DESC:TRANSFORMER FOR 3-PHASE ELECTRIC LOCOMOTIVE
TECHNICAL FIELD
The present disclosure relates generally to a transformer, and more specifically, to a transformer with a steel tank for supplying power to a 3-phase electric locomotive.
BACKGROUND
A transformer is a static device transforming power from one circuit to another circuit at same frequency but having different characteristics. These circuits are conductively disjointed but magnetically coupled by a common time varying magnetic field. It can raise or lower voltage with a corresponding decrease or increase in current.
In all electric locomotives, limiting the value of current during starting and speed control is achieved by supply of variable voltages to traction motors. This variation of applied voltage can be carried out easily by the use of transformer along with static converters provided in the locomotives.
Conventionally, each locomotive requires a transformer for feeding supply to traction converters / traction motors, to auxiliary converters for supplying to auxiliary machines, and to supply any other loads of the locomotive. Such transformers include various windings according to required loads/currents/voltages and other such operational and functional requirements. These windings include primary including HV windings and secondary windings including traction windings, and auxiliary or bur windings etc. Additionally, the windings include a filter winding connected on locomotive to passive filter.
These transformers traditionally include a transformer tank housing the main transformer, and a cover assembly. These transformer tanks additionally house various chokes including series resonant and auxiliary converter chokes. The transformer tank and the cover assembly of these locomotive transformers are normally designed with aluminium alloys. The aluminium alloys are expensive with limited supply and thus the transformer tanks have become a bottle neck in manufacturing of locomotive transformers both due to higher cost and limited number of global suppliers.
However, the reason for using expensive aluminium or its alloys as a material for the manufacturing of the transformer tank is primarily related to operational problems associated with any other iron based alloy including steel. The operational problems include overheating of such transformer tanks due to high magnetic flux and tank stray losses due to radial flux linkage with tank walls. These problems affect the proper and efficient working of any transformer tank made of any iron based alloy or any other magnetically induced/affected alloy.
Moreover, existing windings of these aluminium tank transformer are conventionally designed with a sandwich type construction of the HV, traction, bur, and the filter windings assembled around a column type transformer core. Furthermore, all different windings have the same diameter and the axial heights vary. In these arrangements, windings with high current ratings (e.g. traction windings) are positioned closer to the transformer tank. This further aggravates the heating and stray losses if the tank is made of any material capable of being magnetically induced or affected.
Therefore, there is a need for a more cost and energy efficient transformer for electric locomotives.
SUMMARY
The present disclosure seeks to provide a transformer with a steel tank for a 3-phase electric locomotive.
In one aspect, embodiments of the present disclosure provide a transformer with a steel tank for feeding power and auxiliary loads of a 3-phase electric locomotive. In an embodiment, the transformer with the steel tank includes a single phase. The transformer with the steel tank includes a steel tank, a transformer core, and a winding assembly. The steel tank houses the transformer core, the winding assembly, and other components of the transformer with the steel tank. In an embodiment, the transformer with the steel tank includes a steel cover to cover the steel tank. In yet another embodiment, the steel tank and the steel cover are made of standard steel.
The winding assembly includes a first winding, a second winding, a third winding, and a fourth winding. The first, second, third, and the fourth windings are concentrically mounted around the transformer core. In an embodiment, the transformer core is a column type core. In yet another embodiment, the first winding is an auxiliary winding, the second winding is a high current winding and includes four traction windings, the third winding is filter winding, and the fourth winding is a high voltage (HV) winding.
In an embodiment, the high current windings are mounted close to the transformer core than to the steel tank. In another embodiment of the present disclosure, the HV and the four traction windings are mounted concentrically, and the filter windings are positioned in between the HV and the traction windings, and the auxiliary windings are positioned prior to the traction windings.
In an embodiment, the transformer with the steel tank feeds a GTO (gate turn-off thyristor) or an IGBT (insulated gate bipolar transistor) based power and auxiliary load. In yet another embodiment, the transformer with the steel tank is mounted under frame of the 3-phase electric locomotive.
It will be appreciated that features of the present disclosure are susceptible to being combined in various combinations without departing from the scope of the present disclosure.
BRIEF DESCRIPTION OF THE FIGURES
The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, example constructions of the disclosure are shown in the drawings. However, the present disclosure is not limited to specific methods and instrumentalities disclosed herein. Moreover, those in the art will understand that the drawings are not to scale. Wherever possible, like elements have been indicated by identical numbers.
Embodiments of the present disclosure will now be described, by way of example only, with reference to the following diagrams wherein:
Fig. 1 is a perspective view of a transformer with steel tank for a 3-phase electric locomotive, in accordance with an embodiment of the present disclosure;
Fig. 2 is a schematic illustration of a transformer core of the transformer with steel tank, in accordance with an embodiment of the present disclosure;
Fig. 3 is a cross-sectional view of a winding assembly mounted around the transformer core, in accordance with another embodiment of the present disclosure.
In the accompanying drawings, an underlined number is employed to represent an item over which the underlined number is positioned or an item to which the underlined number is adjacent. A non-underlined number relates to an item identified by a line linking the non-underlined number to the item. When a number is non-underlined and accompanied by an associated arrow, the non-underlined number is used to identify a general item at which the arrow is pointing.
DETAILED DESCRIPTION OF EMBODIMENTS
The following detailed description illustrates embodiments of the present disclosure and manners by which they can be implemented. Although the best mode of carrying out the present disclosure has been disclosed, those skilled in the art would recognize that other embodiments for carrying out or practicing the present disclosure are also possible.
In one aspect, embodiments of the present disclosure provide a transformer with a steel tank for a 3-phase electric locomotive. In some aspects, the transformer with the steel tank feeds power and auxiliary loads of the 3-phase electric locomotive. The transformer with the steel tank includes a steel tank, a transformer core, and a winding assembly. The transformer core is housed within the steel tank.
The winding assembly includes a first winding, a second winding, a third winding, and a fourth winding. The transformer with the steel tank is characterized in that the first, second, third, and the fourth windings are concentrically mounted around the transformer core.
Embodiments of the present disclosure substantially eliminate, or at least partially address, problems in the prior art, and assists the locomotive manufacturers, consumers and suppliers.
Referring now to drawings, particularly by their reference numbers, Fig. 1 is a perspective view of a transformer with a steel tank 100 for a 3-phase electric locomotive (not shown), in accordance with an embodiment of the present disclosure. The transformer with the steel tank 100 includes a steel tank 102 and a steel cover 104. The steel cover 104 is configured to cover the steel tank 102. The steel cover 104 includes electrical connections 106 placed on top. The electrical connections 106 of the transformer with the steel tank 100 are configured to feed a GTO or an IGBT based power or auxiliary load of the 3-phase electric locomotive.
In an embodiment of the present disclosure, the steel tank 102 and the steel cover 104 are made of standard or mild steel conforming to S355J2N or its equivalent IS. The transformer with the steel tank 100 further includes a fixing plate 108 coupled with the steel tank 102. The fixing plate 108 is configured to be used for mounting the transformer with the steel tank 100 under a frame (not shown) of the 3-phase electric locomotive. In an embodiment, the transformer with the steel tank 100 is oil cooled via forced cooling.
Fig. 1 is merely an example. A person skilled in the art will recognize many variations, alternatives, and modifications of embodiments of the present disclosure.
Fig. 2 is a schematic illustration of a transformer core 200, in accordance with an embodiment of the present disclosure. The transformer core 200 is configured to be housed within the steel tank 102 of the Fig. 1. In an embodiment of the Fig. 2, the transformer core 200 is a column type core.
Fig. 2 is merely an example. A person skilled in the art will recognize many variations, alternatives, and modifications of embodiments of the present disclosure.
Fig. 3 is a cross-sectional top view of the transformer core coil assembly, in accordance with the embodiments of the present disclosure. As shown, the column type transformer core coil assembly are cut horizontally to provide a clear view.
As illustrated, a winding assembly 300 is mounted around the column type transformer core 200 of the transformer with the steel tank 100. Although, the winding assembly 300 is described with only one arrangement around the column type transformer core 200, it may be contemplated that other arrangements of the winding assembly 300 is possible without departing from scope of the present disclosure.
The winding assembly 300 comprises a first winding 302, a second winding 304, a third winding 306, and a fourth winding 308 wound around the column type transformer core 200. In embodiments of the present disclosure, the fourth winding 308 constitutes primary winding and the first, second, and the third windings (302, 304 & 306) together constitute secondary winding of the winding assembly 300.
The first winding 302 is an auxiliary or BUR winding. The first winding 302 supplies power to auxiliary machines (not shown) of the 3-phase electric locomotive. In an embodiment, the first winding 302 is configured to conform to power ratings of 334 kVA, voltage ratings of 1000 Volts, and current ratings of 334 Amps.
In an embodiment, the second winding 304 includes four traction windings (not shown) and is configured to supply power to traction converters (not shown) or traction motors (not shown) of the 3-phase electric locomotive. In another embodiment, the four traction windings are configured to conform to power ratings of 1449 kVA, voltage ratings of 1269 Volts, and the current ratings of 1142 Amps, for each individual traction windings. Moreover, the second winding 304 is a high current winding due to above ratings in all embodiments of the present disclosure.
Furthermore, the third winding 306 is a filter winding. In an embodiment, the third winding 306 is configured to be connected on the 3-phase electric locomotive to passive filter (not shown). The third winding 306 is configured to power ratings of 400 kVA, voltage rating of 1154 Volts, and a current rating of 347 Amps according to embodiments of the present disclosure.
The fourth winding 308 is a high voltage (hereinafter alternatively referred as HV) winding. In an embodiment, the fourth winding 308 or the HV winding 308 is configured to conform to ratings of 6531 kVA for power, 25000 Volts for voltage, and 261.25 Amps for current.
In an embodiment of the present disclosure, the winding assembly 300 is characterized in that the first winding 302, the second winding 304, the third winding 306, and the fourth winding 308 are concentrically mounted around the transformer core 200. As illustrated, the first and the second windings (302, 304) are mounted concentrically close to the transformer core 200 than the third and the fourth windings (306, 308). In other words, the first and the second windings (302, 304) are distant to the steel tank 102 of the Fig. 1 than the third and the fourth windings (306, 308).
In an embodiment of the present disclosure, the HV winding (i.e. the fourth winding 308) and the traction winding including the four traction windings (i.e. the second winding 304) are mounted concentrically around the transformer core 200. Further, the filter windings (i.e. the third winding 306) are positioned in between the HV (the fourth winding 308) and the traction windings (the second winding 304). Furthermore, the auxiliary windings (i.e. the first winding 302) are positioned prior to the traction windings (second winding 304).
In another embodiment of the present disclosure, the high current windings are mounted close to the transformer core 200 than to the steel tank 102. The second winding 304 being a high current winding is mounted close to the transformer core 200 than to the steel tank 102.
The above illustrated and described embodiments of the arrangements of the winding assembly 300 around the transformer core 200 result in very low heating of walls of the steel tank 102. These arrangements also control flux linkages with materials capable of being magnetically induced or affected, thereby controlling tank stray losses for the steel tank 102.
Fig. 3 is merely an example, which should not unduly limit the scope of the disclosure herein. A person skilled in the art will recognize many variations, alternatives, and modifications of embodiments of the present disclosure.
Embodiments of the present disclosure can be used for various purposes, including, though not limited to, manufacturing transformers for locomotives.
Embodiments of the present disclosure are described the transformer with a steel tank for 3-phase electric locomotive, wherein the transformer core is a column-type. However, a person ordinarily skilled in the art would appreciate that, the present disclosure works well for the column-type transformer core having single core or multiple cores.
Modifications to embodiments of the present disclosure described in the foregoing are possible without departing from the scope of the present disclosure as defined by the accompanying claims. Expressions such as “including”, “comprising”, “incorporating”, “consisting of”, “have”, “is” used to describe and claim the present disclosure are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural.
,CLAIMS:We claim:
1 A transformer with a steel tank for 3-phase electric locomotive comprising:
- a transformer core housed within the steel tank; and
- a winding assembly including a first winding, a second winding, a third winding and a fourth winding,
wherein the first winding, the second winding, the third winding and the fourth winding are concentrically mounted around the transformer core, and wherein the third winding is positioned between the second and fourth winding and the first winding is positioned before the second winding.
2 The transformer with the steel tank for the 3-phase electric locomotive of claim 1, wherein the transformer core is a column-type.
3 The transformer with the steel tank for the 3-phase electric locomotive of claim 1, wherein the winding assembly is mounted around the column-type transformer core.
4 The transformer with the steel tank for the 3-phase electric locomotive of claim 1, wherein the first winding is an auxiliary winding configured to supply power to auxiliary machines.
5 The transformer with the steel tank for the 3-phase electric locomotive of claim 1, wherein the second winding is a high current winding configured to supply power to traction convertors or traction motors, and wherein the second winding includes four traction windings.
6 The transformer with the steel tank for the 3-phase electric locomotive of claim 1, wherein the third winding is a filter winding configured to be connected on the 3-phase electric locomotive to a passive filter.
7 The transformer with the steel tank for the 3-phase electric locomotive of claim 1, wherein the fourth winding is a high voltage winding.
8 The transformer with the steel tank for the 3-phase electric locomotive of claim 1 further comprising a steel cover configured to cover the steel tank.
9 The transformer with the steel tank for the 3-phase electric locomotive of claim 1 further comprising a fixing plate coupled to the steel tank.