of the circuit breaker. Due to high current, the moving contact (2) experiences a repulsion force due to electromagnetic forces. The moving contact (2) starts opening (rotating in clock wise direction) and breaks the circuit. The moving (upper) contact (2) stay sat locked position after toggling and prevents the moving contact (5) from re-closing. This phenomenon helps the circuit breaker to limit the current, let through energy and avoids re-strike. As soon as the mechanism collapses, the driveshaft comes to open condition and reset the moving (upper) contact (2).

Exemplary embodiments discussed above may provide certain advantages. Though not required to practice aspects of the disclosure, these advantages may include those provided by the following features:

One feature of the invention is that, the present invention offers proper toggling with a very less angle of rotation.

Another feature of the invention is that, the use of contact locking by means of toggling mechanism.

Another feature of the invention is that, the toggle mechanism toggles and locks the moving contact in its final position.

Yet another feature of the invention is that, the spring cage also toggles with the moving contacts to provide proper toggling.

Yet another feature of the invention is that, the present invention helps to clear the fault with less time.

Yet another feature of the invention is that, the contact locking eliminates the chances of contact re-closing and re-strikes.

Still another feature of the invention is that, the reduction in let through is achieved due to lesser fault clearing time. This leads to lesser stress on downstream devices.

It is understood by the person skilled in the art that, the details of the present invention

The preceding description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.

Although an improved contact locking mechanism of a circuit breaker has been described in language specific to structural features and/or methods, it is to be understood that the embodiments disclosed in the above section are not necessarily limited to the specific features or methods or devices described. Rather, the specific features are disclosed as examples of implementations of improved contact locking mechanism of a circuit breaker.
,CLAIMS:1. An apparatus for a circuit breaker, comprising:
a driveshaft (1);
a moving contact (2); and
a toggle mechanism;
wherein said moving contact (2) is coupled in said driveshaft (1) using said toggle mechanism.

2. The apparatus as claimed in claim 1, wherein said toggle mechanism comprises:
a toggle pin (3);
a contact pin (4);
a spring cage (5);
a compression spring (6); and
a pivot pin (7); wherein
said moving contact (2) and said spring cage (5) is coupled in driveshaft (1) using said contact pin(4);
said compression spring (6) is placed between said spring cage (5) and said moving contact (2) taking said toggle pin (3) as axis; and
said toggle pin (3) is placed in a slot provided in said spring cage (5) and further attached to said moving contact (2) by said pivot pin (7).

3. The apparatus as claimed in claims 1 and 2, is characterized in that said toggle mechanism provides a proper toggling with a lesser toggling angle.

4. The apparatus as claimed in claims 1-3, wherein in a breaker normal condition said compression spring (6) exerts a force on said toggle pin (3) and produces a torque on said moving contact (2) in clock wise direction, thereby producing a torque which further provides a contact pressure creating a reaction force producing a torque on said spring cage (5) in anticlockwise direction.

5. The apparatus as claimed in claims 1-4, wherein in a breaker dead centre condition
an anticlock wise torque is applied on moving contact (2),
when said applied torque exceeds a torque provided by said spring force, said moving contact (2) starts rotating, and
after a specific rotation of said moving contact (2), said toggle pin (3) axis is aligned with said moving contact (2) axis.

6. The apparatus as claimed in claim 5, wherein a slight rotation, after toggle pin (3) axis is aligned with said moving contact (2) axis, changes a direction of said spring force on the moving contact (2), thereby applying a torque on said moving contact (2) due to spring force in anticlockwise direction and a torque on said spring cage (5) in clockwise direction.

7. The apparatus as claimed in claim 1-6, wherein in a breaker contact locked condition said moving contact (2) continues to rotate in anticlock wise direction and said spring cage (5) rotates in clock wise direction.

8. The apparatus as claimed in claim 7 wherein in said moving contact (2) and said spring cage (5) stops at certain position and stays there due to spring force.

9. The apparatus as claimed in claims 7 and 8, wherein if a clockwise torque is provided to moving contact (2), it rotates and toggles to a reset position.

10. The apparatus as claimed in claims 1-7, wherein during a short circuit fault, high current flows through a current path of said circuit breaker wherein said moving contact (2) experiences a repulsion force due to electromagnetic forces, and said moving contact (2) starts opening by rotating in said clock wise direction thereby breaks a circuit.

11. The apparatus as claimed in claim 10, wherein said moving contact (2) remains at locked position after toggling and prevents said moving contact (2) from re-closing.

12. The apparatus as claimed in claim 11 helps said circuit breaker to limit current allows energy to pass through and avoids a re-strike.

13. The apparatus as claimed in claims 10-12, wherein as soon as said toggle mechanism collapses, the driveshaft comes to open condition and reset the moving contact (2).

14. The apparatus as claimed in claims 1-13 is a contact system with a contact locking feature in said circuit breaker.