12.5 kW Induction Furnace

Discussion in 'The Projects Forum' started by meanu, Jan 19, 2013.

  1. meanu

    Thread Starter New Member

    Jan 23, 2012
    6
    0
    12.5 kW Induction Furnace
    Hello Members

    I want to build a 12.5kW Induction Furnace. I am designing it for 30 kW, but am only going to run it at 12.5 kW.

    I have many high voltage, current components for the frontend [diodes & phase control thyristors in the main]

    The tank circuit for the back end shouldn't be too much of a problem.

    However, the control section [centre] I need some help.

    Has any one built a Furnace like this?

    Help or advice Please?

    Kind regards

    meanu​
     
  2. jt6245

    Member

    Feb 18, 2011
    21
    3
    I don't know induction furnace.Just want to know how do you get 52A (12500/240) current from ac main ?
     
  3. kubeek

    AAC Fanatic!

    Sep 20, 2005
    4,670
    804
    Well obviously industrial-size heaters need industrial-sized mains breaker.

    meanu: you should google induction furnace schematic or induction heater or something similar, that brings me a lot of sites that discuss the design process, for example at danyk.wz.cz is a pretty good collection of different makes.

    Also, what part of the control circuit do you have problem with? Do you need to control the furnace as in maintaining set temperature or power, or do you have trouble with controlling the IGBTs?
     
    meanu likes this.
  4. meanu

    Thread Starter New Member

    Jan 23, 2012
    6
    0
    Hello jt6245

    I have 415V 3 Phase Supply with 16 sq.mm Mains incoming. My House has a 100A 3 Phase Mains Switch and my Shed a 63 A mains Switch.

    On my calculations, at 30 kW design, Iwill be drawing 25 A per Phase.

    Correct me if I am incorrect.

    So if I limit the output to 15kW max. I will be only drawing 12.5 A per phase.

    Kind Regards

    meanu
     
  5. evilclem

    Member

    Dec 20, 2011
    118
    16
    Hi Meanu,

    If you wish to use 3 phases then you will need 3 coils for your induction heater. 12.5 A per phase is 3 kW per phase and 9 kW total.
     
  6. evilclem

    Member

    Dec 20, 2011
    118
    16
    Also: http://www.practicalcontrol.com.au/
    These chaps seem to have some nice reasonably priced 3 phase SSR's.

    They look to have some adequate process controllers as well.
     
  7. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    6,357
    718
    Searching for "Induction Forge Schematic", I Found This, which uses an Arduino and some logic for tank frequency control.


    Searching for "induction forge" will point you to quite a lot of information. This topic is on the line for allowed discussion, due to safety issues from the voltages and power involved.
     
  8. meanu

    Thread Starter New Member

    Jan 23, 2012
    6
    0
    Hello

    A reply to Senior Members "evilclem" & "thatoneguy".

    Thankyou for your comments and advice.

    If the Power Inverter runs Phase to Neutral, then the input voltage will be 240V, however, if I am just running Phase then it will be 415V. Is this correct ?

    The Inverter will have an Output of DC which will then be filtered and chopped to the frequency required.

    The Power will be controlled by phase control of the Thyristors.

    These are only early days.

    I have more than enough High Voltage, High Current SCRs, Diodes and IGBTs.

    Most of them are rated at at least 1200V 1000A, so I think they will just be big enough.

    Why am I going to use such large capacity components, you ask ?

    For the best reason of all. They are FREE.

    Thankyou both for your interest and willingness to help.

    Kind Regards

    meanu

    Just one other thing, the Furnace that I am basing this on only has one [1] Furnace Coil, which is Water Cooled, and packed with refractory material.

    The crucible can be pushed up from the furnace, when the melt is at correct temperature by a hydraulic Cylinder which is manually operated.
     
  9. meanu

    Thread Starter New Member

    Jan 23, 2012
    6
    0
    Hello kubeek

    I read your post again and looked up the site that you recommended.

    There is definitely some good information there, however, I Can't speak POLISH.


    Thankyou for taking the time to reply.

    Kind Regards

    meanu
     
  10. kubeek

    AAC Fanatic!

    Sep 20, 2005
    4,670
    804
    It may look a bit similar, but it is not Polish but Czech. Anyway, the site has an english version (see the flag in the upper right corner?) and if you need I can check the details in the original if some parts of the english translation seem ambiguous (his english is not very good).
     
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