MODULAR MULTIFUNCTION METERING UNIT FOR HIGHER ISOLATION AND UNIVERSAL CURRENT TRANSFORMER (CT) TERMINATION

FIELD OF THE INVENTION

This invention relates compactness and modularity of the metering unit with ease of maintenance. The present invention specifically relates to a modular multifunction metering unit for providing various types of connectivity for input current termination by extracting the highest performance of CT and also higher isolation in much compact construction.

BACKGROUND OF THE INVENTION

Current-Transformers (CT) are mounted on board and used in metering units to detect input current. The CTs are arranged with primary terminals (two terminals per CT) connected to input current and two secondary terminals terminated on PCB board for processing. In existing meters, minimum two terminals per CT are required on terminal blocks of meter, and input current (from external source) wire is to be stripped, crimped and terminated on terminal blocks (external side of meter).

Further, only one type of termination such as U, Ring type termination, etc, can usually be used, and input current wire passing through the CTs are of fixed amps and thus only specific amps wire can be terminated on the meter. The accuracy of existing setup is not consistent, because the input current wire is not always centered to the CTs and so not producing a uniform magnetic flux in CT coils. In existing meters, only pass through or terminal type is possible for input current wire but not both. In pass through and terminal types of the existing meters, all wires connected to meters (including input current wires, input voltage
wires, auxiliary voltage wires, communication wires, etc) are to be removed during maintenance of meters.

In general, hardware design of these meters requires certain isolation (creepage and clearance) between various electronics component leads to maintain certain safety requirements. Thus, it is very difficult to achieve optimum clearance and creepage for better isolation without increasing size of PCB boards. In the existing meters, if the meters have to be taken for service / maintenance, then all the terminations have to be removed. This requires a powers shutdown and it is a time consuming process. Therefore, it is desirable to provide a modular multifunction metering unit for higher isolation and universal CT termination, which is capable of overcoming the aforementioned drawbacks.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a modular multifunction metering unit, which provides universal CT termination and improves performance of current transformers.

Another object of the present invention is to provide a modular multifunction metering unit, which provides enough safety margins inside the power supply modules with optimum clearance and creepage for better isolation without increasing size of power supply modules.

According to one aspect, the present invention, which achieves the objectives, relates to a modular metering unit, comprising a meter block assembled with a set of openings and a set of plug-in connectors. A terminal block comprises one or more current transformer (CT) blocks each consisting of a current carrying conductor that is concentrically surrounded by a current transformer to form uniform distribution of magnetic field around the current transformer, and one or more connecter blocks, each arranged with a connector that is configured to interconnect with terminal wires. Each current transformer of the CT blocks is introduced into the appropriate openings of the meter block and each connector of the connecter blocks is interconnected to the appropriate plug-in connectors of the meter block, such that the CT blocks and the connecter blocks are detachably connected to the meter block. Such metering unit provides universal CT termination and improves performance of current transformers. It also provides enough safety margins inside the power supply modules with optimum clearance and creepage for better isolation without increasing size of power supply modules.

Furthermore, the current carrying conductor whose ends are exposed from the current transformer, so that current wires are electrically connected at both ends of the current carrying conductor through a wire connector, which is configured as Pin type connector, U lug/ring connector or hollow pass through connector. The current carrying conductor is designed to fasten with the U lug/ring connector or Pin type connector using screws. Similarly, the current carrying conductor is designed as hollow pass through connector, such that the current wires concentrically pass through the current transformer. Each plug-in connector of the meter block is configured with a set of connector ribs that is placed and positioned between a set of connector leads in such a way that the height of each connector rib is defined higher than the height of each connector lead. In addition, the meter block comprises a meter block component with a set of component ribs that is placed and positioned between a set of component leads in such a way that the height of each component rib is defined higher than the height of each component lead.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exploded view of a modular multifunction metering unit, in accordance with an exemplary embodiment of the present invention;

FIG. 2 illustrates an assembled view of the modular multifunction metering unit, in accordance with an exemplary embodiment of the present invention;

FIG. 3 illustrates a detailed and cut view of current terminal (CT) blocks of the modular multifunction metering unit, in accordance with an exemplary embodiment of the present invention;

FIG. 4 illustrates a partial cut view of the current terminal (CT) blocks assembled in the modular multifunction metering unit, in accordance with an exemplary embodiment of the present invention;

FIG. 5 illustrates a schematic view of the modular multifunction metering unit, in accordance with another exemplary embodiment of the present invention;

FIG. 6 illustrates a schematic view of the modular multifunction metering unit, in accordance with a further exemplary embodiment of the present invention;

FIG. 7 illustrates a schematic view of connector blocks of the modular multifunction metering unit, in accordance with an exemplary embodiment of the present invention;

FIG. 8 illustrates a schematic view of back panel arrangement of a meter block of the modular multifunction metering unit, in accordance with an exemplary embodiment of the present invention; and

FIG. 9 illustrates a detailed view of a meter block component of the modular multifunction metering unit, in accordance with an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be described herein below with reference to the accompanying drawings.

Referring to FIG. 1, an exploded view of a modular multifunction metering unit is illustrated, in accordance with an exemplary embodiment of the present invention. A modular multifunction metering unit comprises a meter block (10) and a terminal block (20) that is composed of one or more current terminal (CT) blocks (30) and one or more connector blocks (40). The connector blocks (40) are configured as, but not limited to voltage blocks, auxiliary blocks, communication blocks and terminal blocks. The meter block (10) is associated with one or more electrical loads for measuring amount of electrical energy comsumed by the electrical loads. The meter block (10) is assembled with a set of openings (10a) and a set of plug-in connectors (12) provided in its back panel (11) for receiving the CT blocks (30) and the connector blocks (40) of the terminal block (20). The meter block (10) is specifically designed in such a way that it can be detachably connected to the CT blocks (30) and the connector blocks (40) of the terminal block (10), as shown in FIG. 2, which illustrates an assembled view of the modular multifunction metering unit, in accordance with an exemplary embodiment of the present invention. Thus, it facilitates portability of the meter block (10) and interfacing of the meter block (10) with multiple terminal blocks (20).

FIG. 3 illustrates a detailed and cut view of the current terminal (CT) blocks (30) of the modular multifunction metering unit, in accordance with an exemplary embodiment of the present invention. Each CT block (30) is assembled with a current carrying conductor (31) and a current transformer (CT) (32). The current carrying conductor (31) is partially and concentrically surrounded by the current transformer (32) in such a way that uniform distribution of magnetic field is formed around the current transformer (32). The current transformer (32) is partially inserted into the openings (10a) of the meter block (10) to electrically connect the CT blocks (30) to the meter block (10), as shown in FIG. 4, which illustrates a partial cut view of the current terminal (CT) blocks (30) assembled in the modular multifunction metering unit, in accordance with an exemplary embodiment of the present invention.

Further, the current carrying conductor (31) whose ends are exposed from the current transformer (32), so that current wires (50a) are electrically connected at both ends of the current carrying conductor (31) through a wire connector (33). The metering unit can accommodate any type of wire connectors (33), which include, but are not limited to U lug/ring connector (33a) or Pin type connector (33b). The metering unit is configured with a unique way of terminating current wires (50a) on the CT block (30) irrespective of type of lugs (33) and also has pass through structure (33c) on same construction. The metering unit has an ability to terminate the current wires (50a) above 2.5 sq.mm, which facilitates higher current carrying wires leading to flexibility to the user. In case of U lug or ring connector (33a), the current carrying conductor (31) of the CT block (30) is fastened to the U lug or ring connector (33a) connected with the current wires (50a), by means of tightening screws (60a) in the threaded holes provided at both ends of the current carrying conductor (31), as shown in FIG. 4.

Similarly, in case of Pin type connector (33b), the current carrying conductor (31) of the CT block (30) is electrically connected to the current wires (50a) by tightening screws (60b) against the current wires (50a) after inserting the current wires (50a) into holes provided at both ends of the current carrying conductor (31), as shown in FIG. 5, which illustrates a schematic view of the modular multifunction metering unit, in accordance with another exemplary embodiment of the present invention. Further, the current carrying conductor (31) of the CT block (30) can be designed as hollow pass through structure (33c) on the same construction of the metering unit, which enables the user to directly pass the current wires (50a) concentrically through the current transformer (32), as shown in FIG. 6, which illustrates a schematic view of the modular multifunction metering unit, in accordance with a further exemplary embodiment of the present invention. Such arrangement of metering unit eliminates the use of external current transformer for low load applications.

Referring to FIG. 7, a schematic view of the connector blocks (40) of the modular multifunction metering unit, in accordance with an exemplary embodiment of the present invention. Each connector block (40) is arranged with a connector (41) associated with terminal wires (50b) that are configured as voltage wires, auxiliary wires, communication wires and terminal wires. The connector (41) of each connector block (40) is inserted/plugged into the plug-in connector (12) of the meter block (10), i.e. connectors (12, 41) of the meter block (10) and the connector block (41) are interconnected together. The plug-in connector (12) of the meter block (10) has a set of connector ribs (12b) placed and positioned between connector leads (12a), where the height of each rib (12b) is optimized, i.e. height of the connector ribs (12b) is defined higher than height of the connector leads (12a), which provides higher isolation for the same pitch of connectors (12, 41).

Referring to FIG. 8, a schematic view of back panel arrangement of the meter block (10) of the modular multifunction metering unit is illustrated, in accordance with an exemplary embodiment of the present invention. The meter block (10) comprises a meter block component (13) that is attached in the back panel (11) of the meter block (10). The meter block component (13) has a set of component ribs (13b) placed and positioned between component leads (13a), where the height of each component rib (13b) is optimized for higher creepage and clearance on PCB boards, as shown in FIG. 9, which illustrates a detailed view of the meter block component (13) of the modular multifunction metering unit, in accordance with an exemplary embodiment of the present invention. In particular, the height of each component rib (13b) is defined higher than height of the component leads (13a), which achieves the higher isolation at lower cost due to compact construction.

The metering unit is specifically designed and assembled with the detachable meter block (10) from the terminal block (20), which results in easy maintenance and thus saves cost and time. It specifically provides universal CT termination and improves performance of current transformers. It also provides enough safety margins inside the power supply modules with optimum clearance and creepage for better isolation without increasing size of power supply modules. Moreover, it provides uniform distribution of magnetic flux due the current carrying conductor (31) being concentric with the current transformer (31), which leads to better accuracy and performance of the metering unit. Further, it is applicable for Digital Multi Function Meters and for any devices with high voltage power supply module and looking for higher isolation inside hardware design.

The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration only. It is evident to those skilled in the art that although the invention herein is described in terms of specific embodiments thereof, there exist numerous alternatives, modifications and variations of the invention. It is intended that all such modifications and alterations be included insofar as they come within the spirit and scope of the invention as claimed or the equivalents thereof. Hence all variations, modifications and alternatives that falls within the broad scope of the appended claims comes under the gamut of the invention.

WE CLAIM:

1. A modular metering unit, comprising:

a meter block assembled with a plurality of openings and a plurality of plug-in connectors; and

a terminal block comprising:

one or more current transformer (CT) blocks, each composed of a current carrying conductor that is concentrically surrounded by a current transformer to form uniform distribution of magnetic field around the current transformer; and

one or more connecter blocks, each arranged with a connector that is configured to interconnect with terminal wires,

wherein each current transformer of said CT blocks is introduced into the appropriate openings of said meter block and each connector of said connecter blocks is interconnected to the appropriate plug-in connectors of said meter block, such that said CT blocks and said connecter blocks are detachably connected to said meter block.

2. The modular metering unit as claimed in claim 1, wherein said current carrying conductor whose ends are exposed from said current transformer, so that current wires are electrically connected at both ends of said current carrying conductor through a wire connector.

3. The modular metering unit as claimed in claim 2, wherein the wire connector is configured as Pin type connector, U lug/ring connector or hollow pass through connector.

4. The modular metering unit as claimed in claims 1-3, wherein said current carrying conductor is designed to fasten with said U lug/ring connector or Pin type connector using screws.

5. The modular metering unit as claimed in claims 1-3, wherein said current carrying conductor is designed as hollow pass through connector, such that the current wires concentrically pass through said current transformer.

6. The modular metering unit as claimed in claim 1, wherein each plug-in connector of said meter block is configured with a plurality of connector ribs that is placed and positioned between a plurality of connector leads in such a way that the height of each connector rib is defined higher than the height of each connector lead.

7. The modular metering unit as claimed in claim 1, wherein said meter block comprises a meter block component with a plurality of component ribs that is placed and positioned between a plurality of component leads in such a way that the height of each component rib is defined higher than the height of each component lead.