Claims:We claim:

1. A Rogowski coil current sensor, the Rogowski coil comprising:
a first C shaped insulated core having at least one protrusion configured on first end and at least one cut adapted on second end, the first C shaped core having coil wound thereon; and
a second C shaped insulated core having at least one cut adapted on first end and at least protrusion configured on the second end, the second C shaped insulated core having coil wound thereon,
wherein the first C shaped insulated core and the second C shaped insulated core are joined together to form a circular core and the coils are connected in series.

2. The Rogowski coil current sensor of claim 1, wherein the first C shaped insulated core and the second C shaped insulated core includes winding wound thereon.

3. The Rogowski coil as claimed in claim 1, wherein the at least one protrusion on the first end of the first C shaped insulated core gets inserted into the at least one cut adapted on the first end of the second C shaped insulated core and vice a versa, when the first C shaped insulated core and the second C shaped insulated core are joined together and wound cores overlaps each other to form a single assembly.

4. The Rogowski coil as claimed in claim 1, wherein the ends of the first C shaped insulated core and the second C shaped insulated core are stepped to give support to the windings.

5. The Rogowski coil as claimed in claim 1, wherein the first C shaped insulated core and the second C shaped insulated core are made exactly alike.

6. The Rogowski coil as claimed in claim 1, wherein shape and type of winding is decided based on accuracy requirement of the Rogowski.

7. The Rogowski coil as claimed in claim 1, wherein the first C shaped insulated core and the second C shaped insulated core are connected together with any one of multiple protrusions and cuts, wedge shaped means and dove tail arrangement.

8. The Rogowski coil as claimed in claim 1, wherein the wound coils of the first C shaped insulated core and the second C shaped insulated core are connected in series.

, Description:Field of the invention

The present invention relates to Rogowski coil current sensor, and more particularly to a split core Rogowski coil current sensor.

Background of the invention

The Rogowski coil is used as current sensor in various electrical equipment such as circuit breakers, transformers, electrical furnace and the like for measurement and protection purpose. The Rogowski coils work on Faraday’s law of electromagnetic induction. Faraday's law of Electromagnetic induction state that whenever a conductor is placed in a varying magnetic field emf is induced therein. The induced emf is equal to the rate of change of flux linkages (flux linkages is the product of turns, n of the coil and the flux associated with it). The associated flux is proportional to the current through the conductor.

The voltage that is induced in the Rogowski coil is proportional to the rate of change of current in the straight conductor. Further, the output of the Rogowski coil is usually connected to an electrical (or electronic) integrator circuit to provide an output signal that is proportional to the current. The Rogowski coil has following advantages over other types of current transformers.

Because, the Rogowski coil has no iron core to saturate, it is highly linear even when subjected to large currents, such as those used in electric power transmission, welding, or pulsed power applications. This linearity also enables a high-current Rogowski coil to be calibrated using much smaller reference currents.

Further, due to low inductance of the Rogowski coil, the Rogowski coil can respond to fast-changing currents, down to several nanoseconds and there is no danger of opening the secondary winding.

Conventional current transformers require an increase of the number of secondary turns, in order to keep the output current constant. Therefore, the Rogowski coil for large current is smaller than an equivalent rating current transformer.

In conventional Rogowski coils, the coils are wound over solid cores. In some cases, the coils are wound on pieces of cores the coils are connected on means like PCBto form close circuit loop. In some cases, the coils are wound over flexible core with arrangement of connecting the two ends with the help of additional components. The conventional Rogowski coil employs multiple components adopting complex processes for manufacturing.

Specifically, Chinese patent CN201638626U discloses a Rogowski coil having multi-core plastic components along joined together to form the desired shape. The multiple components are joined with pin.

Another US Patent 7579824 discloses uses a Printed circuit board for making a Rogowski coil.

Yet another US patent applications 20130063131 and 20140340072 discloses use multiple hollow bobbins with multiple connection arrangement to be used for energy meter application.

One more US patent application no. 20130187636 discloses a energy harvest split core design elements for ease of installation, high performance, and long term reliability. This uses a clamp for installing Rogowski on transmission lines.

The above disclosed Rogowski coil of the prior art uses complex method for manufacturing them.

Accordingly, there exists a need to provide a Rogowski coil current sensor, which overcomes abovementioned drawbacks.

Objects of the invention

An object of the present invention is to provide a Rogowski coil which is simple in construction.

Yet another object of the present invention is to provide the Rogowski coil which is manufactured using a simple process.

Summary of the invention

Accordingly, the present invention provides a Rogowski coil. The Rogowski coil comprises a first C shaped insulated core having at least one protrusion configured on first end and at least one cut adapted on second end. Further, the Rogowski coil comprises a second C shaped insulated core having at least one cut adapted on first end and at least protrusion configured on the second end. The first C shaped insulated core and the second C shaped insulated core includes coils wound thereon. Specifically, the first C shaped insulated core and the second C shaped insulated core are joined together to form a circular core and the coils are connected in series.

Brief description of the drawings

Figure 1, 2 and 3showsaRogowski coil and elements thereof, 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 embodiment.

The present invention provides Rogowski coil Rogowski coil current sensor. The Rogowski coil is simple in construction and is manufactured using a simple process.

The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures.

Referring to figure 1-3, there is shown a Rogowski coil current sensor, in accordance with the present invention. The Rogowski coil current sensor (100) (hereinafter the “Rogowski coil (100)”) includes afirst C shaped insulated core (10) and a second C shaped insulated core (20).In a preferred embodiment, the first C shaped insulated core (10) and the second C shaped insulated core (20) can be made exactly alike. The first C shaped insulated core (10) and the second C shaped insulated core (20) includes winding wound thereon.

The first C shaped insulated core (10) includes a first end (12) and a second end (14). The first end (12) includes at least one protrusion (12a) configured thereon and the second end (14) includes at least one cut/notch(14a) adapted thereon. The first C shaped core (10) also includes coil (16) wound thereon. In an embodiment, the first C shaped insulated core (10) is made up of flexible plastic material. In another embodiment, coil (16) is wound over the first C shaped insulated core (10) and then the first C shaped insulated core (10) is bent to form C shaped structure.

Further, the second C shaped insulated core (20) includes a first end (22) and a second end (24). The first end (22) includes at least one cut/notch (22a) adapted thereon and the second end (24) includes at least one protrusion (24a) configured thereon. The second C shaped core (20) also includes having coil (26) wound thereon. In an embodiment, the second C shaped insulated core (20) is made up of flexible plastic material. In another embodiment, coil (26) is wound over the first C shaped insulated core (20) and then the second C shaped insulated core (20) is bent to form C shaped structure.

Though, the protrusions and corresponding cuts are provided on ends of the first C shaped insulated core (10) and the second C shaped insulated core (20), it is evident to those skilled in the art that the first C shaped insulated core (10) and the second C shaped insulated core (20) are connected together with any one of multiple protrusions and cuts, wedge shaped means and dove tail arrangement configured on respective ends thereof.

The first C shaped insulated core (10) and the second C shaped insulated core (20) are joined together to form a circular core and the coils are connected in series. Specifically, thewound cores (10, 20) overlap each other to form a single assembly.

Specifically, the at least one protrusion (12a) on the first end (12) of the first C shaped insulated core (10) gets inserted into the at least one cut/notch (22a) adapted on the first end (22) of the second C shaped insulated core (20) when the first C shaped insulated core (10) and the second C shaped insulated core (20) are joined together. Similarly, at the same time the at least one protrusion (24a) of the second end (24) gets inserted into the at least one cut/notch (14a) of the second end (14) of the first C shaped insulated core (10) to form a single core of the Rogowski coil (100).

In an embodiment, the ends of first C shaped insulated core (10) and the second C shaped insulated core (20) are stepped to give support to the windings.

In another embodiment, the shape and type of winding can be decided based on accuracy requirement of the Rogowski coil (100). Further, the Rogowski coil (100) can be calibrated along the circuit in which the Rogowski coil will be used. The calibration can be done at various levels of currents.

Advantages of the invention

1. The Rogowski coil (100) is simple construction
2. The Rogowski coil (100) includes only two components viz. core and coil
3. The Rogowski (100) is made using two exact similar wound cores and as the winding is wound over C shaped core, the winding is relatively easier
4. The Rogowski coil (100) does not require extra components for connecting the ends of the core
5. The required accuracy of the Rogowski coil (100) output can be achieved by suitably calibrating the coil along with the circuit with which the coil will be used

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.