Indian Patents. 279812:A SYSTEM FOR ON-LINE DIAGNOSING OF DYNAMIC CHARACTERISTIC OF AN ARC WELDING SOURCE

Title of Invention	A SYSTEM FOR ON-LINE DIAGNOSING OF DYNAMIC CHARACTERISTIC OF AN ARC WELDING SOURCE
Abstract	The invention relates to a metal joining process of welding using electric arc as the source of heat for melting the joinable metals. More particularly, the invention relates to a system for diagnosing the dynamic characteristics of arc welding power source.

Full Text	FIELD OF INVENTION The invention relates to a metal joining process of welding using electric arc as the source of heat for melting the joinable metals. More particularly, the invention relates to a system for diagnosing the dynamic characteristics of arc welding power source. BACKGROUND OF THE INVENTION Welding power source is an electrical equipment specifically designed to cater to different types of arc welding applications. Such power supply systems are manufactured worldwide; M/s. Lincoln Electric, Esab, Memco are some of the well-known industries manufacturing such systems. The electric power supplied by the welding power source generates arc between the electrode and the work piece. This arc is a source of heat for melting the materials to be joined. Continuous and stable arc is essential for achieving good quality welding. Welding equipment manufacturers test the power sources for electrical characteristics and safety requirements according to standard of the respective nation. Standards pertaining to welding power sources are : BS-7570, BS-672 etc. Static characteristics of a power source are evaluated by testing under static conditions without the welding arc. Dynamic characteristics tests are carried out during welding operation. Dynamic characteristics of the power source are generally not carried out by the manufacturers. The static characteristics of the welding power source are evaluated by using standard electrical measuring instruments, by adapting the procedure defined by the testing methods. Understanding dynamic characteristics of the welding power source is required to evaluate the behavior of the welding power source during welding. This dynamic characteristic requires special purpose evaluation system and cannot be evaluated using standard electrical measuring and testing instruments. Assesing the dynamic behaviour of a power source is very important to ensure the quality of the welding produced. Unfortunately, this dynamic behaviour or dynamic characteristics of a welding power source is not evaluated by the manufacturers because there is no standard instrument available to evaluate these dynamic characteristics. OBJECTS OF THE INVENTION It is an object of the invention to provide a system for diagnising the dynamic characteristics of arc welding power source to produce better welding qualities. Another object of the invention is to provide a system for diagnising the dynamic characteristics of arc welding power source, which determines the stability, ignition characteristics and the spatter characteristic of the arc for evaluating the dynamic characteristics of the power source. A further object of the invention is to provide a system for diagnising the dynamic characteristics of arc welding power source in which welding voltage and current of a power source is captured in real time for subsequent processing and evaluation based on the recorded data thereby evaluating the dynamic characteristics of the power source. SUMMARY OF THE INVENTION An exclusive power source diagnostic system characterizes the welding power source for its welding qualities. The system employs a computerized diagnostic interface using microprocessor hardware and software for data acquisition and evaluation of dynamic characteristics of the welding power sources, such as the stability, ignition characteristics and the spatter characteristics of the arc. Thus the performance of the welding power source can be uniquely evaluated by this diagnostic system. The diagnostic system essentially collects the voltage and current signals during welding and analyses the dynamic characteristics using a computer program, thus evaluating the quality level of the arc welding power source in relation to one another. The diagnostic system is adapted to carry-out evaluation of the dynamic characteristics of the welding power source. The evaluation comprises determining the dynamic behaviour of the power source during real-time welding operation. A data acquisition module captures welding voltage and current in real time and the recorded data is processed by a computer through a software and the following index values are calculated and displayed along with the waveform recording. a. Arc stability index b. Arc ignition index c. Spatter index The arc stability index value indicates the stability of the arc produced by the power source under evaluation while keeping the quality of the welding consumable, welding parameter and the welder constant. The arc ignition index indicates the re-ignition characteristic of the arc during short / open circuits. The spatter index is an indication of spatter level produced by the arc during welding. In addition, the routine tests are to be conducted as per relevant standards. Accordingly, the present invention provides a system for on-line diagnosing the dynamic characteristics of an arc welding power source, comprising atleast one voltage sensor for sensing the welding voltage, atleast one current sensor for sensing the arc current signal, an analog signal conditioner receiving the voltage and current data in the form of analog signals from the atleast one voltage sensor and the atleast one current sensor and converting the analog signals to digital signals, a micro controller based data acquisition module receiving the digital signals from the analog signal conditioner for processing and storing the processed data; and an apparatus receiving the processed data from the data acquisition module and having a computer program operable to interpret the dynamic characteristics of the power source. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS Fig. 1 - a block diagram illustrating the generic concept of the present invention Fig. 2 - a block diagram illustrating a system for diagnising the dynamic characteristics of arc welding power source according to a preferred embodiment of the present invention Fig. 3 - showing a graphical illustration of the welding voltage and current wave forms including the index values according to the invention. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION As shown in Fig - 1 Welding power source (1) supplies current and voltage for the weld zone. A work piece (5) is connected to a return terminal of the power source (1) through a return cable (3A). An welding electrode (6) is connected to the source terminal of the power source (1) through a cable first (3). A welding arc (7) is generated between the electrode (6) and the work piece (5). A Voltage sensor (2) senses the welding voltage and sends a signal to a signal conditioner module (10) through a second cable (8). A current sensor (4) senses the welding current and sends a signal to the signal conditioner module (10) through a third cable (9). The conditioned signal is fed to a micro-controller based hardware (12) through a fourth cable (11). A personal computer (14) evaluates the power source under diagnosis. A serial communication interface (13) links the personal computer (14) to the micro controller hardware (12). The welding power source (1) is connected to the electrode (6) and the welding arc (7) is ignited between the electrode (6) and the work piece (5). Generally, the voltage and current data are monitored using, analog / digital meters. To evaluate the dynamic characteristics of the power source (1), the current and voltage data are to be continuously recorded and stored in the personal computer memory for evaluation. The details of the diagnostic system, for evaluating dynamic characteristics of the arc welding power source are shown in fig. 2. This system consists of two sensors - one is a current sensor (4) and the other is a voltage sensor (2). The current and voltage output from the welding power source under test are given to these sensors as input. The signal outputs from the sensors (2,4) are processed by a signal conditioner module (10) and then sent to an analog to digital converter (ADC). Power supply unit (1) supplies DC power to the signal conditioner (10) and the analog to digital converter (ADC). Mains power supply 230V AC (21) is converted to generate DC power required for operation of the module (10). The digital information from the ADC is read by the micro controller CPU (12) of the micro controller module (9) and the digital data is stored in a memory (15) of the hardware (9). A timer function (16) of the micro controller (9) is used for programming the sampling rate of the data collected from the ADC. A keypad (17) and a display (18) are used for inputting data and viewing the status during hardware debugging. The data is collected over a period of time set by the software option and is stored in the volatile memory (15) of the micro controller (9). The stored data is then transferred to the host PC (14) through RS 232 serial port (13) for processing and calculation of the index values. Serial communication cable (19) interlinks the diagnostic hardware (12) and personal computer (14). A diagnostic software (20) being a menu driven program runs on the PC (14) and controls the flow of the operation. The data acquisition and processing software (20) has been developed using Visual Basic platform. The pattern of the weld current and voltages are plotted as shown in the fig. 3 and the index levels are indicated on the PC screen. According to the embodiment of the invention illustrated in fig - 2, the voltage sensor (2), and the current sensor (4) are non contact type sensors commercially available in the market. The personal computer (14) is a standard PC operating on MS Windows platform. Module (9) is a commercially available 8051 based micro controller board, programmed for this application. Module (7) is a board consisting of analog signal conditioner. ADC and power supply and was made to requirement. WE CLAIM 1. A system for on-line diagnosing the dynamic characteristics of an arc welding power source (1), comprising; - atleast one voltage sensor (1) for sensing the welding voltage; - atleast one current sensor (2) for sensing the arc current signal; - an analog signal conditioner (10) receiving the voltage and current data in the form of analog signals from the atleast one voltage sensor (1) and the atleast one current sensor (2), and converting the analog signals to digital signals; - a micro controller based data acquisition module (14) receiving the digital signals from the analog signal conditioner (10) for processing and storing the processed data; and - an apparatus (14) receiving the processed data from the data acquisition module (14) and having a 'computer program (20) operable to interpret the dynamic characteristics of the power source (1). 2. The system as claimed in claim 1, wherein a serial communication interface (13) connects the apparatus (14) to the micro controller (12). 3. The system as claimed in claim 1, wherein micro-controller (12) having a memory (15) for storing the processed data. 4. A system for on-line diagnosing the dynamic characteristics of an arc welding power source, as substantially described herein with reference to the accompanying drawings. The invention relates to a metal joining process of welding using electric arc as the source of heat for melting the joinable metals. More particularly, the invention relates to a system for diagnosing the dynamic characteristics of arc welding power source.

Full Text

FIELD OF INVENTION
The invention relates to a metal joining process of welding using electric arc as
the source of heat for melting the joinable metals. More particularly, the
invention relates to a system for diagnosing the dynamic characteristics of arc
welding power source.
BACKGROUND OF THE INVENTION
Welding power source is an electrical equipment specifically designed to cater to
different types of arc welding applications. Such power supply systems are
manufactured worldwide; M/s. Lincoln Electric, Esab, Memco are some of the
well-known industries manufacturing such systems.
The electric power supplied by the welding power source generates arc between
the electrode and the work piece. This arc is a source of heat for melting the
materials to be joined. Continuous and stable arc is essential for achieving good
quality welding. Welding equipment manufacturers test the power sources for
electrical characteristics and safety requirements according to standard of the
respective nation. Standards pertaining to welding power sources are : BS-7570,
BS-672 etc. Static characteristics of a power source are evaluated by testing
under static conditions without the welding arc. Dynamic characteristics tests are
carried out during welding operation. Dynamic characteristics of the power
source are generally not carried out by the manufacturers.
The static characteristics of the welding power source are evaluated by using
standard electrical measuring instruments, by adapting the procedure defined by
the testing methods. Understanding dynamic characteristics of the welding
power source is required to evaluate the behavior of the welding power source
during welding. This dynamic characteristic requires special purpose evaluation
system and cannot be evaluated using standard electrical measuring and testing
instruments.
Assesing the dynamic behaviour of a power source is very important to ensure
the quality of the welding produced. Unfortunately, this dynamic behaviour or
dynamic characteristics of a welding power source is not evaluated by the
manufacturers because there is no standard instrument available to evaluate
these dynamic characteristics.
OBJECTS OF THE INVENTION
It is an object of the invention to provide a system for diagnising the dynamic
characteristics of arc welding power source to produce better welding qualities.
Another object of the invention is to provide a system for diagnising the dynamic
characteristics of arc welding power source, which determines the stability,
ignition characteristics and the spatter characteristic of the arc for evaluating the
dynamic characteristics of the power source.
A further object of the invention is to provide a system for diagnising the
dynamic characteristics of arc welding power source in which welding voltage
and current of a power source is captured in real time for subsequent processing
and evaluation based on the recorded data thereby evaluating the dynamic
characteristics of the power source.
SUMMARY OF THE INVENTION
An exclusive power source diagnostic system characterizes the welding power
source for its welding qualities. The system employs a computerized diagnostic
interface using microprocessor hardware and software for data acquisition and
evaluation of dynamic characteristics of the welding power sources, such as the
stability, ignition characteristics and the spatter characteristics of the arc. Thus
the performance of the welding power source can be uniquely evaluated by this
diagnostic system. The diagnostic system essentially collects the voltage and
current signals during welding and analyses the dynamic characteristics using a
computer program, thus evaluating the quality level of the arc welding power
source in relation to one another.
The diagnostic system is adapted to carry-out evaluation of the dynamic
characteristics of the welding power source. The evaluation comprises
determining the dynamic behaviour of the power source during real-time welding
operation. A data acquisition module captures welding voltage and current in real
time and the recorded data is processed by a computer through a software and
the following index values are calculated and displayed along with the waveform
recording.
a. Arc stability index
b. Arc ignition index
c. Spatter index
The arc stability index value indicates the stability of the arc produced by the
power source under evaluation while keeping the quality of the welding
consumable, welding parameter and the welder constant. The arc ignition index
indicates the re-ignition characteristic of the arc during short / open circuits. The
spatter index is an indication of spatter level produced by the arc during welding.
In addition, the routine tests are to be conducted as per relevant standards.
Accordingly, the present invention provides a system for on-line diagnosing the
dynamic characteristics of an arc welding power source, comprising atleast one
voltage sensor for sensing the welding voltage, atleast one current sensor for
sensing the arc current signal, an analog signal conditioner receiving the voltage
and current data in the form of analog signals from the atleast one voltage
sensor and the atleast one current sensor and converting the analog signals to
digital signals, a micro controller based data acquisition module receiving the
digital signals from the analog signal conditioner for processing and storing the
processed data; and an apparatus receiving the processed data from the data
acquisition module and having a computer program operable to interpret the
dynamic characteristics of the power source.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig. 1 - a block diagram illustrating the generic concept of the present invention
Fig. 2 - a block diagram illustrating a system for diagnising the dynamic
characteristics of arc welding power source according to a preferred embodiment
of the present invention
Fig. 3 - showing a graphical illustration of the welding voltage and current wave
forms including the index values according to the invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION
As shown in Fig - 1 Welding power source (1) supplies current and voltage for
the weld zone. A work piece (5) is connected to a return terminal of the power
source (1) through a return cable (3A). An welding electrode (6) is connected to
the source terminal of the power source (1) through a cable first (3). A welding
arc (7) is generated between the electrode (6) and the work piece (5). A Voltage
sensor (2) senses the welding voltage and sends a signal to a signal conditioner
module (10) through a second cable (8). A current sensor (4) senses the welding
current and sends a signal to the signal conditioner module (10) through a third
cable (9). The conditioned signal is fed to a micro-controller based hardware (12)
through a fourth cable (11). A personal computer (14) evaluates the power
source under diagnosis. A serial communication interface (13) links the personal
computer (14) to the micro controller hardware (12).
The welding power source (1) is connected to the electrode (6) and the welding
arc (7) is ignited between the electrode (6) and the work piece (5). Generally,
the voltage and current data are monitored using, analog / digital meters. To
evaluate the dynamic characteristics of the power source (1), the current and
voltage data are to be continuously recorded and stored in the personal
computer memory for evaluation.
The details of the diagnostic system, for evaluating dynamic characteristics of
the arc welding power source are shown in fig. 2. This system consists of two
sensors - one is a current sensor (4) and the other is a voltage sensor (2). The
current and voltage output from the welding power source under test are given
to these sensors as input. The signal outputs from the sensors (2,4) are
processed by a signal conditioner module (10) and then sent to an analog to
digital converter (ADC). Power supply unit (1) supplies DC power to the signal
conditioner (10) and the analog to digital converter (ADC). Mains power supply
230V AC (21) is converted to generate DC power required for operation of the
module (10). The digital information from the ADC is read by the micro controller
CPU (12) of the micro controller module (9) and the digital data is stored in a
memory (15) of the hardware (9). A timer function (16) of the micro controller
(9) is used for programming the sampling rate of the data collected from the
ADC. A keypad (17) and a display (18) are used for inputting data and viewing
the status during hardware debugging. The data is collected over a period of
time set by the software option and is stored in the volatile memory (15) of the
micro controller (9). The stored data is then transferred to the host PC (14)
through RS 232 serial port (13) for processing and calculation of the index
values. Serial communication cable (19) interlinks the diagnostic hardware (12)
and personal computer (14). A diagnostic software (20) being a menu driven
program runs on the PC (14) and controls the flow of the operation. The data
acquisition and processing software (20) has been developed using Visual Basic
platform. The pattern of the weld current and voltages are plotted as shown in
the fig. 3 and the index levels are indicated on the PC screen.
According to the embodiment of the invention illustrated in fig - 2, the voltage
sensor (2), and the current sensor (4) are non contact type sensors commercially
available in the market. The personal computer (14) is a standard PC operating
on MS Windows platform. Module (9) is a commercially available 8051 based
micro controller board, programmed for this application. Module (7) is a board
consisting of analog signal conditioner. ADC and power supply and was made to
requirement.
WE CLAIM
1. A system for on-line diagnosing the dynamic characteristics of an arc
welding power source (1), comprising;
- atleast one voltage sensor (1) for sensing the welding voltage;
- atleast one current sensor (2) for sensing the arc current signal;
- an analog signal conditioner (10) receiving the voltage and current
data in the form of analog signals from the atleast one voltage
sensor (1) and the atleast one current sensor (2), and converting
the analog signals to digital signals;
- a micro controller based data acquisition module (14) receiving the
digital signals from the analog signal conditioner (10) for
processing and storing the processed data; and
- an apparatus (14) receiving the processed data from the data
acquisition module (14) and having a 'computer program (20)
operable to interpret the dynamic characteristics of the power
source (1).
2. The system as claimed in claim 1, wherein a serial communication
interface (13) connects the apparatus (14) to the micro controller (12).
3. The system as claimed in claim 1, wherein micro-controller (12) having a
memory (15) for storing the processed data.
4. A system for on-line diagnosing the dynamic characteristics of an arc
welding power source, as substantially described herein with reference to
the accompanying drawings.

The invention relates to a metal joining process of welding using electric arc as the
source of heat for melting the joinable metals. More particularly, the invention relates to a
system for diagnosing the dynamic characteristics of arc welding power source.

Documents:

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Patent Number

279812

Indian Patent Application Number

363/KOL/2005

PG Journal Number

05/2017

Publication Date

03-Feb-2017

Grant Date

31-Jan-2017

Date of Filing

28-Apr-2005

Name of Patentee

BHARAT HEAVY ELECTRICALS LIMITED

Applicant Address

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	VELANI RATCHANNIYA SAMUEL	BHARAT HEAVY ELECTRICALS LIMITED, TIRUCHIRAPPALLI 620 014
2	SIVASANKARAN MANOHARAN	BHARAT HEAVY ELECTRICALS LIMITED, TIRUCHIRAPPALI 620 014
3	VICTOR PAUL DANIEL	BHARAT HEAVY ELECTRICALS LIMITED, TIRUCHIRAPPALI 620 014

PCT International Classification Number

B23K 9/10

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA