FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
As amended by the Patents (Amendment) Act, 2005
&
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2006
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
A core-type transformer with axially placed asymmetric secondary windings
APPLICANTS:
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company
INVENTORS:
Boyd Daniel, Ziomek Waldemar, Vijayan Krishnamurthy of CG Power Systems Canada Inc., 101 Rockman Street, Winnipeg, Manitoba R3T 0L7, Canada; all Canadian Nationals.
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the nature of this invention and the manner in which it is to be performed.

FIELD OF THE INVENTION:
This invention relates to the field of electronic and electrical equipment.
Particularly, this invention relates to power transformers.
Specifically, this invention relates to a core-type transformer with axially placed asymmetric secondary windings.
BACKGROUND OF THE INVENTION:
A Transformer is an electrical device that transfers energy from one circuit to another by magnetic coupling without any moving parts. It works on the Principle of Faradays Law of Electromagnetic Induction together with other laws of electricity. When a magnetic flux linked with an electric circuit varies, an electro motive force (voltage) is generated in the electric circuit, proportional to the rate of variation of flux with time.
The basic functional components of the transformer are a core made of magnetic material, a primary winding, and a secondary winding. The primary winding is connected to a source of an alternating current and the secondary winding is connected to the load. As the alternating current flows through the primary winding, the change in current in the primary windings creates a time-varying magnetic flux in the core, which induces a voltage in the secondary windings.

There is insulation medium between the windings and the windings and core of the transformer which forms the core coil assembly of the transformer. This insulation is mineral oil.
There is a need for three circuit core type transformers, typically in power transformer applications, where customer needs two secondary windings to supply load at two different voltages. Since the two secondary loads will be connected to different systems, they may require different power ratings and also may require different impedances with respect to HV winding and also different vector relationship with HV winding.
The deficiencies, in the prior art, are the following:
1. The impedance parameters required were not achievable by traditional winding configurations.
2. Traditional axially placed secondary winding type designs require identical secondary windings
Hence, there is a need for a transformer which obviates the limitations of the prior art.
OBJECTS OF THE INVENTION:
An object of the invention is to provide a three circuit core-type power transformer with axially placed asymmetric secondary windings of unequal power rating and differing vector groups.

Another object of the invention is to provide a transformer in which different impedance parameters between primary and secondary windings can be achieved.
SUMMARY OF THE INVENTION:
According to this invention, there is provided a core-type transformer with axially placed asymmetric secondary windings, said transformer comprises:
- axially placed secondary windings, each of said secondary windings further comprising 2 layers, each winding being of different axial height.
Typically, each of said windings is designed for different loads.
Typically, said transformer comprises a common primary winding radially placed outside said secondary windings.
Typically, said transformer comprises two Low Voltage (LV) windings, of 3 phases, being connected differently to achieve different vector relationship with respect to High Voltage (HV) windings.
Typically, said transformer comprising a low voltage first layer assembly of windings, said low voltage first layer assembly of windings further comprising a first layer of a low voltage winding situated axially on top and a first layer of a low voltage winding situated axially on bottom.
Typically, said transformer comprising a low voltage second layer assembly of windings, said low voltage second layer assembly of windings further comprising

a second layer of a low voltage winding situated axially on top and a second layer of a low voltage winding situated axially on bottom.
Typically, said transformer comprising a high voltage layer assembly of windings, said high voltage layer assembly of windings further comprising a high voltage winding situated axially on top) and a high voltage winding situated axially on bottom.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
The invention will now be described in relation to the accompanying drawings, in which:
Figure 1 illustrates a name plate drawing of the developed transformer;
Figure 2 illustrates a block diagram of the core-type transformer with axially placed asymmetric secondary windings;
Figure 3 illustrates a LVX winding and LVY winding connection diagram; and
Figure 4 illustrates a section view of the low voltage windings and the high voltage windings.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
According to this invention, a new type of core-type transformer with axially placed asymmetric secondary windings has been successfully developed.

Figure 1 illustrates a name plate drawing of the developed transformer.
Figure 2 illustrates a block diagram of the core-type transformer with axially placed asymmetric secondary windings.
Figure 3 illustrates a LVX winding and LVY winding connection diagram.
Figure 4 illustrates a section view of the low voltage windings and the high voltage windings.
In accordance with an embodiment of this invention, there is provided a low voltage (LV-1) first layer assembly of windings. This comprises the first layer of the low voltage winding situated axially on top (LVX-1) and the first layer of the low voltage winding situated axially on the bottom (LVY-1).
In accordance with another embodiment of this invention, there is provided a low voltage (LV-2) second layer assembly of windings. This comprises the second layer of the low voltage winding situated axially on top (LVX-1) and the second layer of the low voltage winding situated axially on the bottom (LVY-1).
In accordance with yet another embodiment of this invention there is provided a high voltage (HV) layer assembly of windings. This comprises a high voltage winding situated axially on top (HV-T) and a high voltage winding situated axially on the bottom (HV-T).
There are three legs of the windings in the transformer (Figure 3 of the accompanying drawings). A first leg (LI) includes a low voltage (LV-1) first layer

assembly of windings along with a low voltage (LV-2) second layer assembly of windings. Similarly, a second leg (L2) includes a low voltage (LV-1) first layer assembly of windings along with a low voltage (LV-2) second layer assembly of windings. Similarly, a third leg (L3) includes a low voltage (LV-1) first layer assembly of windings along with a low voltage (LV-2) second layer assembly of windings.
The windings are of unequal power ratings and have differing vector groups. The windings are enveloped in a core of the transformer. This provides a three circuit core-type power transformer with axially placed asymmetric secondary windings. It responds to demands for different loads, different impedance and different vector relationship.
The inventive step lies in provisioning a core-type power transformer with axially placed asymmetric secondary windings such that it is not limited by the need for identical secondary windings.
While this detailed description has disclosed certain specific embodiments of the present invention for illustrative purposes, various modifications will be apparent to those skilled in the art which do not constitute departures from the spirit and scope of the invention as defined in the following claims, and it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

We claim,
1. A core-type transformer with axially placed asymmetric secondary
windings, said transformer comprising:
- axially placed secondary windings, each of said secondary windings further comprising 2 layers, each winding being of different axial height.
2. The transformer as claimed in claim 1 wherein, each of said windings being designed for different loads.
3. The transformer as claimed in claim 1 wherein, said transformer comprising a common primary winding radially placed outside said secondary windings.
4. The transformer as claimed in claim 1 wherein, said transformer comprising two Low Voltage (LV) windings, of 3 phases, being connected differently to achieve different vector relationship with respect to High Voltage (HV) windings.
5. The transformer as claimed in claim 1 wherein, said transformer comprising a low voltage first layer assembly of windings, said low voltage first layer assembly of windings further comprising a first layer of a low voltage winding situated axially on top and a first layer of a low voltage winding situated axially on bottom.
6. The transformer as claimed in claim 1 wherein, said transformer comprising a low voltage second layer assembly of windings, said low voltage second layer assembly of windings further comprising a second layer of a low

voltage winding situated axially on top and a second layer of a low voltage winding situated axially on bottom.
7. The transformer as claimed in claim 1 wherein, said transformer comprising a high voltage layer assembly of windings, said high voltage layer assembly of windings further comprising a high voltage winding situated axially on top) and a high voltage winding situated axially on bottom.