12V Induction Heater for air heating

Discussion in 'General Electronics Chat' started by dhan_louie, Aug 10, 2011.

  1. dhan_louie

    Thread Starter New Member

    Aug 10, 2011
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    Hello everyone, I was wondering if I could use about 12V, 500mA-1A AC power supply (square wave) to create an induction heater. The target temperature is about 50-100°C. I was trying to make a dryer chamber from which this heater could then be used. If so, then what should be the optimum frequency for that and how could I control the temperature? Thanks in advanced. :)
     
  2. #12

    Expert

    Nov 30, 2010
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    You haven't given enough information. Exactly what is it that you want to heat to 50C-100C? Air? Air doesn't respond to induction heating.

    If I assume a lot, I'd say that 6 to 12 watts won't heat very much stuff. I find it odd that you would want to use megacycles per second to heat something when electricity turns into heat very easily. Something as simple as a light bulb might be all you need.

    Controlling the temperature requires a thermostat of some kind, and there are many kinds. The accuracy required is usually the guiding principle.
     
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  3. dhan_louie

    Thread Starter New Member

    Aug 10, 2011
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    First of all, thank you for your reply.

    I just wanted to heat a thin metal sheet where air will flow through. So that air would heat up indirectly. Also, I can't use light bulbs since I could be drying up stuff which are light sensitive during development (i.e. photographs). That's why I will put it in an enclosure where light could not enter. Also, for the air to flow, I am currently using a fan. Currently I have a flat spiral coil inductor which I calculated to have an inductance of approximately 98.507uH.
     
  4. #12

    Expert

    Nov 30, 2010
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    12 watts will heat about .27 cfm from 25C to 100C.

    Electric furnaces for residences use a resistor in the air flow to heat the air, and it works very well, and that's how I would do this. How you do it is entirely your choice. I just have to step aside because I know nothing about induction heating.
     
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  5. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    "12 watts will heat about .27 cfm from 25C to 100C."

    That sounds high? 12 watts for a dryer chamber seems way too underpowered to me, unless the dryer chamber is very small.

    No need for induction heating. Bolt some transistors to the metal sheet and put some current through the transistors.

    Because they are transistors you get the benefit of only needing a very small current to control them so you can control direct from a micro or opamp (or a pot!) etc.
     
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  6. dhan_louie

    Thread Starter New Member

    Aug 10, 2011
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    12 watts is enough since the drying chamber is quite small. I will be putting only small items in it :D. When using transistors, how much heat would be generated given the said power supply?
     
  7. #12

    Expert

    Nov 30, 2010
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    40.956 B.T.U.s
     
  8. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    SOOO many details are missing...
    How fast must your chamber get to temperature?
    What materials are used on the chamber walls. Is it insulated/non-insulated,etc....ie how much heat is lost through the walls of said small chamber.

    Also how can we answer such a generic question about the "when using transistors..blah blah blah" when we have NO idea what they are doing/how many you have,etc... ?? All transistors are not just a transistor..

    Is this for a pot vaporizer? I suspect so..
     
  9. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    Given the "said power supply" of 12v 1A max you would get 12W max heat "generated".

    12W will heat a football-sized cabinet to around 50'C provided it has styrofoam walls to try to minimise heat losses.

    Of course if it is a "dryer" where you must have airflow through the cabinet that is a massive heat loss, so you will get a much lower temperature.
     
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