Title of Invention	A METHOD FOR FEEDING HOTEL LOAD IN A TRAIN BY TAP CHANGER CONTROLLED LOCOMOTIVE TRANSFORMERS
Abstract	The regulating transformer (R) which draws power at 25 KV from the traction overhead line is divided into 32 parts that corresponds to 32 voltage steps. The output of the regulating transformer is fed to main transformer (M) which has an arrangement of one primary winding (P1, P2) and two secondary winding (S1, S"1 and S2, S"2). A single magnetic circuit is arranged for both the transformers (R) and (M). The flux of the Main transformer changes with change of tappings. But the magnetic flux (ΦR) in the regulating transformer (R) remains constant which generates additional voltage source for the Hotel load winding. Owing to the constant flux this voltage constant at all the speed (tap position) of the train. This voltage output is converted to D C by means of rectifiers and this D C power is utilized to meet the hotel load requirements.

Title of Invention

A METHOD FOR FEEDING HOTEL LOAD IN A TRAIN BY TAP CHANGER CONTROLLED LOCOMOTIVE TRANSFORMERS

Abstract

The regulating transformer (R) which draws power at 25 KV from the traction overhead line is divided into 32 parts that corresponds to 32 voltage steps. The output of the regulating transformer is fed to main transformer (M) which has an arrangement of one primary winding (P1, P2) and two secondary winding (S1, S"1 and S2, S"2). A single magnetic circuit is arranged for both the transformers (R) and (M). The flux of the Main transformer changes with change of tappings. But the magnetic flux (ΦR) in the regulating transformer (R) remains constant which generates additional voltage source for the Hotel load winding. Owing to the constant flux this voltage constant at all the speed (tap position) of the train. This voltage output is converted to D C by means of rectifiers and this D C power is utilized to meet the hotel load requirements.

Full Text	FIELD OF INVENTION The invention relates to a method for feeding hotel load in a train by tap changer controlled locomotive transformers. More particularly the invention relates to a method for feeding hotel load in a train by tap changer controlled locomotive transformers. Controlled locomotive transformers that replaces an existing diesel generator set capsule used for hotel load by an electrical system. BACKGROUND OF THE INVENTION In a conventional D.C. locomotive, a diesel generator set capsule is provided to feed the lighting, fan and catering load which are collectively known as "hotel load" in a train which is a requirement besides catering to the traction load. Owing to use of diesel, the environment becomes hazardous and the maintenance cost is high. There exist also chances of fire hazards. The space occupied by the whole set up is huge. Cost of running the set is also very high. For a run of 15 hours, to cater for a "hotel load" of 500KVA around 2000 litre diesel is consumed. Because of the Generator Set and its accessories, the temperature inside the locomotive is as high as 55°C. Accordingly, there exists a need to overcome the disadvantages of prior art. The present invention replaces the use of diesel by electricity for the purpose of catering to hotel load. This use of electricity increases the efficiency of the locomotive and provides a cleaner environment. This also reduces the maintenance cost of the locomotive and chances of fire hazard inside the locomotive is reduced due to elimination of the diesel requirement of the Gen-Set Capsule required for Hotel load. The use of electricity also results in the reduction of the ambient temperature due to reduction in exhaust gas of the locomotive. This invention also relates to generating more free space inside the locomotive and a scope for reduction in size of the locomotive. OBJECTS OF THE INVENTION It is therefore an object of the invention to propose a method for feeding hotel load in a train by tap changer controlled locomotive transformers which eliminates the disadvantages of prior art. Another object of the invention is to propose a method for feeding hotel load in a train by tap changer controlled locomotive transformers which is capable of improving the efficiency of the locomotive. A still another object of the invention is to propose a method for feeding hotel load in a train by tap changer controller locomotive transformers which reduces the maintenance cost of the locomotive. A further object of the invention is to propose a method for feeding hotel load in a train by tap changer controlled locomotive transformers which reduces the ambient temperature inside the locomotive. A still further object of the invention is to propose a method for feeding hotel load in a train by tap changer controlled locomotive transformers which results a cleaner environment with more free space inside the locomotive and reduces chance of fire hazard. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS Fig. 1 - Shows the arrangement of Regulating and Main transformers where output "Z" of the regulating transformer is fed to the main transformer. Fig. 2 - Shows the winding of the regulating transformer being divided into 32 parts corresponding to 32 voltage steps. Fig. 3 - Shows the main transformer with primary winding P1 and P2 and secondary winding (S1, S'1) and (S2, S'2) with input "Z" from regulating transformer. Fig. 4 - Shows common magnetic core for regulating and main transformer. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION A locomotive transformer is a single phase transformer that draws power from one phase traction over head line ( 1 wire) with ground return through rails. The transformer is fed power at 25 Kv ( 27 kv at no-load) from the traction over head line. As shown in Fig. 1 the locomotive transformer has two transformers inside; one Regulating transformer (R) and one Main transformer (M). These two transformers are inter-connected in cascade arrangement i.e. the output of the Regulating transformer (R) is fed to the Main transformer (M). The first transformer is a Regulating transformer which is an Auto transformer that draws power from the over head line at terminal A 33. The secondary winding of the Regulating transformer (R) is divided into 32 parts as shown in Fig. 2. The 32 parts of the winding corresponds to 32 voltage steps i.e. the voltage output is different at different taps. There is a Tap changer to which all the 32 taps are connected in a progressively increased manner. At each tap position the output voltage of the Regulating transformer (R) is different. The output of the Regulating transformer (R) (through Tap Changer) goes through terminal "Z" to the Main transformer (M) as shown in Fig. 2. The primary winding of the Regulating transformer is rated for 25 kV at 100% traction load. For example for a traction load of 3900 kVA of a locomotive the Regulating transformer is rated for ( 3900 KVA + Auxiliary load - if any) where the hotel load configuration is not provided. The output of the Regulating transformer (R) is fed on to the Main transformer (M). The main transformer is a fixed ratio transformer and caters to the traction purpose only. It has One primary traction winding (P1, P2) and two secondary windings (S1, S'1) and (S2, S'2). The primary winding is rated for 100% traction (traction load alone) and each secondary winding is rated at 760 volts at 50% of traction load capacity. For example, for a transformer of 3900 kVA traction load capacity will have a Main transformer with primary winding rated for 3900 kVA and each of the two secondary will be rated for a load of 1950 kVA. At different taps, the output of the Regulating transformer is different. This voltage is fed to the main transformer to give different voltage at its secondary winding, which are connected to the traction motors. As shown in Fig. 4, the main transformer and the Regulating transformer have a single magnetic circuit. The magnetic flux generated by the Regulating transformer finds a return path of the magnetic circuit of the Main transformer. From the regulating transformer the voltage fed to the Main transformer are different which results a proportionately variable magnetic flux of the main transformer. With change of tappings (tap positions 1 to 32) the voltage input to Main transformer (increases) and hence the flux density in main transformer also (increases) proportionately. But the magnetic flux OR in the Regulating transformer does not change. This is because the input voltage from the Overhead line is fixed at 25 kv (27 kv at no- load). That means, whatever be the tap position (from 1 to 32), whatever may be the output voltage of the secondary winding (0 to 100% voltage) and whatever may be the speed of the train (even at Zero speed) the flux in the Regulating transformer always remains constant. So this winding, called as "Hotel Load Winding" has been provided on the magnetic path of the Regulating winding to generate an additional voltage source. The output of this winding is converted to D C by means of rectifiers. This D C power is utilized to take care of the Hotel load requirements inside the train. The rating of the Regulating transformer is increased by the hotel load winding capacity. For example, with a 1000 kVA Hotel load in a transformer with 3900 kVA traction capacity, the rating of the Regulating transformer becomes ( 3900 + 1000 + Auxiliary load- if any). Inside the train normally a diesel generator is provided to generate D C power to take care of the Hotel load inside the train. For example, for a journey of 15 hours, to cater for a Hotel load of 500 kVA, around 2000 liter of Diesel is required. By providing an additional winding in the magnetic path of the Regulating transformer of the train mounted locomotive transformer, a separate voltage source is developed. This voltage is independent of the tap position of the train and independent of the speed of the train. This voltage is converted to a D C source and utilized for Hotel load. WE CLAIM: 1. A method for feeding hotel load in a train by tap changer controlled locomotive transformers comprising: drawing of power at for example 25 KV from the traction overhead line by regulating transformer (R); dividing the winding of the regulating transformer (R) into a plurality of parts that corresponds to a plurality of voltage steps; feeding the output of the regulating transformer (R) to main transformer (M); arranging one primary winding (P1, P2) and two secondary winding (S1, S'1 and S2-S'2) in the main transformer (M); connecting the secondary windings of main transformer (M) to traction motors; arranging a single magnetic circuit for both the regulating transformer (R) and main transformer (M); keeping the magnetic flux (OR) in the regulating transformer unchanged that generates additional voltage source; characterized in that this output being converted to D C by means of rectifiers wherein this D C power is utilized for hotel load. 2. A method as claimed in claim 1, wherein the magnetic flux (OR) in the regulating transformer remains constant for any position of tap, for any output voltage and for any speed of the train. 3. A method as claimed in claim 1, wherein the rating of the regulating transformer is increased by the hotel winding capacity. 4. A method as claimed in claim 1, wherein the traction load is catered by the main transformer. The regulating transformer (R) which draws power at 25 KV from the traction overhead line is divided into 32 parts that corresponds to 32 voltage steps. The output of the regulating transformer is fed to main transformer (M) which has an arrangement of one primary winding (P1, P2) and two secondary winding (S1, S'1 and S2, S'2). A single magnetic circuit is arranged for both the transformers (R) and (M). The flux of the Main transformer changes with change of tappings. But the magnetic flux (ΦR) in the regulating transformer (R) remains constant which generates additional voltage source for the Hotel load winding. Owing to the constant flux this voltage constant at all the speed (tap position) of the train. This voltage output is converted to D C by means of rectifiers and this D C power is utilized to meet the hotel load requirements.

Full Text

FIELD OF INVENTION
The invention relates to a method for feeding hotel load in a train by tap changer
controlled locomotive transformers. More particularly the invention relates to a
method for feeding hotel load in a train by tap changer controlled locomotive
transformers. Controlled locomotive transformers that replaces an existing diesel
generator set capsule used for hotel load by an electrical system.
BACKGROUND OF THE INVENTION
In a conventional D.C. locomotive, a diesel generator set capsule is provided to
feed the lighting, fan and catering load which are collectively known as "hotel
load" in a train which is a requirement besides catering to the traction load.
Owing to use of diesel, the environment becomes hazardous and the
maintenance cost is high. There exist also chances of fire hazards. The space
occupied by the whole set up is huge. Cost of running the set is also very high.
For a run of 15 hours, to cater for a "hotel load" of 500KVA around 2000 litre
diesel is consumed. Because of the Generator Set and its accessories, the
temperature inside the locomotive is as high as 55°C.
Accordingly, there exists a need to overcome the disadvantages of prior art. The
present invention replaces the use of diesel by electricity for the purpose of
catering to hotel load. This use of electricity increases the efficiency of the
locomotive and provides a cleaner environment. This also reduces the
maintenance cost of the locomotive and chances of fire hazard inside the
locomotive is reduced due to elimination of the diesel requirement of the Gen-Set
Capsule required for Hotel load. The use of electricity also results in the
reduction of the ambient temperature due to reduction in exhaust gas of the

locomotive. This invention also relates to generating more free space inside the
locomotive and a scope for reduction in size of the locomotive.
OBJECTS OF THE INVENTION
It is therefore an object of the invention to propose a method for feeding hotel
load in a train by tap changer controlled locomotive transformers which
eliminates the disadvantages of prior art.
Another object of the invention is to propose a method for feeding hotel load in a
train by tap changer controlled locomotive transformers which is capable of
improving the efficiency of the locomotive.
A still another object of the invention is to propose a method for feeding hotel
load in a train by tap changer controller locomotive transformers which reduces
the maintenance cost of the locomotive.
A further object of the invention is to propose a method for feeding hotel load in
a train by tap changer controlled locomotive transformers which reduces the
ambient temperature inside the locomotive.
A still further object of the invention is to propose a method for feeding hotel
load in a train by tap changer controlled locomotive transformers which results a
cleaner environment with more free space inside the locomotive and reduces
chance of fire hazard.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig. 1 - Shows the arrangement of Regulating and Main transformers where

output "Z" of the regulating transformer is fed to the main transformer.
Fig. 2 - Shows the winding of the regulating transformer being divided into 32
parts corresponding to 32 voltage steps.
Fig. 3 - Shows the main transformer with primary winding P1 and P2 and
secondary winding (S1, S'1) and (S2, S'2) with input "Z" from regulating
transformer.
Fig. 4 - Shows common magnetic core for regulating and main transformer.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION
A locomotive transformer is a single phase transformer that draws power from
one phase traction over head line ( 1 wire) with ground return through rails. The
transformer is fed power at 25 Kv ( 27 kv at no-load) from the traction over
head line. As shown in Fig. 1 the locomotive transformer has two transformers
inside; one Regulating transformer (R) and one Main transformer (M). These two
transformers are inter-connected in cascade arrangement i.e. the output of the
Regulating transformer (R) is fed to the Main transformer (M).
The first transformer is a Regulating transformer which is an Auto transformer
that draws power from the over head line at terminal A 33. The secondary
winding of the Regulating transformer (R) is divided into 32 parts as shown in
Fig. 2. The 32 parts of the winding corresponds to 32 voltage steps i.e. the
voltage output is different at different taps. There is a Tap changer to which all
the 32 taps are connected in a progressively increased manner. At each tap

position the output voltage of the Regulating transformer (R) is different. The
output of the Regulating transformer (R) (through Tap Changer) goes through
terminal "Z" to the Main transformer (M) as shown in Fig. 2. The primary winding
of the Regulating transformer is rated for 25 kV at 100% traction load. For
example for a traction load of 3900 kVA of a locomotive the Regulating
transformer is rated for ( 3900 KVA + Auxiliary load - if any) where the hotel
load configuration is not provided.
The output of the Regulating transformer (R) is fed on to the Main transformer
(M). The main transformer is a fixed ratio transformer and caters to the traction
purpose only. It has One primary traction winding (P1, P2) and two secondary
windings (S1, S'1) and (S2, S'2). The primary winding is rated for 100% traction
(traction load alone) and each secondary winding is rated at 760 volts at 50% of
traction load capacity.
For example, for a transformer of 3900 kVA traction load capacity will have a
Main transformer with primary winding rated for 3900 kVA and each of the two
secondary will be rated for a load of 1950 kVA.
At different taps, the output of the Regulating transformer is different. This
voltage is fed to the main transformer to give different voltage at its secondary
winding, which are connected to the traction motors.
As shown in Fig. 4, the main transformer and the Regulating transformer have a
single magnetic circuit. The magnetic flux generated by the Regulating
transformer finds a return path of the magnetic circuit of the Main transformer.
From the regulating transformer the voltage fed to the Main transformer are
different which results a proportionately variable magnetic flux of the main
transformer. With change of tappings (tap positions 1 to 32) the voltage input to

Main transformer (increases) and hence the flux density in main transformer also
(increases) proportionately.
But the magnetic flux OR in the Regulating transformer does not change. This is
because the input voltage from the Overhead line is fixed at 25 kv (27 kv at no-
load). That means, whatever be the tap position (from 1 to 32), whatever may
be the output voltage of the secondary winding (0 to 100% voltage) and
whatever may be the speed of the train (even at Zero speed) the flux in the
Regulating transformer always remains constant.
So this winding, called as "Hotel Load Winding" has been provided on the
magnetic path of the Regulating winding to generate an additional voltage
source. The output of this winding is converted to D C by means of rectifiers.
This D C power is utilized to take care of the Hotel load requirements inside the
train. The rating of the Regulating transformer is increased by the hotel load
winding capacity. For example, with a 1000 kVA Hotel load in a transformer with
3900 kVA traction capacity, the rating of the Regulating transformer becomes (
3900 + 1000 + Auxiliary load- if any). Inside the train normally a diesel
generator is provided to generate D C power to take care of the Hotel load inside
the train. For example, for a journey of 15 hours, to cater for a Hotel load of 500
kVA, around 2000 liter of Diesel is required. By providing an additional winding in
the magnetic path of the Regulating transformer of the train mounted locomotive
transformer, a separate voltage source is developed. This voltage is independent
of the tap position of the train and independent of the speed of the train. This
voltage is converted to a D C source and utilized for Hotel load.

WE CLAIM:
1. A method for feeding hotel load in a train by tap changer controlled
locomotive transformers comprising:
drawing of power at for example 25 KV from the traction overhead line by
regulating transformer (R);
dividing the winding of the regulating transformer (R) into a plurality
of parts that corresponds to a plurality of voltage steps;
feeding the output of the regulating transformer (R) to main transformer
(M);
arranging one primary winding (P1, P2) and two secondary winding (S1, S'1
and S2-S'2) in the main transformer (M);
connecting the secondary windings of main transformer (M) to traction
motors;
arranging a single magnetic circuit for both the regulating transformer (R)
and main transformer (M);
keeping the magnetic flux (OR) in the regulating transformer unchanged
that generates additional voltage source; characterized in that this output
being converted to D C by means of rectifiers wherein this D C power is
utilized for hotel load.

2. A method as claimed in claim 1, wherein the magnetic flux (OR) in the
regulating transformer remains constant for any position of tap, for any
output voltage and for any speed of the train.
3. A method as claimed in claim 1, wherein the rating of the regulating
transformer is increased by the hotel winding capacity.
4. A method as claimed in claim 1, wherein the traction load is catered by
the main transformer.

The regulating transformer (R) which draws power at 25 KV from the traction
overhead line is divided into 32 parts that corresponds to 32 voltage steps. The
output of the regulating transformer is fed to main transformer (M) which has
an arrangement of one primary winding (P1, P2) and two secondary winding (S1,
S'1 and S2, S'2). A single magnetic circuit is arranged for both the transformers
(R) and (M). The flux of the Main transformer changes with change of tappings.
But the magnetic flux (ΦR) in the regulating transformer (R) remains constant
which generates additional voltage source for the Hotel load winding. Owing to
the constant flux this voltage constant at all the speed (tap position) of the train.
This voltage output is converted to D C by means of rectifiers and this D C power
is utilized to meet the hotel load requirements.

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Patent Number

271980

Indian Patent Application Number

503/KOL/2009

PG Journal Number

12/2016

Publication Date

18-Mar-2016

Grant Date

11-Mar-2016

Date of Filing

20-Mar-2009

Name of Patentee

BHARAT HEAVY ELECTRICALS LIMITED

Applicant Address

REGIONAL OFFICES AT REGIONAL OPERATIONS DIVISION (ROD), PLOT NO: 9/1, DJBLOCK 3RD FLOOR, KARUNAMOYEE, SALT LAKE CITY, KOLKATA-700091, HAVING ITS REGISTERED OFFICE AT BHEL HOUSE, SIRI FORT, NEW DELHI-110049, INDIA

Inventors:

#	Inventor's Name	Inventor's Address
1	RAJENDRA KUMAR MOHAPATRA	TRANSFORMER DESIGN DEPARTMENT

PCT International Classification Number

H02M1/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA