Sliding Contact System of Switchgear

Field of the invention

The present invention relates generally to a switchgear for electrical switches and more particularly, to a sliding contact system of the switchgear that withstands high leaf spring load in the switchgear.

Background of the invention

A circuit breaker typically serves two basic purposes first as a switching device for switching ON/OFF during normal operating conditions for the purpose of operation and maintenance and second as a protecting device for tripping or isolating by breaking the contacts and interrupting the fault current during abnormal conditions such as short-circuit, overload and under voltage.

In sliding contact system of a switch disconnector/changeover switch disconnector, leaf springs are generally used to maintain a contact pressure. Usually, the leaf springs are clamped between a point where the force is to be applied (on the contact joint) and a molded component where the contacts are lodged. In case of higher current rating (greater than 1250A), the contact parts being of higher dimensions and thus heavier, lead to bigger molded components lodging them. In order to drive the molded components/drive shafts, higher energy has to be applied on their coupling areas. The molded components are usually thermoset components in case of lower rating but in case where higher strength of the molded components are required (in case of higher ratings), the thermoset component is not strong enough to withstand the coupling force. In this case, thermoplastic having UTS almost 8-10 times higher than the thermoset component is apt to be used.

But thermoplastic components, unlike the thermoset components, have a tendency to deform under high temperature and pressure. Since the load delivered by the leaf spring depends on the dimension of the molded component where the leaf spring rests, any deformation in this component leads to alteration of the load delivered by the leaf spring, which is unacceptable.

Accordingly, there is a need of a sliding contact system that withstands high leaf spring load in a switchgear to overcome the drawbacks of the prior art.

Objects of the invention

An object of the present invention is to withstand a leaf spring load.

Another object of the present invention is to arrest movement of the leaf spring.

Yet another object of the present invention is to prevent transfer of direct heat from a contact point to a rotor.

Still another object of the present invention is to add a metallic component in a sliding contact system to take the leaf spring load.

Summary of the invention

Accordingly, the present invention discloses a sliding contact system of a switchgear. The sliding contact system comprises a plurality of clamps, a rotor, a terminal contact part, a plurality of leaf springs, a plurality of claddings and a plurality of moving contacts.

The rotor is adapted to undergo rotation in response to an operation of the switchgear from OFF position to ON position. The rotor includes a plurality of slots configured thereon. The plurality of clamps is positioned in the plurality of slots of the rotor. The plurality of claddings is magnetic claddings and the rotor is a thermoplastic component. The plurality of leaf springs rests between the plurality of clamps and the plurality of moving contacts. The plurality of claddings is positioned above the plurality of moving contacts. The terminal contact part allows sliding of the plurality of moving contacts thereon for making a contact.

The plurality of clamps is C-clamp and made up of steel. The plurality of clamps helps in withstanding the load of the plurality of leaf springs without allowing direct transmission of the load to the rotor, prevents transfer of direct heat from the plurality of moving contacts to the rotor and restricts/arrests the movement of the plurality of leaf springs along the direction of the plurality of moving contacts.

Brief description of drawings

Other features as well as the advantages of the invention will be clear from the following description.

In the appended drawings:

Figure 1 shows a perspective view of a clamp of a sliding contact system of a switchgear, in accordance with the present invention;

Figure 2 shows a perspective view of an open pole of a switch, in accordance with the present invention;

Figure 3 shows a perspective view of a rotor with various components of the sliding contact system, in accordance with the present invention;

Figure 4 shows a cross sectional view of the rotor assembled with the components, in accordance with the present invention; and
Figure 5 shows a front view of the clamp with a leaf spring, in accordance with the present invention.

Detailed description of the invention

The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiments.

The present invention provides a sliding contact system of a switchgear. The sliding contact system comprises a C-clamp metallic component assembled with a leaf spring in a molded component to withstand high leaf spring load in the switchgear.

The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures. These reference numbers are shown in bracket in the following description.

Referring to figures 1-5, a sliding contact system (100) of a switchgear, in accordance with the present invention is shown. The sliding contact system (100) comprises a plurality of clamps (10), a rotor (20), a terminal contact part (30), a plurality of leaf springs (40), a plurality of claddings (50) and a plurality of moving contacts (60).

The rotor (20) is adapted to undergo rotation in response to an operation of the switchgear (not shown) from OFF position to ON position. The rotor (20) includes plurality of slots (not numbered) configured thereon. In an embodiment, the rotor (20) is a thermoplastic component, the plurality of clamps (10) is a C-clamp and the plurality of claddings (50) is magnetic claddings. The plurality of clamps (10) (hereinafter the “C-clamp (10)”) prevents transfer of direct heat from the plurality of moving contacts (60) to the rotor (20). The C-clamp (10) is positioned in the plurality of slots of the rotor (20) as shown in Fig. 3. The C- clamp (10) is made of steel and has certain amount of resilience that allows self adjusting to a previous position after completion of the operation. Additionally, the C-clamp (10) plays role in restricting/arresting the movement of the plurality of leaf springs (40) along the direction of the plurality of moving contacts (60).

The plurality of moving contacts (60) is made of copper and held in position by the plurality of leaf springs (40). The plurality of moving contacts (60) slides over the terminal contact part (30) to make the contact. The terminal contact part (30) also known as fixed contact is the portion of the terminal where the contacts are made.

The plurality of leaf springs (40) rests between the C-clamp (10) and the plurality of moving contacts (60). Thus, the C-clamp (10) helps in withstanding the load of the plurality of leaf springs (40) without allowing direct transmission of the load to the rotor (20).

As shown in figure 5, the shape of the C-clamp (10) facilitates locking of the plurality of leaf springs (40) thereby arresting the movement thereof. Hence, the C-clamp (10) helps in delivering the required load to the plurality of moving contacts (60) at a right position. The C-clamp (10) further helps in transmitting the heat generated at the contact area in ON position.

The plurality of claddings (50) is positioned above the plurality of moving contacts (60) and helps in increasing the attraction force of the contacts when in ON position by channelizing magnetic flux lines. In addition to this, a projection/pip (not numbered) present on the plurality of claddings (50) helps in restricting the movement of the plurality of leaf springs (40).

Advantages of the invention

1. The C-clamp (10) with the plurality of leaf springs (40) provides higher level of flexibility and accuracy of components of the sliding contact system (100).

2. The C-clamp (10) with the plurality of leaf springs (40) facilitates mounting of the plurality of moving contacts (60), the plurality of claddings (50) and the plurality of leaf springs (40) outside the rotor (20) followed by assembling inside the rotor (20).

3. The C-clamp (10) withstands the plurality of leaf springs (40) load without directly transmitting load to the rotor (20) in an easy manner.

4. The C-clamp (10) plays role in restricting/arresting the movement of the plurality of leaf springs (40) along the direction of the plurality of moving contacts (60).

5. The C-clamp (10) also prevents direct transfer of heat from the contact point to the rotor (20).

The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, and to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but such omissions and substitutions are intended to cover the application or implementation without departing from the spirit or scope of the claims of the present invention.
,CLAIMS:We Claim:

1. A sliding contact system (100) of a switchgear, the sliding contact system (100) comprising:
a rotor (20) adapted to undergo rotation in response to an operation of the switchgear from OFF position to ON position, the rotor (20) having a plurality of slots configured thereon;
a plurality of clamps (10) positioned in the plurality of slots of the rotor (20);
a plurality of leaf springs (40) resting between the plurality of clamps (10) and a plurality of moving contacts (60);
a terminal contact part (30) allowing sliding of the plurality of moving contacts (60) thereon to make a contact; and
a plurality of claddings (50) positioned above the plurality of moving contacts (60),
characterized in that the plurality of clamps (10) is a C-clamp that helps in withstanding the load of the plurality of leaf springs (40) without allowing direct transmission of the load to the rotor (20), prevents direct transfer of heat from the plurality of moving contacts (60) to the rotor (20) and restricts/arrests the movement of the plurality of leaf springs (40) along the direction of the plurality of moving contacts (60).

2. The sliding contact system (100) as claimed in claim 1, wherein the plurality of clamps (10) is made up of steel.

3. The sliding contact system (100) as claimed in claim 1, wherein the plurality of claddings (50) is magnetic claddings and the rotor (20) is a thermoplastic component.