Is It Possible to Fry A Transformer

Discussion in 'General Electronics Chat' started by sirnobody, Feb 15, 2011.

  1. sirnobody

    Thread Starter New Member

    Feb 15, 2011
    3
    0
    Hey everybody,
    I've been working on a side project of making biodiesel and I have hit a wall regarding making a heating element for it. Basically, i need to heat about a gallon of cooking oil to ~150 degrees farenheit and i've been trying to figure out how to make a heating element for it and it doesn't make any sense. Do you get more heat from a circuit if you have high or low resistance?

    Going back to the topic of the thread, I bought a transformer for bell chimes, 8 volts 10 VA (is VA the same as Watts?) and i hooked it up to an extension cord and plugged it into an outlet and ran a guitar string across it because i read that you can use guitar strings to heat up and cut stuff (such as foam). It got pretty hot but i figured it could use more power so i hooked it up to the 24V 20VA screw on the transformer instead and connected it. Nothing happened. I got my multimeter out and checked and the primary circuit of the transformer was somehow no longer working. I got a new one now but i can't figure out what I did wrong. I didn't even know it was possible to break the primary coil of a transformer when it was plugged in to a proper power source.

    Any suggestions or tips on how to make a heating element and how not to break my new transformer would be appreciated. I really don't know much about electronics so any input would be appreciated.

    Thanks,
    Sirnobody
     
  2. Low Voltage

    New Member

    May 21, 2008
    8
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    Any place that sells stuff for horses has a heating ring you can through into a bucket of liquid and plug into 115 wall socket. The seller will know if 150° can be had from the ring.
     
  3. mbohuntr

    Active Member

    Apr 6, 2009
    413
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    Plugging stuff into a wall socket to see what happens is a sure way to either hurt yourself very badly, or burn the house down. I would suggest reading up on Ohms law, Transformer theory, and perhaps some physics sites. Have someone here point you to viable circuits and ask plenty of questions BEFORE plugging something in....:eek:
     
  4. nsaspook

    AAC Fanatic!

    Aug 27, 2009
    2,908
    2,168
    Inside the windings of most small cheap bell transformers is a winding overload wire (fuse) that will open in case of a prolonged over-current. (like shorting a wire on the secondary.) In better units there usually is a PTC that will reset when the overload is removed.
    http://en.wikipedia.org/wiki/Resettable_fuse

    The proper thing to do is to use an approved heating plate.
     
  5. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    That or look up Watlow Firerod Heating elements.
     
  6. PackratKing

    Well-Known Member

    Jul 13, 2008
    850
    215
    Another possibility is the heat element from an electric residential hotwater heater.....aka a "Calrod " which can be had in a whole array of different sizes, configs, voltages and wattages from your local HVAC supplier.

    In the event any of the following sounds overly complicated or daunting, please retain the service of a qualified electrician to set this up for you.

    Calrods can be wired direct to 120v AC without need of a transformer, although I would include an appropriate limit switch, -- google "Klixon" -- on the tank your biodiesel is cooking in...... as well as an on/off toggle, and a fuse. Make certain all your connections are clean, tight, and well insulated prior to throwing the switch. :DAlso be sure it is never turned on between batches, as in not immersed, it will certainly get hot enough to ignite your oil !!
     
    Last edited: Feb 16, 2011
  7. Jaguarjoe

    Active Member

    Apr 7, 2010
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  8. sirnobody

    Thread Starter New Member

    Feb 15, 2011
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    0
    The problem with using a conventional heater is that it is meant to be immersed in whatever liquid it is heating. My system involves pumping the oil through a tube from the bottom of the tank and then dumping it out of the top to stir it. I was thinking of putting a brass fitting through a section of the tube then using a heating element to heat that up and transferring the heat to the oil as it passes through the brass fitting (hopefully and assuming its properly insulated) creating a more streamlined and heat efficient system for heating my oil. So I would need to be able to wrap the heating element around the brass fitting rather than immerse it in the oil.
     
  9. mbohuntr

    Active Member

    Apr 6, 2009
    413
    32
    Hot tub heaters might be close to that.
     
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