584,800 active members*
4,852 visitors online*
Register for free
Login
Page 15 of 16 513141516
Results 281 to 300 of 305
  1. #281
    Join Date
    Jul 2010
    Posts
    0

    Induction Furnace

    Hi guys and Gals if there is any.

    I am an absolute newbie to this forum and has no clue on how an induction furnace works.

    History:I am an keen electronic hobbiest and like figuring stuff out by myself.If and IF induction furnace works in any way simular to radio technology then i understand why i did burn my hand years ago on an HF antennae putting out 900watts of RF.

    Back to the present.I have build my own mig welder in the sense of getting hold of burnt out boards from a friend of mine who repair these devices(replacing faulty boards).Repairing these boards for myself and a month later i had my own 250Amp mig welder costing me less than 5 litres of petrol here in South Africa.At full blast with 1.2mm mig wire actually tripping a 40Amp circuit breaker(2X20amps).

    Looking at the circuit of HVGuy at WWW.HVGuy.com the circuit on the mig welder looks pretty much the same with the exception of the work coil on HVGuy's circuit,the half bridge and the rectifiers on the mig welder board.

    Question:Is it possible to convert such a welder to an induction furnace.Please all info will be regarded as valuable.What is the pros and cons converting such a circuit

    My current invertor uses power mosfets but i do have a IGBT and the driver board with the controller.

    Please guys let us share and keep the topic alive

    Kind Regards

    Maxtron

  2. #282
    T3sl4 Guest
    The general circuit is similar for everything: power supplies, inverters, welders, induction heaters, etc. The difference is mostly about how you control it. An induction heater is very sensitive to frequency, so automatic frequency control is valuable. Most power supplies (including welders) are happy at constant frequency, so you will need to make big changes there. The load is reactive, so you need frequency or power control to keep things within ratings at all times. An unloaded work coil can draw a lot of power in some systems, or very little in others. Things like series vs. parallel resonance, and constant voltage vs. constant current drives.

    Tim

  3. #283
    Join Date
    Jul 2010
    Posts
    0
    Thank you for your response T3sl4.
    I am sorry for asking a lot of questions.

    In some circuits i see that the operation frequency is any thing from 2.4Khz-1Mhz.I believe it is for different types of metals.Can you give me more info on that.?

    Another question is,is it possible to supply me a schematic that is simular to a pll system for the frequency to melt alu cans and what will the inductance of the work coil be if my max Current on this machine is like 250Amps at about 60Volts open circuit

    Thanks again for your response.

    Kind Regards
    Maxtron

  4. #284
    T3sl4 Guest
    Jon has lots of information here:
    http://www.mindchallenger.com/induct...duction10.html

    Exact frequency doesn't matter, and depends on what you happen to have for work coil and tank capacitor. What range of frequency you use depends what you'll be heating: very large work (e.g., cast iron holding furnaces) can be heated at 50/60Hz directly; regular sized steel, aluminum and bronze are easy to work with in the 10-100kHz range; powdered metals need higher frequencies around 1MHz; and diathermy and plasma generators require much higher voltages and often run in the 13.56MHz industrial band.

    You can calculate the required capacitor, transformer and current by making some basic assumptions on impedances.

    Q means Quality factor, which tells you how much resonant energy you need for some amount of real power output. A low Q is better because it requires less energy, but is hard to reach for most work, because most work just isn't that lossy. There are some advantages to a higher Q, for instance a series resonant circuit will make up the extra voltage for you.

    Example: assume a Q of 5. This is typical for a bar of steel inside a somewhat larger coil, or a tight-fitting hunk of aluminum.

    Work coils range in value from 0.2 to over 50 microhenry; a reasonable goal to accommodate would be 1-10uH. This exclues small hairpin and few-turn coils, as well as large furnace sized coils. Such coils are a few inches across and have a reasonable number of turns, easy to make from copper tubing.

    A typical frequency is 50kHz. Let's say 50kHz for a 2uH coil. Because F = 1 / (2*pi*sqrt(L*C)), you need C = 1 / (4*pi^2*F^2*L) = 5uF. This might be hard to find because it has to carry over 100A, but smaller capacitors can be used to build one, as I have done. Polyester will melt in this service; use only polypropylene. MKPs are usually good.

    At 50kHz, 2uH has an impedance of 0.63 ohms, so at Q = 5, the effective load resistance will be 0.126 ohms in series, or 3.14 ohms in parallel. Series resonance is easier to drive so I recommend it. The downside is, the total impedance at resonance is only 0.126 ohms, so you must drive it with a very low voltage. For 1kW output, you have V = sqrt(P*R) = 11.2V and I = V/R = 89A to drive. This requires a transformer. If your inverter produces 200Vrms, you need a 200:11 turns ratio.

    Tim

  5. #285
    Join Date
    Apr 2009
    Posts
    7
    Hi all guys! I'm amazed of your work Chistyakov1971!!! how you brace the coil to the furnace frame?

  6. #286
    Join Date
    May 2009
    Posts
    40
    Simple installation of induction heating.
    Laboratory work at chemistry institute.
    Without PLL.
    Levitatsionnaja melting Ti
    rus
    http://www.icct.ru/Practicality/Pape...nvertor-01.php
    http://www.icct.ru/Practicality/Pape...nvertor-02.php

    =========
    The Italian furnace GALONI VCM










    The furnace for stomatologists Krupp HTG1000



  7. #287
    Join Date
    Jul 2010
    Posts
    0

    Bipol Module

    I have come across several bipol modules QM100DY-2H.According to the dataheet it can handle up to 100Ampere at 1000Volts and switching up to a 1000Ampere.I got this for free.Is it possible to use this on a small type induction furnace.Will the drive be more or less the same as on the IGBT's.Maximim base voltage is 7Volts.Can it be driven by high frequency switching transformer.Older Pc Power supply run adequate with Bipol transistors.....

    Kind Regards.
    Maxtron

  8. #288
    Join Date
    Oct 2006
    Posts
    13
    G'day peepz! :wave:

    Once again i've been bitten by the IH bug so heresmy latest project:
    [nomedia="http://www.youtube.com/watch?v=nYsSFf78H-A"]YouTube - Induction heater owns nut[/nomedia]

    Yes its a mess but thats gonna change soon.

  9. #289
    Join Date
    Feb 2010
    Posts
    331
    looks good. seems to work well also.

    one thing. move the off switch close to the machine! if there was an emergency you have to run half way across the house to turn it off! i just dont want to see you melt your foot off with some molten metal.

  10. #290
    Join Date
    Oct 2006
    Posts
    13
    that will come.

  11. #291
    Join Date
    Oct 2009
    Posts
    5
    Quote Originally Posted by rustyolddo View Post
    If anyone is interested I have a copy of the schematics that were originally posted on the hvguy aka Aron Koscho & Justin Hays website (the current website is infected with a virus). They were for a 2.5kW unit. If someone has a way to host them, shoot me an email and I'll email you the whole nine yards, I saved the web page a long time ago for off line viewing. If someone takes the initiative to produce boards for the design, let me know as I'd like to build the unit for heat treating use.
    I would like see what stuff you had saved is it of importence ican produce boards for it i am also intrusted in melting of metals by induction heating


    Siamon99

  12. #292
    Join Date
    May 2009
    Posts
    40
    My new work
    [ame="http://www.youtube.com/watch?v=y2Z6Rv6BEHM"]Пайка резца - YouTube[/ame]
    [ame="http://www.youtube.com/watch?v=2oMPvaB6LkE"]Индукционный нагрев. Закалка ТВЧ. - YouTube[/ame]
    [ame="http://www.youtube.com/watch?v=crnmado3zyA"]Плавка меди 15 кВт - YouTube[/ame]
    [ame="http://www.youtube.com/watch?v=r7gFWdAfCHo"]Плавка 2 часть 1.wmv - YouTube[/ame]
    [ame="http://www.youtube.com/watch?v=0yZmpFjsgDA"]Плавка 2 часть 2.wmv - YouTube[/ame]
    [ame="http://www.youtube.com/watch?v=D7Z5yPmgsUM"]Плавка 2 часть 3.wmv - YouTube[/ame]
    [ame="http://www.youtube.com/watch?v=Qlmpx5zB7ws"]НАЛАДКА 1а.wmv - YouTube[/ame]
    [ame="http://www.youtube.com/watch?v=Qlmpx5zB7ws"]НАЛАДКА 1а.wmv - YouTube[/ame]
    Attached Thumbnails Attached Thumbnails ????.jpg   ????0258.jpg  

  13. #293
    Join Date
    Dec 2010
    Posts
    153
    Anyone happen to know how to size a work coil?

    I am working on building a 10kW Induction heater to primarily melt aluminum and sometimes what ever else I have on hand. Cast iron would be nice but I know that will be a stretch for it.

    Anyway looking at a 16lb batch size using a 7" max OD x 8.5" tall crucible so that puts the ID of my coil at 7.5" to 8" but the real question is how many turns should I aim for? Once I know how many turns to aim for I can set up the rest of the tank circuit.

    For a inverter I am using a full bridge IGBT output stage coupled into a Ferrite 20 to 1 transformer. Max input voltage will be 240Vac with 50A of available current (single phase full wave rectified so ~340V peek) at ~65kHz switching rate. Long term will have a input buck converter to control DC voltage but will just start with a Variac I have sitting around. The tank circuit is currently set up for series LC. Full setup (including IGBTs and tank cap) will be water cooled.

    So is there any formulas that will let you calculate the correct # of turns to get the maxim amount of power into a 8" diameter pot of metal?

    Thanks.

  14. #294
    Join Date
    Apr 2009
    Posts
    7
    Hi Wireb, the coil turns will depend on workpiece height( pot's height), cooper tubing diameter used,desired frecuency( inductance related with coil geometrical parameters),you can use less turns with more current or more turns with less currrent to obtain the same result. is not easy to calcullate the optimal number of turns is a compromise between above parameters.


    regards,
    Hernan

  15. #295
    Join Date
    Dec 2010
    Posts
    153
    Thanks for the reply.

    Is there any general formulas that will get me close to the inductance of a coil based on tubing diameter, # of turns, and diameter and any other physical dimensions?

    I know this will not be exact but would like to try and get a rough idea what size coil I should shoot for.

    Few more details I just got a pair of 3.75uF snubber caps for the tank (conduction cooled). So that gives me choices of 1.875, 3.75, 7.5uF (7.5uF will have the highest current handling and 1.875 will have the lowest)

  16. #296
    Join Date
    Apr 2009
    Posts
    7
    Wireb, the formula used in some literature: L coil(uHy)= (r² X N²)/(9r +10h)

    where: L coil's inductance
    r: is the radius of de coil
    N: number of turns
    h: height of the coil

    Hernan

  17. #297
    Join Date
    May 2009
    Posts
    40
    melting steel 25 kg
    power of 25 kW
    Attached Thumbnails Attached Thumbnails ????0438.jpg   ????0439.jpg   ????0440.jpg   ????0441.jpg  

    ????0442.jpg   ????0443.jpg   ????0444.jpg   ????0445.jpg  

    ????0446.jpg   ????0447.jpg   ????0448.jpg  

  18. #298
    Join Date
    Nov 2012
    Posts
    0

    Smile Failed attempt - Induction heating

    Hi

    I tried heating the pipe (P91) using the coils of my induction cooker. Took out the coils and wrapped it around the pipe with the ceramic buds.
    Pipe thickness = 3.8mm

    The moments I switched on the cooker, it showed circuit malfunction!

    Any idea why that happened? Would appreciate your help.

    Best Regards,
    Gyan

  19. #299
    Join Date
    May 2009
    Posts
    40

    Re: Induction furnace

    My new induction furnace
    2.8 kW
    200 * 200 * 400 mm
    V = 120 cc

    Click image for larger version. 

Name:	P5231314.jpg 
Views:	0 
Size:	54.6 KB 
ID:	281314Click image for larger version. 

Name:	P5231316.jpg 
Views:	0 
Size:	43.0 KB 
ID:	281316Click image for larger version. 

Name:	P5231317.jpg 
Views:	0 
Size:	45.2 KB 
ID:	281318

  20. #300

    Re: Induction furnace

    Steel Crackers has completed installation of an induction furnace in dist. Hooghly, West Bengal

    Steel Crackers has completed installation of a 1×4 tonne induction furnace at Village Dhobapukur, dist. Hooghly, West Bengal on 5.615 acres of existing land. The estimated cost of the project is Rs. 15 million. The project has came up in the existing plant comprising of a 2×5 tonne furnace producing 42,000 TPA of billet/ingot & 2000 TPA re-rolled bars. Work on the project was completed in 2015. The project is waiting for Consent To Operate order from the Government. The project is scheduled for commissioning after the receipt of Consent To Operate.

    Source : https://www.domexinfo.in/blog/induct...-installation/

Page 15 of 16 513141516

Similar Threads

  1. 12.5 kW Induction Furnace
    By meanu in forum Casting Metals
    Replies: 1
    Last Post: 04-24-2013, 07:19 AM
  2. My Furnace
    By vertek in forum Casting Metals
    Replies: 6
    Last Post: 02-28-2008, 07:15 AM
  3. induction furnace
    By vallabesan in forum CNC Machine Related Electronics
    Replies: 5
    Last Post: 12-13-2007, 04:19 AM
  4. Arc Furnace
    By aggie_67 in forum Casting Metals
    Replies: 4
    Last Post: 08-28-2007, 06:27 AM
  5. DIY Oil Furnace
    By aggie_67 in forum Casting Metals
    Replies: 9
    Last Post: 09-24-2006, 02:35 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •