28 guage magnet wire.

Discussion in 'General Electronics Chat' started by zayed, Feb 14, 2009.

  1. zayed

    Thread Starter New Member

    Feb 14, 2009
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    :D now that i have registerd, is 28 guage magnent wire rated for 120V?
     
  2. bertus

    Administrator

    Apr 5, 2008
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  3. leftyretro

    Active Member

    Nov 25, 2008
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    Voltage rating for wire is dependent on the insulation material and thickness, not the gauge size. You will have to research wire manufactures specifications for the insulation used in your wire.

    Lefty
     
  4. Wendy

    Moderator

    Mar 24, 2008
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    Glad to see ya on board. You missed the discription on this forum though...

    The other forums tend to be more fun though. One thought about your question, most AC motors and power transformers use enameled wire (or a pretty close equivalent), so something exists out there. I wouldn't make the assumption though, unless you get the wire from such a source.
     
  5. beenthere

    Retired Moderator

    Apr 20, 2004
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    You would need to look at the manufacturer's specs on the wire. That enamel film is very thin.
     
  6. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    Did a moderator move this thread?
     
  7. Wendy

    Moderator

    Mar 24, 2008
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    Yep........
     
  8. Andrew Leigh

    Well-Known Member

    Sep 8, 2008
    92
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    Hi,

    Most magnet wire coatings can take extremely high a.c. voltages in the short term.

    Typically the wire used in relays and small transformers tends to be on the smaller end of the size range and break readily when mechanically stripping the coating off prior to soldering. The range is generally up to 0.25mm but can be thicker, the covering is usually a "self fluxing" Polyurethane coating which allows one to solder through the coating. These are normaly sold as GR1 or GR2, GR2 has more coats and therefore is electrically stronger but fill factor drops (turns /cm2).

    Wire up to 0.25 tends to be pad coated whilst wire over that will be die coated. Die coating is more uniform, repeatable and offers better results.

    Wire intended for oilfilled transformers and electric motors tends to be a Polyesterimide covering with a amide imide overcoat (the Chinese and others don't always overcoat). Typically these are intended for operation up to 200°C. Most are GR2 and some GR3.

    Finally, it depends on how long you want it to be at 120V? On the latter covering a 60 second 50Hz a.c test conducted on a twisted pair of wires will seldom fail at less that 10kV. BUT, the conductor would not be able to take that voltage continuosly and WILL fail prematurely. In oilfilled transformer design most designs allow for a couple of volts per turn, this is often more a function of the ratios needed. In the case of many turns on a H.V. secondary winding the problem is one of interlayer voltage and flashovers layer to layer.

    In electric motors the volts per turn tend to be higher.

    It must be mentioned that most magnet wire fails mechnically first and then electrically. To the untrained eyed the damage of the electrical failure obfuscates the mechanical cause.

    Whats the application?
    For how long will it maintain that voltage?
    a.c. (more damaging) or d.c.?
    How clean / dirty is the supply (magnet wire is not a lover of modified sine waves)?
    What temperature?

    Cheers
    Andrew
     
    Last edited: Feb 15, 2009
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