Need help calculating magnetic coil power specs

Discussion in 'General Electronics Chat' started by ElectromagnetNewbee, Jul 13, 2014.

  1. ElectromagnetNewbee

    Thread Starter Member

    Jul 13, 2014
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    I am planning on rolling an electromagnetic coil using Magnet Wire, Enameled Copper Wire, 14 AWG, 10 pounds, 0.0655" Diameter, Red. - This will just be one large round coil basically. I need a transformer to power this with maximum amps/power/voltage that a 10 pound coil with these specs will support without overheating.

    I eventually need/want a VFD (Variable Frequency Drive) to power this coil, but a Transformer with 40 hertz OUTPUT will work for now (whatever is cheaper as I'm short on cash).

    Would someone provide me with the specs and equipment with links so I can purchase what i need for this? Im a software developer, not an electrical guy so I'm new to all of this. thank you for your help!

    Nate
     
  2. inwo

    Well-Known Member

    Nov 7, 2013
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    Where are you located that you have 40hz?
    " but a Transformer with 40 hertz OUTPUT will work for now "

    It may be hard to find a vfd for single phase.

    What is the application? You may get more help if you allow a little flexibility on design.
     
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  3. ElectromagnetNewbee

    Thread Starter Member

    Jul 13, 2014
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    im in the New York City area so input is standard 60 hertz. but i need to bring the 'output' hertz via the coil to generate a 40 hertz wave, so i need a conversion to take place via some device like a transformer or VFD.

    I found some specs online that said 12 AWG will support 41 open air amps? does this sound correct? how many volts would a 10 pound coil require to power this?
     
  4. ElectromagnetNewbee

    Thread Starter Member

    Jul 13, 2014
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    also, once i wrap this large 10 pound coil... what do i coat the coil with so it stays together and does not unravel when i take it out of its rolling container?

    can i coat the coil in some acrylic paint so it hardens and won't unravel? what would i use for some thing like that?
     
  5. alfacliff

    Well-Known Member

    Dec 13, 2013
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    open air amps and amps when wound into a multilayer coil are different. a multi layer coil holds the heat in and cant handle as much current as open air wire. you should probably figure on 20 or so amps max.
     
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  6. ElectromagnetNewbee

    Thread Starter Member

    Jul 13, 2014
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    Thank you for the explanation alfacliff! its very important for me to get these things figured out so i can accomplish this project. much appreciated to both of you, InWo, thank you as well :)
     
  7. Papabravo

    Expert

    Feb 24, 2006
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    Why do you need 40 Hz, and what is the purpose of this coil? I for one want to know what you intend this thing to do because I think you have expectations that will be difficult to meet.
     
  8. ElectromagnetNewbee

    Thread Starter Member

    Jul 13, 2014
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    i am doing experiments on the effect of different frequency waves on living tissue. that is why I'm needing a VFD and lower hertz than is commonly used. the end result is the wave frequency produced by the coil.

    What can I use on the coil to coat it so it does not fall apart after rolling it? is there something that holds it together cause i don't want to tie it. I'm thinking of using some acrylic bases clear coat? can you guys please point me in the right direction for this?
     
  9. Papabravo

    Expert

    Feb 24, 2006
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    I'm interested in knowing what kind of "living tissue" you might be referring to and what kind of results you expect to discover or confirm. Even though some kinds of experiments can be performed, it does not mean that they should be performed. In particular I'm not sure the output of a typical VFD is what you want or need.
     
  10. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    A "transformer" doesn't transform frequency; only voltage and current. The output from a transformer with 60Hz connected to its primary is at 60Hz.

    A VFD is an expensive electronic frequency converter usually used to speed-control an AC induction motor. Such a motor connected directly to 60Hz would turn at an rpm closely related to the line frequency. These things are usually rated at hundreds of V and many kW.

    Methinks you need a simple audio signal generator, with possibly an (audio) isolation transformer between the sig gen and the sample...
     
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  11. ElectromagnetNewbee

    Thread Starter Member

    Jul 13, 2014
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    Here is a link from amazon of a VFD I am looking at: http://www.amazon.com/Sanven-Freque..._sbs_hi_2?ie=UTF8&refRID=0BG6TQGYFVDDH7XM31VH

    the main thing to look at on this page is the Outpute Frequency: 0 to 400 Hz as shown.

    My goal is to have an output frequency from the electromagnetic coil that can operate at my choosen, variable setting. In other words.. this changes the actual wave of the magnetism correct??? or am i incorrect on this?
     
  12. Sensacell

    Well-Known Member

    Jun 19, 2012
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    When you say "different frequency waves" you mean a time varying magnetic field? How did you arrive at your coil design?

    For 40 Hz, you may be able to produce much stronger magnetic fields using more turns of thinner wire- at a lower current value, resulting in simpler and cheaper electronics.
     
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  13. inwo

    Well-Known Member

    Nov 7, 2013
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    There was just a thread about a cheap sine wave inverter. Where the link showed changing the frequency a bit.

    I wonder if an inverter hack would be an option.

    I believe it will be hard to get a standard vfd to output single phase. As single phase protection is built in.
     
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  14. MaxHeadRoom

    Expert

    Jul 18, 2013
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    That is one of the Chinese Huanyang VFD's, not that high a quality item!
    Also a VFD does not output a 'clean' sine wave, it has a high frequency PWM content.
    It also may not take kindly to only using 2 phases for 1 phase, if it does work, then a series choke would be advised to take the high frequency content out, as is the common practice when using a 3ph motor.
    Max.
     
  15. wayneh

    Expert

    Sep 9, 2010
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    For an electric field, you don't need a coil, just plates at different voltages. You can generate a magnetic field with a coil, but to do any meaningful experiment you need to define the volume of the "treatment area", the field strengths you hope to achieve in that volume, and the frequency range you want to cover. In other words we need specifications.

    You should realize that coil geometry, the presence and properties of a core, and other factors will affect the field strength and the shape of the field lines. For instance a gapped toroid can produce an intense, defined field very efficiently.

    I assume your goal is not to just pulse current through a wire, but to get the biggest magnetic "bang" for your buck?
     
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  16. Papabravo

    Expert

    Feb 24, 2006
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    It is also the case that a VFD usually does not output a sine wave, but a modified stair step approximation. Were you aware of this?
     
  17. ElectromagnetNewbee

    Thread Starter Member

    Jul 13, 2014
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    Yes, I'm talking about a time varying magnetic field I believe, or as i understand it, the output frequency, hertz! where the wavelengths are different because of the frequency change, (example 0 to 400 hertz). another example is its kinda like the energy wavelengths from the Sun or the waves/magnetic field produced from a strong neodymium magnet.
     
  18. ElectromagnetNewbee

    Thread Starter Member

    Jul 13, 2014
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    Correct! this is a constant magnetic wave on the tissue for an extended amount of time.

    The thing i need is the make sure the VFD and my rolled coil will output the different wavelengths through the copper coil... hence the 0 to 400 hertz range which will make the magnetic field generated operate at different wavelength, like faster/slower waves per second kinda thing. isn't that what the frequency range changing does?

    does this logic sound correct? i think it is. and can it be done with the VFD link from amazon.com that i posted? i think it can be? or am I wrong?
     
  19. ElectromagnetNewbee

    Thread Starter Member

    Jul 13, 2014
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    Just to confirm, no, I'm not doing anything with audio signaling. this is the equivelent of putting a large neodymium magnet on tissue, the frequency output from a neodymium magnet operates at an earth frequency. this is an example of what I'm talking about. :)
     
  20. ElectromagnetNewbee

    Thread Starter Member

    Jul 13, 2014
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    To better communicate what I'm trying to experiment with please watch this short 5 min youtube video: https://www.youtube.com/watch?v=dLMG1flT-zs&list=PL7LVi7WA7MkfJisbPhvLdyQmxmoFqlEQU

    the concept in this video is what you need to take away for things I'm trying to do. Cell phones, TVs, Computer monitors AM radio, FM radio all produce harmful electromagnetic frequencies to the body. I'm researching frequencies that may be helpful to the body (like strong neodymium magnets but in electric coil form). this is why i am experimenting and collecting data on this. trying to find a healing frequency my friends :)
     
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