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Thread: Modifying a generator output

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    Default Modifying a generator output

    Yes I know i purchasing a pure sine wave genny would be easier.
    I thought I did, they wont accept an exchange and the ACCC couldn't help either. SOOOOO
    My issue:

    Generator causes LED downlights to pulse, therefore testing came down to a modified sinewave output.

    My question is. Can I play and get this to become Pure Sine wave?
    If so how?



Look Here ->
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    What genny brand/model is it?

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    Its a chinese one I'm guessing..Iketa


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    Ok, I see why ACCC went cold on it (unless reseller updated stuff) - that model marked as not being sine wave. That means it's probably an inverter genset (AC from alternator rectified and bulked into DC, and then inverter chops it up into AC again).

    I don't think there's anything you can do ; you'd really need to replace the inverter board on the genset for one designed to do sine wave (or a closer approximation to sine than what you've got) ; there are 240VAC power conditioners out there, but they're hellishly expensive.

    I take it the lights work fine on mains 240VAC?

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    Yeah right.... DOH!!!

    Lights have no issue on "MAINS" what so ever.

    The funny thing is I have no issue on my 4KVA chinese thing either..
    Only changed for more power ability

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    The 4KVA might not be inverter genset, but rather a synchronous alternator (which are almost always pure sine output)

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    Have you tried higher loads other than the LED lights?
    Also do they still pulse when you have other loads on at the same time?

    It might need a minimum load to run stabile by (bad)design, or it is just faulty.

    LED down lights shouldn't care about sine wave, trapeze wave or even square wave.
    Last edited by Uncle Fester; 24-08-21 at 06:53 PM.
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    You can through anything at these LEDs. The genny is playing up, not the LEDs.

    Here for shits and giggles I just connected a run of the mill Bunnings 10W downlight LED to DC !
    108V was all I could get out of my lab supply but it glows bright and stabile:

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    The genny could be working correctly ~ a hell of a lot depends on A. which LED driver is used (if any), and B. just how noisy/ugly the inverted AC supply is.

    For instance, the AC waveform from many of these cheap inverter gensets can look this horrid ;



    A lot of LED driver chips can't cope with that sort of waveform (in particular the ringing just after mosfet switching for obvious reasons) ; never used to be too much of a bother until they started using chips with the rectifier builtin

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    Thanks all for the input people, @unclefester those are the downlights I am running here by the looks. Arlec tri color.

    This Vimeo link is what the lights are doing on genny.
    "Reportedly" on the screen of the genny 233v 50hz... I am waiting for my Oscilloscope to arrive to do my own testing.


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    A silly question. Do you use a dimmer on them?

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    Yeah I do....
    But it happens in rooms without dimmer so I just figured it wasnt related.
    (Just as a side note) I have both mechanical and electronic dimmers and it happens on both..

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    Quote Originally Posted by bongo View Post
    Thanks all for the input people, @unclefester those are the downlights I am running here by the looks. Arlec tri color.

    This Vimeo link is what the lights are doing on genny.
    "Reportedly" on the screen of the genny 233v 50hz... I am waiting for my Oscilloscope to arrive to do my own testing.

    Video link got clobbered by tags, so here -->

    That's not the sort of flicker I was referencing, and that does indeed look like the genset is behaving weird

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    Quote Originally Posted by bongo View Post
    Thanks all for the input people, @unclefester those are the downlights I am running here by the looks. Arlec tri color.

    This Vimeo link is what the lights are doing on genny.
    "Reportedly" on the screen of the genny 233v 50hz... I am waiting for my Oscilloscope to arrive to do my own testing.


    Probably Arlec or Deta. I don't have the box but they do have the 3 colour temp setting and am sure they all work the same.

    So did you try running something together with the lights? Maybe switch on a toaster and see if they still flicker. Keep in mind that in a domestic household, power points are not on the same circuit as the lights.
    How does a microwave perform?

    Do not try yet on a fridge. That intermittent power supply could stuff up your fridge compressor.
    Last edited by Uncle Fester; 25-08-21 at 12:12 PM.
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    Our dining light had an Osram RGBW smart LED bulb in it, but a few days ago I swapped it out for a 'Brilliant' brand smart RGB because I got an email from Osram saying they are shutting down support for it at the end of this month.
    The new 'Brilliant' bulb had a flicker. Not much of a flicker but enough to be annoying.
    The dining light always run through a dimmer from when it was incandescent, which with the LED bulbs we just left the dimmer full blast all the time.
    I took the dimmer out of circuit and now the 'Brilliant' is brilliant.
    Last edited by loopyloo; 25-08-21 at 01:24 PM.

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    Do you have your lights specification? The most important question is what power factor are they?
    Majority of LED lights have leading power factor and your generator should be able to output negative KVARs to maintain stable voltage when the load is biased towards negative power factor. Not many cheap generators can do it which results in voltage and frequency bouncing up and down so this might be the problem you see.
    The quickest test would be to correct power factor by connecting inductive load of sufficient size to move load to lagging power factor area.

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    Quote Originally Posted by fromaron View Post
    Do you have your lights specification? The most important question is what power factor are they?
    After I looked at the link you provided it is not clear if it's a standard AVR generator or sine wave inverter used.
    If it is the later have a look at the link for a good explanation and hopefully good tip on how to fight harmonics introduced by non-linear modes.

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