Claims:1. A trip circuit for earth leakage module (EL) comprising:
- a housing
- a circuit breaker assembly in said housing for making and breaking an electrical connection comprising a connected a flux shift device (FSD) and Electronic trip unit (ETU);
WHEREIN earth leakage module senses the leakage current to drive the 1strelay which disconnects the ETU’s connection to the FSD thereby driving the second relay connecting the FSD to the earth leakage module and tripping the circuit breaker.

2. The trip circuit as claimed in claim 1, wherein the said ETU is powered by current transformers.

3. The trip circuit as claimed in claim 1, wherein the circuit further comprises of means for amplifying or switching electronic signals.

4. The trip circuit as claimed in claim 3, wherein the said means is a MOSFET.

5. The trip circuit as claimed in claim 1, wherein when the first relay opens up to disconnect the ETU from the FSD.

6. The trip circuit as claimed in claim 1, wherein a microcontroller provides time delay between the first and second relay.

7. The trip circuit as claimed in claim 1, wherein no two devices will be connected to FSD at the same time.

8. A trip circuit for in earth leakage module (EL) comprising:
- a housing
- a circuit breaker assembly in said housing for making and breaking an electrical connection comprising a connected a flux shift device (FSD) and Electronic trip unit (ETU);
- means for amplifying or switching electronic signals is a mosfet;
- an earth leakage device connected with the ETU;
- a microcontroller for delaying the two relays;
WHEREIN
ETU senses the fault and gives a trip command then mosfet M2 is turned on which is inside the ETU there by tripping the circuit breaker; and when EL module senses the fault, EL controller turns the port pin on thereby making the relay turn to open state, so that the FSD is disconnected from the ETU and then the EL controller makes the other port pin high, thereby turning the relay from open state to closed state and connecting the FSD to EL module and then controller makes another port pin high and mosfet turns on thereby tripping the circuit breaker.

9. The trip circuit as claimed in claim 8 wherein relay used in the circuit is a NC contact relay.

10. The trip circuit as claimed in claim 8 wherein the FSD is always connected to the ETU even if the Earth leakage device is not powered.
, Description:TECHNICAL FIELD OF THE INVENTION

The present subject matter described herein, in general, relates to earth leakage devices, and more particularly to trip circuit used in Earth leakage module of circuit breaker.

BACKGROUND

Earth leakage devices are used to protect the people and appliances from residual currents. Many times it is used in conjunction with the circuit breaker. The circuit breaker has its own Electronic trip unit (ETU) to sense the current and accordingly trip the device either in overload or short circuit using a Flux shift device (FSD). Earth leakage devices do not have a breaking mechanism as with the circuit breaker. So to trip the load they need to somehow send the signal to the trip plate which acts upon the breaking mechanism thereby separating the contacts. Normally it’s done using another FSD connected to the trip plate or in case of high end ETU’s where communication is present, wherein the earth leakage devices are connected through some communication medium to send the signal to ETU and the ETU sends a trip command to the tripping device. But in such situations for earth leakage devices to be present, there is a need of high end ETU’s without them there won’t be any signal send to the tripping device. Thus there is need for an electronic circuit where in only one FSD can be used to trip the circuit breaker.

In the prior-art documents, US6784770B2 patent discloses an actuating mechanism in which earth leakage module and the circuit breaker are connected mechanically. It has an inbuilt tripping mechanism which has a plunger connected to the auxiliary switch carrier acting on the trip plate of the tripping mechanism of the circuit breaker. No space is required inside the breaker as the actuating mechanism is built inside the earth leakage module. Mechanical linkage to the trip plate has to be provided in the circuit breaker as it operates when the plunger is actuated when an earth leakage occurs.

In the prior-art document, US4786885A patent discloses a shunt trip to actuate the circuit breaker for using the different electrical accessories. For tripping the different electrical accessories which are connected to the circuit breaker, an additional shunt trip is required with the existing FSD for tripping the circuit breaker. It takes the space of the shunt which can be used by other devices to trip the circuit breaker. No mechanical linkage is required inside the circuit breaker.

In the conventional circuit breakers the ETU is connected to FSD and the other devices like earth leakage devices are connected to the ETU through some communication medium or connected to another tripping device which is also connected to the trip plate like the FSD. However these conventional electronic circuits including the above mentioned prior-art documents but not limited to it, have drawbacks related to having other communication medium as below:

• The communication medium either would be separate for example: Using a separate shunt trip device to operate or it would be a separate mechanism to trip the circuit breaker.
• If shunt trip is used then it uses the space for actuating a separate electrical contacts to trip the circuit breaker.
• If separate actuating mechanism is used to trip the circuit breaker then it requires separate mechanism to be built inside the circuit breaker to accept the plunger action of EL module and actuate the trip plate to trip the circuit breaker.

Thus, there is a need for an electronic trip circuit through which the two devices can be connected to the same one FSD. Also, that such devices can be connected without the need of ETU where some means of communication is required to trip the circuit breaker. Thereby resulting in no separate tripping device or actuation mechanism; and also saving of the space.

SUMMARY OF THE INVENTION

The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form as a prelude to a more detailed description of the invention presented later.

It is an object of the present invention to overcome the drawbacks of the prior art.

It is another object of the present invention to develop an electronic circuit where only one FSD is used to trip the circuit breaker in earth leakage module.

According to the present invention, the foregoing and other objects and advantages are attained by providing a trip circuit for earth leakage module comprising: 1. A trip circuit for earth leakage module (EL) comprising: a housing; a circuit breaker assembly in said housing for making and breaking an electrical connection comprising a connected a flux shift device (FSD) and Electronic trip unit (ETU);WHEREIN earth leakage module senses the leakage current to drive the 1st relay which disconnects the ETU’s connection to the FSD thereby driving the second relay connecting the FSD to the earth leakage module and tripping the circuit breaker.

In one implementation, the present invention provides a trip circuit for in earth leakage module (EL) comprising: a housing; a circuit breaker assembly in said housing for making and breaking an electrical connection comprising a connected a flux shift device (FSD) and Electronic trip unit (ETU);means for amplifying or switching electronic signals is a mosfet ; an earth leakage device connected with the ETU; a microcontroller for delaying the two relays; WHEREIN when ETU senses the fault and gives a trip command then mosfet M2 is turned on which is inside the ETU there by tripping the circuit breaker; and when EL module senses the fault, EL controller turns the port pin on thereby making the relay turn to open state, so that the FSD is disconnected from the ETU and then the EL controller makes the other port pin high, thereby turning the relay from open state to closed state and connecting the FSD to EL module and then controller makes another port pin high and mosfet M1 turns on thereby tripping the circuit breaker.

Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of instrumentalities and combinations particularly pointed out in the appended claims.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The above and other aspects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings in which:

Figure 1 illustrates a Block Diagram of Earth leakage module in conjunction with circuit breaker, in accordance with an embodiment of the present subject matter.

Figure 2 illustrates a Circuit Diagram of Trip circuit for Earth leakage module used in circuit breaker, in accordance with an embodiment of the present subject matter.

Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure. Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The following 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 and spirit of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.

The terms and words used in the following description and claims 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 as defined by the appended claims and their equivalents.

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.

Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.

It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

This present invention generally relates to a trip circuit used in earth leakage module wherein both the devices can work independently by connecting the FSD and when worked in conjunction the ETU in the circuit breaker is always connected to the FSD. Since ETU are powered using CT (Current transformers) the ground is floating and many earth leakage devices are powered directly from line supply. Hence both the connections of the ETU going to the FSD are required to be disconnected to have a safe operation. Thus the ETU in the circuit breaker is always connected to the FSD and when leakage current is sensed by the earth leakage devices it drives 1strelay which disconnects the ETU’s connection to the FSD thereby driving the 2ndrelay connecting the FSD to the earth leakage device and tripping the circuit breaker.

Moreover it be noted that in case of current transformer, CT the incoming side and the secondary side are completely isolated with the help of iron core. So the ground on the secondary side is a floating ground. In case of earth leakage devices the supply is taken directly from mains voltage so the ground in case of EL module is the neutral potential. So when FSD is triggered it is required that both the ground should be separate to avoid any catastrophic failure.

This invention uses an electronic circuit through which the two devices may be connected to the same FSD. By doing so in case of thermomagnetic circuit breakers such devices may be connected without the need of ETU where some means of communication is required to trip the circuit breaker.

The present invention provides two relays inside the earth leakage module. No separate tripping device or separate actuating mechanism is required to be built inside the trip unit. No extra space is required inside the breaker as it is built inside the EL module. It’s simple to use and doesn’t require to build an actuating mechanism.

Referring now to figure 1, shows a block diagram of earth leakage module in conjunction with circuit breaker. It shows that FSD has two terminals names as A1 and A2 which are connected to EL module and from EL module B1 and B2 terminals are connected to the ETU. When independently used like, say if only ETU is used then A1 and A2 terminals are directly connected to the ETU and if Earth leakage device is connected only with thermos-magnetic breaker then A1 and A2 are connected to the EL module without any connection from B1 and B2.

Referring now to figure 2, shows a circuit diagram of trip circuit in earth leakage module: The diagram shown is when earth leakage device is connected with the ETU. The diagram illustrates two cases.
Case 1: when ETU senses the Fault: Relay used in the circuit is a NC contact relay so the FSD is always connected to the ETU even if the Earth leakage device is not powered. Thus when ETU senses the fault and gives a trip command then mosfet M2 is turned on which is inside the ETU there by tripping the circuit breaker.
Case 2: EL module senses the fault: When EL module senses the fault, EL controller turns the port pin P1.3 on thereby making the relay turn On (From NC to NO/from closed state to open state).So the FSD is disconnected from the ETU. Now the EL controller makes the P1.2 high, thereby turning on the NO relay (From NO to NC/ from open state to closed state).Now the FSD is connected to EL module and then controller makes P1.1 high and mosfet turns on thereby tripping the circuit breaker.

In one implementation the present invention, provides a fail proof solution, as the two relays are used for acknowledgement i.e when the 1st relay opens up, the ETU is disconnected from the FSD and then after some time delay the microcontroller gives command to 2nd relay thereby connecting the FSD to the EL module. Thus, it is fail proof as never at a time two devices will be connected to FSD.

In one implementation the present invention, provides that both the devices may be used independently i.e when only ETU is used only then A1 terminal is connected to B1 and A2 is connected to B2. So the FSD is connected to ETU. Further, when EL module is used then A1 and A2 terminal is going to EL module and from EL two terminals will be coming and will connect to B1 and B2 terminal. And the internal construction is shown in figure 2.

Some of the important aspects of the present invention, are mentioned below:
• No separate actuating mechanism or shunt trip is required for earth leakage module.
• ETU can trip the breaker even if earth leakage device is not powered as the ETU is always connected to FSD seen in the diagram using an NC contact.
• Since two relays are used inside the earth leakage module, No separate tripping device or separate actuating mechanism is required to be built inside the trip unit.
• No extra space is required inside the breaker as it is built inside the EL module.
• It’s simple to use and doesn’t require to build an actuating mechanism.

The illustrations of arrangements described herein are intended to provide a general understanding of the structure of various embodiments, and they are not intended to serve as a complete description of all the elements and features of apparatus and systems that might make use of the structures described herein. Many other arrangements will be apparent to those of skill in the art upon reviewing the above description. Other arrangements may be utilized and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. Figures are also merely representational and may not be drawn to scale. Certain proportions thereof may be exaggerated, while others may be minimized. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.

Thus, although specific arrangements have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose may be substituted for the specific arrangement shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments and arrangements of the invention. Combinations of the above arrangements, and other arrangements not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description.