Watch out for what an inverter can do

Discussion in 'Motorhome Chat' started by rosalan, Dec 21, 2015.

  1. rosalan

    rosalan Funster

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    In Spain this summer, we bought an 800w inverter, not the most expensive pure sine wave type (whatever they are) to charge the batteries on our electric bikes; perfect!
    As there was plenty of power available, I could not resist charging my little electric toothbrush. Big mistake! Apparently the shape of the sine wave does matter, well it did to my toothbrush, it destroyed it. ( later I read in the small print that this could happen)
    Alan
     
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  2. pappajohn

    pappajohn Funster Life Member

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    I cant understand that.

    Genuine pure sinewave is as close as it gets to mains leccy....and you use that at home without problems.
     
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  3. JockandRita

    JockandRita Funster Life Member

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    John, Alan is saying that it wasn't the most expensive pure sine wave type.
    When I charge my Braun electric shaver via a modified sine wave inverter, the charge never lasts as long as a mains charge, but other than that, it seems to work okay.


    Cheers,

    Jock. :)
     
  4. JeanLuc

    JeanLuc Funster

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    Modified or Quasi-sine wave inverters: i.e. not pure sine wave models, can cause havoc with inductive motors and devices. As you have found out, electric toothbrushes are charged by inductive coupling and don't like square waves. This also applies to other devices that have 'contactless' charging. I have also read that quasi-sine wave inverters can destroy expensive hair tongs (e.g. GHD).
     
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  5. pappajohn

    pappajohn Funster Life Member

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    My mistake, i misread that thinking most expensive.
     
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  6. Derbyshire wanderer

    Derbyshire wanderer Funster Life Member

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    I suspect that the inverter is NOT as described. Pure sine wave is exactly the same as mains power. Cooking the toothbrush can only point to it being modified not pure.
     
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  7. JockandRita

    JockandRita Funster Life Member

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    Wot he posted..............
    Jock. :)
     
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  8. Derbyshire wanderer

    Derbyshire wanderer Funster Life Member

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    Ah yes I see now (red wine must have muddied the thought from vision process).
    I thought it meant a cheaper pure sine wave. Doh
     
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  9. DavidG58

    DavidG58 Funster

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    So did I, Jock must be on Alans wave length

    (did you see what I did there) :):)
     
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  10. JockandRita

    JockandRita Funster Life Member

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    Not when you did it David, as I was dead to the world by that time. ;)
    Which is obviously pure. :xrofl:

    Cheers,

    Jock.:xsmile:
     
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  11. jenny and mitch

    jenny and mitch Funster

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    It must be a sine ??
     
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  12. Bill_OR

    Bill_OR Funster

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    Careful - I think you're going off at a tangent!
     
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  13. jenny and mitch

    jenny and mitch Funster

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    Watt ??
     
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  14. hilldweller

    hilldweller Funster Life Member

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    Anything very small is in danger from the rough treatment handed out by big cheap inverters. Their tiny capacitors and suppressors can't absorb the spikes created by the crude waveform.

    300W pure sine way here.
     
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  15. TUCANO

    TUCANO Funster

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    This is all electrifying to me :xeek:
     
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  16. jockaneezer

    jockaneezer Funster

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    We used to have a teacher we called Sine Wave, he had one leg a bit shorter than the other and couldn't draw a straight line across the blackboard.
     
  17. PhilandMena

    PhilandMena Funster

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    Me too, all for my Toothbrush.
     
  18. jenny and mitch

    jenny and mitch Funster

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    Did he have a "limp" handshake ?
     
  19. Rapido925M

    Rapido925M Funster

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    Do you remember those experiments at school where you (or teacher :sleep:) moved a magnet in a coil of wire, magically producing electricity? (It went under the heading of "electro-magnetic induction" - work it out!)

    The faster you changed the magnetic field, the bigger the voltage produced.

    This lesson will probably have led to a discussion of the transformer, where a changing voltage (in the primary coil) creates a changing magnetic field which creates a changing voltage (in the secondary coil).

    The inverter provides electrical power to the "charging base": it produces a changing magnetic field which links to the device: a coil inside the device produces the electricity to charge (or fry) the internal battery.

    When sinusoidal changing fields are applied, you get sinusoidal voltage changes. However, if you use a wave which suddenly change the field (eg triangular-shaped, or even worse, square shaped) then you get a sudden, large change in voltage (in the secondary).

    This is what fries your toothbrush/hair-tongs or, as stated earlier, any "charged by induction" device.

    SIMPLES :whistle: - Gordon
     
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  20. PeteH

    PeteH Funster

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    So if you have 2 working in tandem? Is that a Cosine?. I guess that`s all angles covered then?

    Pete
     
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