Apuntes Sobre Maquinas de Soldar

7/28/2019 Apuntes Sobre Maquinas de Soldar

1/32

1.42 WELDING TRANSFORMERS

Figure 1.59shows a schematic diagram of a welding transformer having thin primary windings with a large number of turns.On the other hand, the secondary has more area of cross-section and less number of turns ensuring less voltage and very

high current in the secondary. One end of the secondary is connected to the welding electrode, whereas the other end is

connected to the pieces to be welded. If any high current flows, heat is produced due to the contact resistance between the

electrode and the pieces to be welded. The generated heat melts a tip of the electrode and the gap between the two pieces

is filled.

Figure 1.59 Welding Transformer

Figure 1.60 Volt-ampere Characteristic of a Welding Transformer

The winding used for the welding transformer is highly reactive. Otherwise, a separate reactor may be added in series with

the secondary winding.Figure 1.60shows the volt-ampere characteristic of a welding transformer.

1.42.1 Reactors Used with Welding Transformers

To control the arc, various reactors are used with welding transformers. Some methods to control the arc are given below:

i. Tapped reactor: With the help of taps on the reactor, the output current is regulated. This has limite number ofcurrent settings shown inFigure 1.61.

ii. Moving coil reactor:Figure 1.62shows a moving coil reactor in which the reactive distance between primary andsecondary is adjusted. The current becomes less if the distance between the coils is large.

Figure 1.61 Tapped Reactor
http://my.safaribooksonline.com/9788131760901/navPoint-85#ch001-f059http://my.safaribooksonline.com/9788131760901/navPoint-85#ch001-f059http://my.safaribooksonline.com/9788131760901/navPoint-85#ch001-f060http://my.safaribooksonline.com/9788131760901/navPoint-85#ch001-f060http://my.safaribooksonline.com/9788131760901/navPoint-85#ch001-f061http://my.safaribooksonline.com/9788131760901/navPoint-85#ch001-f061http://my.safaribooksonline.com/9788131760901/navPoint-85#ch001-f061http://my.safaribooksonline.com/9788131760901/navPoint-85#ch001-f062http://my.safaribooksonline.com/9788131760901/navPoint-85#ch001-f062http://my.safaribooksonline.com/9788131760901/navPoint-85#ch001-f062http://my.safaribooksonline.com/9788131760901/navPoint-85#ch001-f062http://my.safaribooksonline.com/9788131760901/navPoint-85#ch001-f061http://my.safaribooksonline.com/9788131760901/navPoint-85#ch001-f060http://my.safaribooksonline.com/9788131760901/navPoint-85#ch001-f059


2/32

Figure 1.62 Moving Coil Reactor

iii. Moving shunt reactor: Figure 1.63 shows a moving shunt reactor in which the position of the central magneticshunt can be adjusted. Change of the output current is obtained due to the adjustment of the shunted flux.

iv. Continuously variable reactor:Figure 1.64shows a continuously variable reactor in which the height of the reactoris continuously varied. Greater reactance is obtained due to greater core insertion and hence the output current

is less.

v. Saturable reactor:Figure 1.65shows a saturable reactor. To adjust the reactance of the reactor, the required DCexcitation is obtained from a DC controlled transducer. Reactor approaches saturation if the DC excitationcurrent is more. Therefore, changes of current are obtained due to the change of reactance.

Figure 1.63 Moving Shunt Reactor

Figure 1.64 Continuously Variable Reactor
http://my.safaribooksonline.com/9788131760901/navPoint-85#ch001-f063http://my.safaribooksonline.com/9788131760901/navPoint-85#ch001-f063http://my.safaribooksonline.com/9788131760901/navPoint-85#ch001-f063http://my.safaribooksonline.com/9788131760901/navPoint-85#ch001-f064http://my.safaribooksonline.com/9788131760901/navPoint-85#ch001-f064http://my.safaribooksonline.com/9788131760901/navPoint-85#ch001-f064http://my.safaribooksonline.com/9788131760901/navPoint-85#ch001-f065http://my.safaribooksonline.com/9788131760901/navPoint-85#ch001-f065http://my.safaribooksonline.com/9788131760901/navPoint-85#ch001-f065http://my.safaribooksonline.com/9788131760901/navPoint-85#ch001-f065http://my.safaribooksonline.com/9788131760901/navPoint-85#ch001-f064http://my.safaribooksonline.com/9788131760901/navPoint-85#ch001-f063


3/32

Figure 1.65 Saturable Reactor


4/32

Designing Your Own Transformer

written by: Swagatam edited by: Lamar Stonecypher updated: 11/1/2011

Designing a transformer is not easy simply because the criteria involved with these

devices are critical and elaborate. However some meticulously arranged data regarding

the various calculations can make the procedure easier. Learn how to make a transformer

through using simple formulas.

Introduction

We have already studied a lot about transformers in Bright Hub and we know that its

simply a device used for either stepping-up or stepping down an applied input AC throughmagnetic induction in between its two windings.

Basically a transformer will have the following main components:

Iron core stampings (configured either as U/T or E/I, generally the later is used more

extensively)

Central plastic or ceramic bobbin surrounded by the above iron core stampings

Two windings (electrically isolated and magnetically coupled) using super enameled

copper wire made over the bobbin

Normally the winding which is designated to receive the input supply is termed as thePrimary and the winding which in response to this input produces the required induced

voltage as the output is termed as the secondary winding.

Designing your own transformer as per a specific application can be interesting, but not

feasible without calculating the various parameters typically involved with them. The

following discussion will take you through a few important steps and formulas and explain

how to make a transformer.

amorphous c core

www.magneticmaterial.cn

China professional manufacturer amorphous c core,high quality

Voltage Transformer
http://googleads.g.doubleclick.net/aclk?sa=L&ai=CyubWGRJeUdaeJ_PCwQHOwoDwBbmOyIEFkYydnjfAjbcBEAEg6Y2pBigDUPW8vIMDYOXb9ISMFsgBAakCEMgwho2khT6oAwGqBLMBT9AKkonkKqxkYkINhIX_G5gtAusrQ8EvRgHenZw-90k7j-D8Ynv31kdxWf8H4k1Rj4R5F8TJiqtVP8Hi8EcvSMsDj-e_xIQZ1ictllz8Iqk395I5TULQBIRlSon38XsVmFLTDXmhIfO_w1m095zvU4CY4COlX9NfTXNcibWD0l6Gu28PRUKZ7IoTSXatVu8E9hLHb1RBx28RG_ckBrUbSQ4Q5qEoI9aYpONCK-wYsr0f2CWAB7m51jM&num=1&sig=AOD64_0NnQTFUO8PQnf3klrwlp9LfpieyA&client=ca-pub-6409535612800042&adurl=http://www.magneticmaterial.cn/products_detail/%26productId%3Dbd8a0b5e-b51e-4abd-8e7a-f2eaf476ae6b%26comp_stats%3Dcomp-FrontProducts_list01-1301035471982.htmlhttp://googleads.g.doubleclick.net/aclk?sa=L&ai=CyubWGRJeUdaeJ_PCwQHOwoDwBbmOyIEFkYydnjfAjbcBEAEg6Y2pBigDUPW8vIMDYOXb9ISMFsgBAakCEMgwho2khT6oAwGqBLMBT9AKkonkKqxkYkINhIX_G5gtAusrQ8EvRgHenZw-90k7j-D8Ynv31kdxWf8H4k1Rj4R5F8TJiqtVP8Hi8EcvSMsDj-e_xIQZ1ictllz8Iqk395I5TULQBIRlSon38XsVmFLTDXmhIfO_w1m095zvU4CY4COlX9NfTXNcibWD0l6Gu28PRUKZ7IoTSXatVu8E9hLHb1RBx28RG_ckBrUbSQ4Q5qEoI9aYpONCK-wYsr0f2CWAB7m51jM&num=1&sig=AOD64_0NnQTFUO8PQnf3klrwlp9LfpieyA&client=ca-pub-6409535612800042&adurl=http://www.magneticmaterial.cn/products_detail/%26productId%3Dbd8a0b5e-b51e-4abd-8e7a-f2eaf476ae6b%26comp_stats%3Dcomp-FrontProducts_list01-1301035471982.htmlhttp://googleads.g.doubleclick.net/aclk?sa=L&ai=CyubWGRJeUdaeJ_PCwQHOwoDwBbmOyIEFkYydnjfAjbcBEAEg6Y2pBigDUPW8vIMDYOXb9ISMFsgBAakCEMgwho2khT6oAwGqBLMBT9AKkonkKqxkYkINhIX_G5gtAusrQ8EvRgHenZw-90k7j-D8Ynv31kdxWf8H4k1Rj4R5F8TJiqtVP8Hi8EcvSMsDj-e_xIQZ1ictllz8Iqk395I5TULQBIRlSon38XsVmFLTDXmhIfO_w1m095zvU4CY4COlX9NfTXNcibWD0l6Gu28PRUKZ7IoTSXatVu8E9hLHb1RBx28RG_ckBrUbSQ4Q5qEoI9aYpONCK-wYsr0f2CWAB7m51jM&num=1&sig=AOD64_0NnQTFUO8PQnf3klrwlp9LfpieyA&client=ca-pub-6409535612800042&adurl=http://www.magneticmaterial.cn/products_detail/%26productId%3Dbd8a0b5e-b51e-4abd-8e7a-f2eaf476ae6b%26comp_stats%3Dcomp-FrontProducts_list01-1301035471982.htmlhttp://googleads.g.doubleclick.net/aclk?sa=L&ai=Cbt6wGRJeUdaeJ_PCwQHOwoDwBdaV_p0D9r_SxD_AjbcBEAIg6Y2pBigDUJWK_IAHYOXb9ISMFsgBAagDAaoEsgFP0EqPHv0wlVzQ8RDvhf9C1D0Z5SRf3TJRBtWUkjn8SSyU5_UrNvvU8Ko59hviSRuahCEXxJDGu04xzv7sWjhPwAqB4LTEkwLRLmTbUP5g4jrnxnFES9YTgnhLjv3hJVyZQcwHf7d95bDCVr_p1e5FmpbpJKJWmQtbaVvW95vLHd-9fABYV5DxlRteK0qce0i9zRCEsaIqhPv3B9IHtxuNP-bloWhzM26nY8IrDP5g_2UAgAfk294K&num=2&sig=AOD64_1to9umlB-WeEKrPEduuzLc5gw0Xg&client=ca-pub-6409535612800042&adurl=http://www.alibaba.com/premium/voltage_transformer.html%3Fsrc%3Dgoogle%26albch%3Dgoogle%26albcp%3Dcontent_content-old%26albkw%3Dvoltage%2520transformer_Others-Top-Content-Product10-P4P_none_none%26albag%3Dpl_none_voltage%2520transformer_product%26albmt%3Dbroad%26albst%3Dcontent-text%26albom%3DOthers-Top_none_20120827_P4P%26creative%3D16984096494%26placement%3Dwww.brighthubengineering.com%26ptsid%3D1012000032308576%26crea%3D16984096494%26plac%3Dwww.brighthubengineering.com%26netw%3Ddhttp://googleads.g.doubleclick.net/aclk?sa=L&ai=Cbt6wGRJeUdaeJ_PCwQHOwoDwBdaV_p0D9r_SxD_AjbcBEAIg6Y2pBigDUJWK_IAHYOXb9ISMFsgBAagDAaoEsgFP0EqPHv0wlVzQ8RDvhf9C1D0Z5SRf3TJRBtWUkjn8SSyU5_UrNvvU8Ko59hviSRuahCEXxJDGu04xzv7sWjhPwAqB4LTEkwLRLmTbUP5g4jrnxnFES9YTgnhLjv3hJVyZQcwHf7d95bDCVr_p1e5FmpbpJKJWmQtbaVvW95vLHd-9fABYV5DxlRteK0qce0i9zRCEsaIqhPv3B9IHtxuNP-bloWhzM26nY8IrDP5g_2UAgAfk294K&num=2&sig=AOD64_1to9umlB-WeEKrPEduuzLc5gw0Xg&client=ca-pub-6409535612800042&adurl=http://www.alibaba.com/premium/voltage_transformer.html%3Fsrc%3Dgoogle%26albch%3Dgoogle%26albcp%3Dcontent_content-old%26albkw%3Dvoltage%2520transformer_Others-Top-Content-Product10-P4P_none_none%26albag%3Dpl_none_voltage%2520transformer_product%26albmt%3Dbroad%26albst%3Dcontent-text%26albom%3DOthers-Top_none_20120827_P4P%26creative%3D16984096494%26placement%3Dwww.brighthubengineering.com%26ptsid%3D1012000032308576%26crea%3D16984096494%26plac%3Dwww.brighthubengineering.com%26netw%3Ddhttp://googleads.g.doubleclick.net/aclk?sa=L&ai=Cbt6wGRJeUdaeJ_PCwQHOwoDwBdaV_p0D9r_SxD_AjbcBEAIg6Y2pBigDUJWK_IAHYOXb9ISMFsgBAagDAaoEsgFP0EqPHv0wlVzQ8RDvhf9C1D0Z5SRf3TJRBtWUkjn8SSyU5_UrNvvU8Ko59hviSRuahCEXxJDGu04xzv7sWjhPwAqB4LTEkwLRLmTbUP5g4jrnxnFES9YTgnhLjv3hJVyZQcwHf7d95bDCVr_p1e5FmpbpJKJWmQtbaVvW95vLHd-9fABYV5DxlRteK0qce0i9zRCEsaIqhPv3B9IHtxuNP-bloWhzM26nY8IrDP5g_2UAgAfk294K&num=2&sig=AOD64_1to9umlB-WeEKrPEduuzLc5gw0Xg&client=ca-pub-6409535612800042&adurl=http://www.alibaba.com/premium/voltage_transformer.html%3Fsrc%3Dgoogle%26albch%3Dgoogle%26albcp%3Dcontent_content-old%26albkw%3Dvoltage%2520transformer_Others-Top-Content-Product10-P4P_none_none%26albag%3Dpl_none_voltage%2520transformer_product%26albmt%3Dbroad%26albst%3Dcontent-text%26albom%3DOthers-Top_none_20120827_P4P%26creative%3D16984096494%26placement%3Dwww.brighthubengineering.com%26ptsid%3D1012000032308576%26crea%3D16984096494%26plac%3Dwww.brighthubengineering.com%26netw%3Ddhttp://googleads.g.doubleclick.net/aclk?sa=L&ai=CyubWGRJeUdaeJ_PCwQHOwoDwBbmOyIEFkYydnjfAjbcBEAEg6Y2pBigDUPW8vIMDYOXb9ISMFsgBAakCEMgwho2khT6oAwGqBLMBT9AKkonkKqxkYkINhIX_G5gtAusrQ8EvRgHenZw-90k7j-D8Ynv31kdxWf8H4k1Rj4R5F8TJiqtVP8Hi8EcvSMsDj-e_xIQZ1ictllz8Iqk395I5TULQBIRlSon38XsVmFLTDXmhIfO_w1m095zvU4CY4COlX9NfTXNcibWD0l6Gu28PRUKZ7IoTSXatVu8E9hLHb1RBx28RG_ckBrUbSQ4Q5qEoI9aYpONCK-wYsr0f2CWAB7m51jM&num=1&sig=AOD64_0NnQTFUO8PQnf3klrwlp9LfpieyA&client=ca-pub-6409535612800042&adurl=http://www.magneticmaterial.cn/products_detail/%26productId%3Dbd8a0b5e-b51e-4abd-8e7a-f2eaf476ae6b%26comp_stats%3Dcomp-FrontProducts_list01-1301035471982.htmlhttp://googleads.g.doubleclick.net/aclk?sa=L&ai=CyubWGRJeUdaeJ_PCwQHOwoDwBbmOyIEFkYydnjfAjbcBEAEg6Y2pBigDUPW8vIMDYOXb9ISMFsgBAakCEMgwho2khT6oAwGqBLMBT9AKkonkKqxkYkINhIX_G5gtAusrQ8EvRgHenZw-90k7j-D8Ynv31kdxWf8H4k1Rj4R5F8TJiqtVP8Hi8EcvSMsDj-e_xIQZ1ictllz8Iqk395I5TULQBIRlSon38XsVmFLTDXmhIfO_w1m095zvU4CY4COlX9NfTXNcibWD0l6Gu28PRUKZ7IoTSXatVu8E9hLHb1RBx28RG_ckBrUbSQ4Q5qEoI9aYpONCK-wYsr0f2CWAB7m51jM&num=1&sig=AOD64_0NnQTFUO8PQnf3klrwlp9LfpieyA&client=ca-pub-6409535612800042&adurl=http://www.magneticmaterial.cn/products_detail/%26productId%3Dbd8a0b5e-b51e-4abd-8e7a-f2eaf476ae6b%26comp_stats%3Dcomp-FrontProducts_list01-1301035471982.html


5/32

www.alibaba.com

Choose From 1M+ Verified Suppliers. Contact Directly & Get Live Quotes!

Depresin: nuevo ensayo

www.clinlife.mx/Depresin

Padece de depresin? Regstrese para un ensayo aqu.

Ads by Google

Calculating the Core Area (CA) of the Transformer

The Core Area is calculated through the formula given below:

CA = 1.152 (Output Voltage Output Current)

Calculating Turns per Volt (TPV)

It is done with the following formula:

TPV = 1 / (4.44 10-4 CA Flux Density AC frequency)

where the frequency will depend on the particular countrys specifications (either 60 or 50Hz), the standard value for the flux density of normal steel stampings may be taken as 1

Weber/sq.m, for ordinary steel material the value is 1.3 Weber/sq.m

Primary Winding Calculations

Basically three important parameters needs to be figured out while calculating the primary

winding of a transformer, they are as follows:

Current through the primary winding

Number of turns of the primary winding

Area of the primary winding

Lets trace out each of the above expressions:
http://googleads.g.doubleclick.net/aclk?sa=L&ai=Cbt6wGRJeUdaeJ_PCwQHOwoDwBdaV_p0D9r_SxD_AjbcBEAIg6Y2pBigDUJWK_IAHYOXb9ISMFsgBAagDAaoEsgFP0EqPHv0wlVzQ8RDvhf9C1D0Z5SRf3TJRBtWUkjn8SSyU5_UrNvvU8Ko59hviSRuahCEXxJDGu04xzv7sWjhPwAqB4LTEkwLRLmTbUP5g4jrnxnFES9YTgnhLjv3hJVyZQcwHf7d95bDCVr_p1e5FmpbpJKJWmQtbaVvW95vLHd-9fABYV5DxlRteK0qce0i9zRCEsaIqhPv3B9IHtxuNP-bloWhzM26nY8IrDP5g_2UAgAfk294K&num=2&sig=AOD64_1to9umlB-WeEKrPEduuzLc5gw0Xg&client=ca-pub-6409535612800042&adurl=http://www.alibaba.com/premium/voltage_transformer.html%3Fsrc%3Dgoogle%26albch%3Dgoogle%26albcp%3Dcontent_content-old%26albkw%3Dvoltage%2520transformer_Others-Top-Content-Product10-P4P_none_none%26albag%3Dpl_none_voltage%2520transformer_product%26albmt%3Dbroad%26albst%3Dcontent-text%26albom%3DOthers-Top_none_20120827_P4P%26creative%3D16984096494%26placement%3Dwww.brighthubengineering.com%26ptsid%3D1012000032308576%26crea%3D16984096494%26plac%3Dwww.brighthubengineering.com%26netw%3Ddhttp://www.googleadservices.com/pagead/aclk?sa=L&ai=C5Q3gGRJeUdaeJ_PCwQHOwoDwBdi8w7kD8Jyf6EvAjbcBEAMg6Y2pBigDUIaTi8_7_____wFg5dv0hIwWoAHQ-e7YA8gBAakCDN5eMWa0tT6oAwGqBLgBT9A6gzf9MZVc0PEQ74X_QtQ9GeUkX90yUQbVlJI5_EkslOf1Kzb71PCqOfYb4kkbmoQhF8SQxrtOMc7-7Fo4T8AKgeC0xJMC0S5k21D-YOI658ZxREvWE4J4S4794SVcmUHMB3-3feWwwla_6dXuRZqW6SSiVpkLW2lb1vebyx3fvXwAWFeQ8ZUbXit6n-wFTukwhZ9HbqP68RTU7bTyTD_m56EopzNup-OCOxn7tPSBC_F1vw3GZogGAYAHmIaRJw&num=3&cid=5Ggym_HYD_EAThyTRiPFVmUM&sig=AOD64_2j2IfEgci1Fpe5eGlCAmxyQbOIuQ&client=ca-pub-6409535612800042&adurl=http://www.clinlife.mx/lpg/1296/1http://www.googleadservices.com/pagead/aclk?sa=L&ai=C5Q3gGRJeUdaeJ_PCwQHOwoDwBdi8w7kD8Jyf6EvAjbcBEAMg6Y2pBigDUIaTi8_7_____wFg5dv0hIwWoAHQ-e7YA8gBAakCDN5eMWa0tT6oAwGqBLgBT9A6gzf9MZVc0PEQ74X_QtQ9GeUkX90yUQbVlJI5_EkslOf1Kzb71PCqOfYb4kkbmoQhF8SQxrtOMc7-7Fo4T8AKgeC0xJMC0S5k21D-YOI658ZxREvWE4J4S4794SVcmUHMB3-3feWwwla_6dXuRZqW6SSiVpkLW2lb1vebyx3fvXwAWFeQ8ZUbXit6n-wFTukwhZ9HbqP68RTU7bTyTD_m56EopzNup-OCOxn7tPSBC_F1vw3GZogGAYAHmIaRJw&num=3&cid=5Ggym_HYD_EAThyTRiPFVmUM&sig=AOD64_2j2IfEgci1Fpe5eGlCAmxyQbOIuQ&client=ca-pub-6409535612800042&adurl=http://www.clinlife.mx/lpg/1296/1http://www.googleadservices.com/pagead/aclk?sa=L&ai=C5Q3gGRJeUdaeJ_PCwQHOwoDwBdi8w7kD8Jyf6EvAjbcBEAMg6Y2pBigDUIaTi8_7_____wFg5dv0hIwWoAHQ-e7YA8gBAakCDN5eMWa0tT6oAwGqBLgBT9A6gzf9MZVc0PEQ74X_QtQ9GeUkX90yUQbVlJI5_EkslOf1Kzb71PCqOfYb4kkbmoQhF8SQxrtOMc7-7Fo4T8AKgeC0xJMC0S5k21D-YOI658ZxREvWE4J4S4794SVcmUHMB3-3feWwwla_6dXuRZqW6SSiVpkLW2lb1vebyx3fvXwAWFeQ8ZUbXit6n-wFTukwhZ9HbqP68RTU7bTyTD_m56EopzNup-OCOxn7tPSBC_F1vw3GZogGAYAHmIaRJw&num=3&cid=5Ggym_HYD_EAThyTRiPFVmUM&sig=AOD64_2j2IfEgci1Fpe5eGlCAmxyQbOIuQ&client=ca-pub-6409535612800042&adurl=http://www.clinlife.mx/lpg/1296/1http://www.googleadservices.com/pagead/aclk?sa=L&ai=C5Q3gGRJeUdaeJ_PCwQHOwoDwBdi8w7kD8Jyf6EvAjbcBEAMg6Y2pBigDUIaTi8_7_____wFg5dv0hIwWoAHQ-e7YA8gBAakCDN5eMWa0tT6oAwGqBLgBT9A6gzf9MZVc0PEQ74X_QtQ9GeUkX90yUQbVlJI5_EkslOf1Kzb71PCqOfYb4kkbmoQhF8SQxrtOMc7-7Fo4T8AKgeC0xJMC0S5k21D-YOI658ZxREvWE4J4S4794SVcmUHMB3-3feWwwla_6dXuRZqW6SSiVpkLW2lb1vebyx3fvXwAWFeQ8ZUbXit6n-wFTukwhZ9HbqP68RTU7bTyTD_m56EopzNup-OCOxn7tPSBC_F1vw3GZogGAYAHmIaRJw&num=3&cid=5Ggym_HYD_EAThyTRiPFVmUM&sig=AOD64_2j2IfEgci1Fpe5eGlCAmxyQbOIuQ&client=ca-pub-6409535612800042&adurl=http://www.clinlife.mx/lpg/1296/1http://www.googleadservices.com/pagead/aclk?sa=L&ai=C5Q3gGRJeUdaeJ_PCwQHOwoDwBdi8w7kD8Jyf6EvAjbcBEAMg6Y2pBigDUIaTi8_7_____wFg5dv0hIwWoAHQ-e7YA8gBAakCDN5eMWa0tT6oAwGqBLgBT9A6gzf9MZVc0PEQ74X_QtQ9GeUkX90yUQbVlJI5_EkslOf1Kzb71PCqOfYb4kkbmoQhF8SQxrtOMc7-7Fo4T8AKgeC0xJMC0S5k21D-YOI658ZxREvWE4J4S4794SVcmUHMB3-3feWwwla_6dXuRZqW6SSiVpkLW2lb1vebyx3fvXwAWFeQ8ZUbXit6n-wFTukwhZ9HbqP68RTU7bTyTD_m56EopzNup-OCOxn7tPSBC_F1vw3GZogGAYAHmIaRJw&num=3&cid=5Ggym_HYD_EAThyTRiPFVmUM&sig=AOD64_2j2IfEgci1Fpe5eGlCAmxyQbOIuQ&client=ca-pub-6409535612800042&adurl=http://www.clinlife.mx/lpg/1296/1http://googleads.g.doubleclick.net/aclk?sa=L&ai=Cbt6wGRJeUdaeJ_PCwQHOwoDwBdaV_p0D9r_SxD_AjbcBEAIg6Y2pBigDUJWK_IAHYOXb9ISMFsgBAagDAaoEsgFP0EqPHv0wlVzQ8RDvhf9C1D0Z5SRf3TJRBtWUkjn8SSyU5_UrNvvU8Ko59hviSRuahCEXxJDGu04xzv7sWjhPwAqB4LTEkwLRLmTbUP5g4jrnxnFES9YTgnhLjv3hJVyZQcwHf7d95bDCVr_p1e5FmpbpJKJWmQtbaVvW95vLHd-9fABYV5DxlRteK0qce0i9zRCEsaIqhPv3B9IHtxuNP-bloWhzM26nY8IrDP5g_2UAgAfk294K&num=2&sig=AOD64_1to9umlB-WeEKrPEduuzLc5gw0Xg&client=ca-pub-6409535612800042&adurl=http://www.alibaba.com/premium/voltage_transformer.html%3Fsrc%3Dgoogle%26albch%3Dgoogle%26albcp%3Dcontent_content-old%26albkw%3Dvoltage%2520transformer_Others-Top-Content-Product10-P4P_none_none%26albag%3Dpl_none_voltage%2520transformer_product%26albmt%3Dbroad%26albst%3Dcontent-text%26albom%3DOthers-Top_none_20120827_P4P%26creative%3D16984096494%26placement%3Dwww.brighthubengineering.com%26ptsid%3D1012000032308576%26crea%3D16984096494%26plac%3Dwww.brighthubengineering.com%26netw%3Dd


6/32

Primary Winding Current = (Secondary Volts Secondary Current) (Primary Volts

Efficiency), the average value for the efficiency of any transformer nay be presumed to be

0.9 as a standard figure.

Number of Turns = TPV Primary Volts

Primary Winding Area = Number of Turns / Turns per Sq. cm (from the table A)

Reading Table A is easy just find out the relevant figures (wire SWG and Turns per

sq.cm.) by tallying them with the closest matching value of your selected primary current.

Secondary Winding Calculations

As explained above, with the help ofTable A you should be able to find the SWG of the

wire to be used for the secondary winding and the TPV simply by matching them with the

selected secondary current.

The Number of turns for the secondary winding is also calculated as explained for the

primary winding, however considering high loading conditions of this winding, 4 % extra

turns is preferably added to the over all number of turns. Therefore the formula becomes:

Secondary Number of Turns = 1.04 (TPV secondary voltage),

Also secondary winding area = Secondary Turns / Turns per sq. cm. (from table A).

Calculating the Core Size of the Steel Laminations or the Stampings

The core size of the steel stampings to be used may be easily found from Table B by

suitably matching the relevant information with Total Winding Area of the transformer. The

Total Winding Area thus needs to be calculated first, its as follows:

Total Winding Area = (Primary Winding Area + Total Secondary Winding Area) Space for

External Insulation.

The third parameter i.e. the space for the insulation/former etc. may be taken

approximately 25 to 35 % of the sum of the first two parameters.

Therefore, the above formula becomes:


7/32

Total Winding Area = (Primary Winding Area + Total Secondary Winding Area) 1.3

Normally, a core having a square central pillar is preferred and

used - other factors involved are also appropriately illustrated in the adjoining figure and

calculated as follows:

Gross Core Area = Core Area from Table B / 0.9 (sq.cm.)

Tongue Width = Gross Core Area (cm)

After calculating the Tongue Width, it may be used as a reference value and matched

appropriately in Table B to acquire the actual CORE TYPE.

Your quest regarding how to make a transformer gets over when you finally finish

calculating the stack height, using the formula:

Stack Height = Gross Core Area / Tongue Width.

Table A

The table below helps you to select the gauge and turns per sq. cm of copper wire by

matching them with the selected current rating of the winding appropriately.

SWG------- (AMP)------- Turns per Sq.cm.

10----------- 16.6---------- 8.7

11----------- 13.638------- 10.4

12----------- 10.961------- 12.8

13----------- 8.579--------- 16.1

14----------- 6.487--------- 21.5
http://img.bhs4.com/94/4/944284d6d3c6953e60bbde40d12fe9b0f7d88589_large.jpg


8/32

15----------- 5.254--------- 26.8

16----------- 4.151--------- 35.2

17----------- 3.178--------- 45.4

18----------- 2.335--------- 60.8

19----------- 1.622--------- 87.4

20----------- 1.313--------- 106

21----------- 1.0377-------- 137

22----------- 0.7945-------- 176

23----------- 0.5838--------- 42

24----------- 0.4906--------- 286

25----------- 0.4054--------- 341

26----------- 0.3284--------- 415

27----------- 0.2726--------- 504

28----------- 0.2219--------- 609

29----------- 0.1874--------- 711

30----------- 0.1558--------- 881

31----------- 0.1364--------- 997

32----------- 0.1182--------- 1137

33----------- 0.1013--------- 1308

34----------- 0.0858--------- 1608

35----------- 0.0715--------- 1902


9/32

36----------- 0.0586---------- 2286

37----------- 0.0469---------- 2800

38----------- 0.0365---------- 3507

39----------- 0.0274---------- 4838

40----------- 0.0233---------- 5595

41----------- 0.0197---------- 6543

42----------- 0.0162---------- 7755

43----------- 0.0131---------- 9337

44----------- 0.0104--------- 11457

45----------- 0.0079--------- 14392

46----------- 0.0059--------- 20223

47----------- 0.0041--------- 27546

48----------- 0.0026--------- 39706

49----------- 0.0015--------- 62134

50----------- 0.0010--------- 81242

Table B

This Table B enables you to make your own transformer design by comparing the

calculated Winding Area with the relevant required Tongue Width and Lamination Type

number.

Type-------------------Tongue----------Winding

No.---------------------Width-------------Area

17(E/I)--------------------1.270------------1.213


10/32

12A(E/12I)---------------1.588-----------1.897

74(E/I)--------------------1.748-----------2.284

23(E/I)--------------------1.905-----------2.723

30(E/I)--------------------2.000-----------3.000

21(E/I)--------------------1.588-----------3.329

31(E/I)--------------------2.223-----------3.703

10(E/I)--------------------1.588-----------4.439

15(E/I)-------------------2.540-----------4.839

33(E/I)--------------------2.800----------5.880

1(E/I)----------------------2.461----------6.555

14(E/I)--------------------2.540----------6.555

11(E/I)---------------------1.905---------7.259

34(U/T)--------------------1/588---------7.259

3(E/I)-----------------------3.175---------7.562

9(U/T)----------------------2.223----------7.865

9A(U/T)----------------------2.223----------7.865

11A(E/I)-----------------------1.905-----------9.072

4A(E/I)-----------------------3.335-----------10.284

2(E/I)-----------------------1.905-----------10.891

16(E/I)---------------------3.810-----------10.891

5(E/I)----------------------3.810-----------12.704


11/32

4AX(U/T) ----------------2.383-----------13.039

13(E/I)--------------------3.175-----------14.117

75(U/T)-------------------2.540-----------15.324

4(E/I)----------------------2.540----------15.865

7(E/I)----------------------5.080-----------18.969

6(E/I)----------------------3.810----------19.356

35A(U/T)-----------------3.810----------39.316

8(E/I)---------------------5.080----------49.803


12/32

Kapp regulation diagram

From Encyclopedia Magnetica

Jump to:navigation,search

S. Zurek,Kapp regulation diagram,Encyclopedia Magnetica, {accessed 6 Apr 2013}

edited 1 Jan 2012 1 Feb 2013 reviewedbyJ. Leichton 1 Feb 2013

Kapp regulation diagram[1]

fot. S. Zurek, Encyclopedia Magnetica, license: CC-BY-3.0

Kapp regulation diagram - a graphical method of determining thevoltage regulationin a

transformercaused by changes inloadandpower factor.[1]

The output voltage of a mainspower transformerwhen loaded reduces for inductive load (power

factor lagging) and increases for capacitive load (power factor is leading).

The Kapp diagram is helpful in finding the voltage drop or increase (voltage regulation). The main

disadvantage is that the voltage regulationphasorsare much smaller than the radii of the main

circles, so the diagram has to be drawn on a very large scale to get sufficiently accurate results.[1]
http://magnetica.shoutwiki.com/wiki/Kapp_regulation_diagram#mw-headhttp://magnetica.shoutwiki.com/wiki/Kapp_regulation_diagram#mw-headhttp://magnetica.shoutwiki.com/wiki/Kapp_regulation_diagram#mw-headhttp://magnetica.shoutwiki.com/wiki/Kapp_regulation_diagram#p-searchhttp://magnetica.shoutwiki.com/wiki/Kapp_regulation_diagram#p-searchhttp://magnetica.shoutwiki.com/wiki/Kapp_regulation_diagram#p-searchhttp://magnetica.shoutwiki.com/wiki/User:Stan_Zurekhttp://magnetica.shoutwiki.com/wiki/User:Stan_Zurekhttp://magnetica.shoutwiki.com/http://magnetica.shoutwiki.com/http://magnetica.shoutwiki.com/http://magnetica.shoutwiki.com/wiki/Help:Articles_with_reviewhttp://magnetica.shoutwiki.com/wiki/Help:Articles_with_reviewhttp://magnetica.shoutwiki.com/wiki/User:Jeanete_Leichthttp://magnetica.shoutwiki.com/wiki/User:Jeanete_Leichthttp://magnetica.shoutwiki.com/wiki/User:Jeanete_Leichthttp://magnetica.shoutwiki.com/wiki/Kapp_regulation_diagram#cite_note-Rajput-0http://magnetica.shoutwiki.com/wiki/Kapp_regulation_diagram#cite_note-Rajput-0http://magnetica.shoutwiki.com/w/index.php?title=Voltage_regulation&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Voltage_regulation&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Voltage_regulation&action=edit&redlink=1http://magnetica.shoutwiki.com/wiki/Transformerhttp://magnetica.shoutwiki.com/wiki/Transformerhttp://magnetica.shoutwiki.com/w/index.php?title=Load&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Load&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Load&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Power_factor&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Power_factor&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Power_factor&action=edit&redlink=1http://magnetica.shoutwiki.com/wiki/Kapp_regulation_diagram#cite_note-Rajput-0http://magnetica.shoutwiki.com/wiki/Kapp_regulation_diagram#cite_note-Rajput-0http://magnetica.shoutwiki.com/wiki/Kapp_regulation_diagram#cite_note-Rajput-0http://magnetica.shoutwiki.com/w/index.php?title=Power_transformer&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Power_transformer&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Power_transformer&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Phasor&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Phasor&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Phasor&action=edit&redlink=1http://magnetica.shoutwiki.com/wiki/Kapp_regulation_diagram#cite_note-Rajput-0http://magnetica.shoutwiki.com/wiki/Kapp_regulation_diagram#cite_note-Rajput-0http://magnetica.shoutwiki.com/wiki/Kapp_regulation_diagram#cite_note-Rajput-0http://magnetica.shoutwiki.com/wiki/File:Kapp_regulation_diagram_Magnetica.svghttp://magnetica.shoutwiki.com/w/index.php?title=File:Kapp_regulation_diagram_Magnetica.svg&page=1http://magnetica.shoutwiki.com/wiki/File:Kapp_regulation_diagram_Magnetica.svghttp://magnetica.shoutwiki.com/w/index.php?title=File:Kapp_regulation_diagram_Magnetica.svg&page=1http://magnetica.shoutwiki.com/wiki/Kapp_regulation_diagram#cite_note-Rajput-0http://magnetica.shoutwiki.com/w/index.php?title=Phasor&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Power_transformer&action=edit&redlink=1http://magnetica.shoutwiki.com/wiki/Kapp_regulation_diagram#cite_note-Rajput-0http://magnetica.shoutwiki.com/w/index.php?title=Power_factor&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Load&action=edit&redlink=1http://magnetica.shoutwiki.com/wiki/Transformerhttp://magnetica.shoutwiki.com/w/index.php?title=Voltage_regulation&action=edit&redlink=1http://magnetica.shoutwiki.com/wiki/Kapp_regulation_diagram#cite_note-Rajput-0http://magnetica.shoutwiki.com/wiki/User:Jeanete_Leichthttp://magnetica.shoutwiki.com/wiki/Help:Articles_with_reviewhttp://magnetica.shoutwiki.com/http://magnetica.shoutwiki.com/wiki/User:Stan_Zurekhttp://magnetica.shoutwiki.com/wiki/Kapp_regulation_diagram#p-searchhttp://magnetica.shoutwiki.com/wiki/Kapp_regulation_diagram#mw-head


13/32

Drawing algorithm

In order to create the diagram it is necessary to know the equivalentreactanceX02 andresistanceR02

of the transformer asreferredto thesecondary side. The following algorithm should be used:

1. DrawphasorOL representing secondary terminal voltage V2 on load2. Draw OXrepresenting the phase of the secondary current at an angle2 to OL such that

cos2 is the power factor of the load

3. Draw phasor LM (I2 R02 - voltage drop on resistance referred to the secondary side) parallelto OX, and then MN(I2 X02 - voltage drop on reactance referred to the secondary side).

The resulting NL is the total voltage drop.

4. Transfer the impedance triangle NLM to OO'Pwhich gives O'L = ON= 0V2. Therefore, forgiven secondary current thelocusofNis a circle with centre O and radius 0V2, while the

locus ofL has the same radius but with the centreO'

5. To find the voltage drop on full load at any power factor the radius OQS should be drawn

at at angle to OX. If the impedance triangle is drawn in position UQTthen OU= OS. Thelength ofQS represents the voltage drop.

References
http://magnetica.shoutwiki.com/w/index.php?title=Reactance&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Reactance&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Reactance&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Resistance&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Resistance&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Resistance&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Referring&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Referring&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Referring&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Secondary_side&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Secondary_side&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Secondary_side&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Phasor&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Phasor&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Phasor&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Locus&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Locus&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Locus&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Locus&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Phasor&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Secondary_side&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Referring&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Resistance&action=edit&redlink=1http://magnetica.shoutwiki.com/w/index.php?title=Reactance&action=edit&redlink=1


14/32

Making a welder out of an old transformer.

Seeing the post a while back about the burnt out 3 phase

transformer has got

me thinking again.

After getting my old Forney welder, I have been playing around

with seeing

how hard it really is to design your own welder to operate the

way you want

it too. That has led me to experiments with a couple old 480V

to 120/240

volt transformers I have.

I have decided to post a little article on possible methods to

convert anold transformer into a welder. Opinions on my ideas is welcome.

This post will be very long.

The type of transformer you are looking for is one with a large

open core. A

single phase with two coils on a single donut core (two leg). Or

a three

phase one with three windings and three legs that are bridged at

the top and

bottom (three leg).

Those types have a large core that will have a lot of flux

leakage when

driven by only one leg.

Transformers that have the E-I core with the return path going

around both

sides of a single winding have very little flux leakage and you

will have a

problem designing a reasonable current limited transformer out

of it.

You get the current limiting action by arranging the windings on

the core so

that there is a large leakage path between them. The farther

apart you have


15/32

the primary and secondary, the more flux leakage. The closer you

have them

located, the leakage and you will get less of a current limiting

action.

The primary produces flux when it energized. That flux tries totake the

easiest path to form a loop. Be it steel, air, or water. The

easiest path

for it to take is steel, when the coil is wound around a steel

donut, then

the magnetic flux generally prefers to go through that steel

donut to form a

loop. Path of least resistance. But if you put a shorted coil on

the other

side of the loop, then it stops the flux from passing throughthe complete

donut. The flux will jump across the middle of the donut between

the primary

and secondary to complete the flux loop. Longer, and narrower

the gap that

the flux has to jump across, the more counter EMF the secondary

has to

generate to force the primary EMF to jump that gap.

A tall but narrow donut with the primary on the right and

secondary on the

left leg. With the primary and secondary side by side. It will

take more amp

turns in the secondary to get the primary flux to bypass the

secondary.

If you have a wide but short donut with the primary and

secondary on the

right and left leg, the gap between the primary and secondary is

large. Then

the gap between the top and bottom part of the donut where the

flux has to

jump is short and wide. It takes a lot less current in the

secondary to

force the primary flux to jump the gap between the primary and

secondary.


16/32

And example of a simple transformer for making a welder.

A 240/480 to 120/240 single or three phase transformer.

Single phase has....

One 240V primary and a 120V secondary on each leg. The primaries

are stungin series for 480V or in parallel for 240V. The secondary

windings are in

series for 120/240 center tapped. Or can be put in parallel for

120V. Often

the secondary windings are split between the legs to even out

loading, and

reduce leakage. That means that there is two 60V secondary

windings on each

side that is in series with the opposed one on the other side.

Three phase with three legs that are bridged at the top and

bottom. Each leg

has one primary and one secondary. wye or delta on primary and

secondary

If you are lucky, there is enough room between the existing

coils to wind

your custom windings.

If it is tightly packed, then you may have to remove all, or

part of, the

windings on one side to make room for your custom windings..

Pick a coil/side/leg for your primary. If you have a transformer

that has a

mixture of damaged windings and good ones, then pick a good one.

It should

have a 208,240 277, or 480V primary and one or more secondary

windings on

that leg of the transformer.

Remove the damaged windings. Then start experimenting.

Example. (from the experiments I did with one of my

transformers. 15KVA

240/480 to 120/240 single phase) Your transformer has a 240V

primary on each


17/32

leg. Hook 120V to one primary. Run a single turn or a couple

turns around

the core and measure the voltage across it. If you have three

turns and you

get 3.6V AC then your transformer is running at 1.2V per turn.

Sincedesigned operating voltage for the transformer is twice what you

have the

primary hooked too, then designed operating level will be 2.4V

per turn.

When testing, you want to leave the transformer hooked to the

lowest

exciting voltage you have, that will make the testing safer, and

the

currents developed for that core the lowest possible.

Lets say that you have the above stated situation. 120V hooked

to a 240V

winding which yields you a 1.2V per turn. On a single phase

transformer.

That tells you that the primary on each leg has 100 turns.

Some will have a secondary by it's self on each leg that has 50

turns.

Some single phase transformers will have each secondary split

between both

legs, so you have two 25 turn secondary windings on each leg.

When you have the one primary excited with 120V you will have

120V on the

other primary and 60V or two 30V on the secondary windings on

each leg.

Now to find out the current characteristics of your transformer.

There is two factors that limit current in the setup. The

conductor

resistance. And the flux leakage. Conductor resistance makes the

windings

hot, so we want the windings big enough that that isn't a

factor.


18/32

Lets say that your transformer has an available current of

2040Amp turns

into a shorted leg when the other leg is excited by 120V.

If you had a single turn large enough to handle that current on

that legthen you would have close to 2040A on that turn when it's

shorted, or 1.2V

when it's open.

(If you made that single turn with a 4 foot piece of 10g wire,

the current

would be limited by the wires resistance. 1.2V across 4 feet of

wire is

close to 300 amps. The wire will get hot very quickly. The wire

will begiving in, not the flux in the transformer. The voltage across

the leg doesn't

drop, the wire is just forced to drop the voltage across it's

length.)

Lets continue with that train of though.

If you had two turns of wire adequate for the current, you would

get 2.4V

when open, and 1020A when closed. That would be in about the

right range for

spot welding, but not for arc welding. So lets continue on.

10 turns would yield 12V at 204A

20 turns would yield 24V at 102A close but not quite.

30 turns would yield 36V at 68A getting real close to the right

voltage.

40 turns yield 48V which does quite well at 51A with the 1/16

6013 rod.

50 turns yields 60V that also does quite well at around 41A

Considering that the two low voltage windings I have are 25

turns each. I


19/32

can have one winding plus 15 more turns of wire with it to get

40 turns, or

use both in series to get 50 turns.

So, my transformer without major modification can serve as a 40

or 50awelder with the addition one 15 turns of wire on one side. You

could use the

other unused 100 turn primary on that side for a 120V OC 20A

welder. Now if

I could only find 1/32 welding rod! :-)

For the secondary windings left over on the side that you are

driving as the

primary. since they are in the same coil as the driven primary,

there willbe no real current limiting. So you could use them as a CV

output to drive a

mig gun, If you hook them in parallel for 30V. Considering that

my

transformer is rated at 15KW you should have 120A continuous

duty on hand to

drive that mig gun.

That is what you could do with a very simple winding

arrangement.

Now, lets get to the complex winding arrangements for an arc

welder.

Lets go for a base 50V OC on all outputs.

Lets hook up the two secondary windings on the output (current

limited) side

in parallel so that we have 30V OC with a short circuit output

of 81A that

will allow us to make use of what is already there.

Take that as are base winding. The winding can handle up to 120A

continuously (two 60A windings in parallel)

For are 50A tap, run are base winding in series with 16

additional turn new


20/32

winding. That yields 49V at close to 50A

For the 40A tap, we can't just use a 25 turn tap in series with

the base

winding because that will yield 60V OC. Remember we want a

nominal 50V OC.Here is where we get into the complex windings.

To do that, we have to have the additional 25 turn winding in

series with a

buck winding on the primary driven side. A buck winding on the

primary side

is close coupled with the driven winding so it will reduce the

output

voltage but it won't reduce the current available at the output

since therewon't be any current limiting action.

So, you will have a winding with 25 turns on the current limited

side plus 8

reverse turns on the driven side. That will yield you 40A at 50V

OC. (you

get the output current from 50 turns on the current limited

side, and you

use 8 buck turns to get the voltage down to spec) Now, it won't

be exactly

that because with the buck winding, you are not directly

shorting the

current limited side. So you may have to take a winding may have

to take a

turn off of each side until current comes up to spec for that

tap.

Now lets go for the 60A tap.

Lets take the base winding and add a 9 turn new winding to the

current

limited side.(9 turns of the new 15 turn winding for the 50A

tap) And run

that to a 7 turn boost winding on the primary driven side. That

will get you

60A at 50V. (34 turns on the current limited side plus 7 boost

turns)


21/32

The highest we could wind this transformer for is 70A and still

maintain

100% duty cycle, which would be 29 current limited turns plus 12

boost

turns. (base winding plus 4 with 12 boost turns)

Now if we went with interment ant duty we could easily go 80A

which is the

base winding plus 12 boost windings. In actuality, that setup

would be

closer to 100A or higher because the current limited winding

will be driven

beyond shorted. It will actually be driven reverse polarity. (0V

- boost

voltage)

So, just experiment and move the winding around till you find

the current

you want.

You can tailor it to get about any OCV you want. If you want a

digging arc

or a rubbery arc, you can tailor it to fit your desires.

To get 100A out, at 50 OCV you will want to run it on a 50A 120V

breaker.

If you drive the primary at full rated 240V you will have to

arrange the

secondary and buck boost windings to compensate for a higher

amp turns that

is available on the current limited side, plus the additional

volt turns.

"Now wait a second" you say "how does all that help me find out

how much

current my transformer will put out?????????"

Well. Put some test windings on your transformer and Either run

you selected

transformer primary off of 120V or even 60Vor 30V from another


22/32

transformer.

Have a current meter on the test windings and short them out for

a second to

see what you get. Rearrange the test windings and try again.

When you get the current down to a relatively low level at 30 or60 V then

you can step up to the next drive voltage level and check what

affect that

has. Rearrange the windings, and step up another voltage level.

I would not suggest that you power the selected primary to full

rated

voltage and then short a test winding on it with no prior

knowledge of the

transformer in question. You may be in for a little bit morecurrent than

you bargained on. Plus a lot of melted wires to boot.

One way of bringing up the power level more gradually is use a

large variac

to slowly bring up the voltage level on a shorted test winding

and see where

the current levels off. You will be able to see if the current

is climbing

way faster than you anticipated with the voltage, and if you

will need to

change your winding layout before bringing it to full voltage.

If you have a transformer that you have taken one of the coils

off one of

the legs, then you will have a lot more freedom to arrange the

windings.

If you have a three phase transformer with two bare legs then

that opens up

a world of possibilities. When you short a winding out on one

leg, then the

flux will shift to the other leg. You could use one winding on

one leg as an

output winding and have a winding on the other that is connected

to SCR's to

vary the current. When the SCR's are full on, then it forces all


23/32

the current

to the output winding, and when they are full off, then none of

the current

is forced to the output. (it bypasses the output winding through

the open

SCR winding)Don't forget the secondary windings on the drive leg. They can

be run in

series with the primary to reduce the volts turn drive level at

a specified

supply voltage!!!

Now it is getting late, and I am getting tired, so I am going to

wrap this

up and post it to see what you people think.


24/32

CURSO DE SOLDADURA SMAW (11)

20:15 No comments

Capitulo 11: MAQUINAS DE SOLDAR (transformador).

Aparato elctrico que transforma la corriente elctricabajando la tensin de la red de alimentacin a unatensin e intensidad adecuada para soldar. Dicha CAde baja tensin (65 a 75 voltios en vaco) y deintensidad regular. Permite obtener la fuente de calornecesaria para la soldadura.

El transformador consta de un ncleo que estcompuesto por lminas de acero al silicio y de dosbobinas de alambre; el de alta tensin, llamadoPRIMARIO y el de baja tensin llamadoSECUNDARIO.

La corriente que proviene de la lnea circula por

el primario.

Los transformadores se construyen paradiferentes tensiones, a fin de facilitar su conexin, entodas las redes de alimentacin.

La transformacin elctrica se explica de la formasiguiente: "La corriente elctrica que circula por el

primario genera un campo de lineas de fuerzamagntica en el ncleo, dicho campo actuando sobrela bobina secundaria, produce en este, una corrientede baja tensin y alta intensidad, la cul se aprovechapara soldar.
http://weldermex.blogspot.mx/2012/08/curso-de-soldadura-smaw-11.htmlhttp://weldermex.blogspot.mx/2012/08/curso-de-soldadura-smaw-11.htmlhttp://weldermex.blogspot.mx/2012/08/curso-de-soldadura-smaw-11.html#comment-formhttp://weldermex.blogspot.mx/2012/08/curso-de-soldadura-smaw-11.html#comment-formhttp://weldermex.blogspot.mx/2012/08/curso-de-soldadura-smaw-11.html#comment-formhttp://weldermex.blogspot.mx/2012/08/curso-de-soldadura-smaw-11.html


25/32

CARACTERSTICAS

La regulacin de la intensidad se hacecomnmente por dos sistemas:

1- Regulacin por bobina desplazante: Consisteen alejar el primario y el secundario

entre s.

Observacin: Esta sistema es recomendable por

su regulacin gradual.

2- Regulacin por clavija: Funciona aumentandoo disminuyendo el nmero de espiras.
http://2.bp.blogspot.com/-yq5pZkKTmPk/UDROYNSGFLI/AAAAAAAAAMA/JPJtM--rqU8/s1600/maquinas-de-soldar-transformador_25815_11_2.JPGhttp://1.bp.blogspot.com/-JxUMa-jSzOk/UDRNhVsOAZI/AAAAAAAAAL4/JId5xwkDBfs/s1600/maquinas-de-soldar-transformador_25815_11_1.JPGhttp://2.bp.blogspot.com/-yq5pZkKTmPk/UDROYNSGFLI/AAAAAAAAAMA/JPJtM--rqU8/s1600/maquinas-de-soldar-transformador_25815_11_2.JPGhttp://1.bp.blogspot.com/-JxUMa-jSzOk/UDRNhVsOAZI/AAAAAAAAAL4/JId5xwkDBfs/s1600/maquinas-de-soldar-transformador_25815_11_1.JPG


26/32

Los transformadores se conocen tambin comoMAQUINAS ESTATICAS por no tener piezas mviles.

VENTAJAS

El uso del transformador se ha generalizado por:

-4- Bajo costo de adquisicin

-5- Mayor duracin y menor gasto demantenimiento

-6- Mayor rendimiento y menor consumo envaco

-7- Menor influencia del soplo magntico

DESVENTAJAS

Entre sus desventajas se pueden mencionar:

-8- Limitacin en el uso de algunos tipos deelectrodos

-9- Dificultad para establecer y mantener elarco
http://4.bp.blogspot.com/-JX5gtuZaoC0/UDROk_wSFAI/AAAAAAAAAMI/EN2GrxPEj0E/s1600/maquinas-de-soldar-transformador_25815_11_3.JPG


27/32

MANTENIMIENTO

Debe mantenerse el equipo libre de polvo yhumedad

PRECAUCIN

Toda accin de limpieza debe efectuarse con lamquina desconectada

Al instalarla debe elegirse un lugar seco fijandoen la mquina, una conexin a tierra.

ACTIVIDAD

27- Nombre las dos formas para regular elamperaje en las mquinas estticas

28- Cules son los principales componentes deuna mquina esttica y a que se debe su nombre.


28/32

TRANSFORMER DESIGN, CONSTRUCTION & THEORY

Presented here is an overview of transformers for hobbyists that want to expandtheir knowledge of this essential electrical component.

Of the 3 basic passive electrical components, R, L, C, the transformer is simply aspecial case of the inductor with either taps or multiple windings that are coupled.

It will operate over the full range of frequencies and may be either iron or aircored; most of the following discussions will concentrate on low frequency, iron

cored transformers.

The basic transformer to be discussed is the voltage (or power transformer), whichoperates at mains frequency and is step up or down. There are also special cases,

such as current transformers, pulse transformers and audio (output and driver)types that cater for a wider band of frequency.

3 phase transformers are simply a special case of the single-phase transformer

with the core arranged to give a balanced magnetic circuit.

Transformers consist of a core and windings; the core is usually an iron alloy tosuit the application and the windings consist of coils of insulated copper or

aluminium wire.

There is no absolutely correct design for any given transformer; as in all matters ofgood engineering there are many design and cost compromises to be made.

Having selected a core and decided on a flux density, the T/V figure is calculatedand then it is a matter of seeing if the turns will fit on the bobbin available for the

selected core.

THE CORE

All transformers follow the basic transformer equation and work by reason of thefact that the magnetic flux, produced by the primary applied voltage is constantly

changing. This is basic magnetic theory. It appears confusing as it is taught inmany systems of units. I will concentrate on the MKS system where the units are

Metres. DO NOT USE mm!!!This is a practical system where the unit of flux density is the TESLA. Normaltransformers operate at levels around 1T depending on the materials used.

Transformer equation:

N = E / 4.44 B F Ae Where:

N = turns


29/32

E = applied voltage in volts4.44 is a constant for sine wavesB = desired flux density in Tesla

F = frequency in HzAe = transformer centre limb area in M

Stalloy or silicon iron, which is widely used as a core material is normally operatedat a flux density of 1T. Unisil, a grain orientated material, which is a little more

expensive can be run at 1.5 T. Special alloys for Mil and aerospace applications canbe run up to 2T where a compact design is a requirement.

Running at a higher flux density allows the turns/ volt to be reduced and the costof copper and copper losses; however this increases the losses in the iron andincreases the magnetising (idling) current. Design curves are available showing

watts loss per Kg at various flux densities.Traditional design theory would make copper and iron losses equal at normal load

levels (say 80% of full load)

An important fact of life with iron cores is Saturation. When we increase thevoltage across an iron cored coil the current will initially increase in a linear

manner. When we reach a certain level the current will start to increase muchmore rapidly than the voltage. This is the Knee point where a lot of transformers

are designed to operate.Note that Stalloy has a fairly rapid turn into saturation, Unisil much less so. Hence

lower distortion when used in the output transformer of a Hi-Fi amplifier.

To determine the operating level of an unknown core it is simply a matter ifwinding a know number of turns onto the core, and then plotting a V/A curve. At

the point at where it starts to turn into saturation will be the operating level, and itis then easy to read off the Turns/Volt from the plot.

Other core losses are determined by the circulation of eddy currents in thelaminations. Thinner lams and lower frequencies give lower losses, but increase

the cost of the lams. A solid core would have very high losses, hence the lams arelightly oxidised to give insulation between them. These losses are frequency

dependant.Most laminations available these days are lossless types.

This means that they are E & I shapes stamped out of sheet so as to leave nowaste. Many other forms will be encountered in vintage equipment.

Transformers should normally be laminated to leave as small a gap between lamsas possible, interleaving and tapping them together during assembly. The

exception to this is transformers carrying DC, as in Class A valve output stages,where the standing DC current could cause saturation and a small air gap, usually

made from thin paper is inserted between the E & I lams that are not nowinterleaved.


30/32

Clamping bolts, when inserted through the lams should have an insulation washerbetween the lam face and the nuts. If this is not done there can be high currents

circulating through the bolt.

Toroidal transformer cores can be run at higher flux densities and have the

advantage of a much lower stray field, useful in audio applications

THE WINDINGS

These are usually of enamelled copper wire but various other insulations areavailable. The insulation should be as thin as possible consistent with a suitable

electrical withstand level. Windings often had a thin layer of paper between layersof winding. With present wire insulation this is not necessary every layer, and is

often replaced with Type 56 Polyester tape every few layers, again depending onapplication.

The normal wire current density is typically 3A per mm and this figure is oftenshown in wire tables.

Note that wire sizes, in SWG, AWG or mm are based on bare wire, not coateddiameter.

The current density figure is based on a max internal temperature for thetransformer of 120C; the limit for normal materials, other design factors may

dictate different values.Wire tables will also give the resistance/ Mtr of wire. This is used to calculate the

winding resistance from the mean length of turn. Note that copper resistivityincreases by 0.3% per C rise.

The transformer equation gives the primary turns; secondaries can then becalculated by the turns ratio. If very exact ratios are required it may be necessary

to increase the primary turns so as to get an integral number of turns on thesecondary of importance.

If an exact voltage is required it is often necessary to add compensating turns to asecondary to allow for the volt drops (calculated from mean length of turn and

resistance per mtr) in both primary and secondary.It can also be necessary to allow for the increase of resistance due to temperature

rise as well.Further compensation is sometimes necessary to allow for the imperfect coupling

between primary and secondary which appears as a parasitic loss.

Primaries and secondaries are normally wound on top of each other for goodcoupling; where additional safety separation is required, they may be wound side

by side with a centre insulated barrier (some transformer kits with pre-wound


31/32

primaries are like this).This gives inferior coupling and additional compensating turns will be needed to

compensate for this.For very close coupling the primary and secondary will be wound together with Bi-filar wire. Where insulation levels make this impossible, the primary and secondary

are wound in several sections, one on top of the other. For balance this wouldusually be one more primary section than secondary section.

Wire is commonly insulated with synthetic enamels in either 1 or 2 coats. Mostmodern enamels can be vaporised with solder and are known as solderable types.

Where high levels of insulation are required in a small space (such as a switchmode transformer), then triple insulated wire can be used. This is certified for

supply to low voltage windings without additional insulation.

An earthed copper screen is often placed between the primary and secondary; thisis for both safety and as an interference screen against noise impulses.

Windings are not normally carried to the outside of the bobbin on multi-layerwindings due to the danger of a turn slipping down the side of the bobbin and

seeing a higher voltage, possibly causing breakdown. Paper margin tapes, a fewmm wide are often used here.

With EHT transformers this margin is often tapered inwards (wider) as the outerlayers are added and the winding voltage to earth increases.

Copper is the important part of the winding so thin insulation is used, as there isonly a relatively low voltage between turns and layers. This is usually capable of

withstanding a minimum of 120C.

The windings are often vacuum impregnated to seal against moisture and preventchafing movement under operating or fault conditions. It is possible to sprayvarnish them while building, or they can be paraffin wax impregnated in a

container of molten wax.For voltages above 6KV it is usual to seal the transformer in a can of specially

refined mineral oil.

Tapping points on windings can be brought out of the body of the winding bylooping the wire out and back again. Lead-out wires are often soldered on to the

winding at an appropriate point. These must be well insulated.

The forgoing should allow a reasonably competent person to design and build theirown transformers when size and cost are not the driving factors as in commercialapplications. It should always be remembered that these devices are connected tothe mains and can easily kill or start serious fires; all possible safety precautions

should be taken when using them.


32/32

Ed Dinning 2009

Apuntes Sobre Maquinas de Soldar

Documents

Transcript of Apuntes Sobre Maquinas de Soldar