Modified Sinewave

Discussion in 'Power cuts' started by mickey69, 17 Jun 2009.

  1. mickey69

    mickey69

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    I was always under the impression that u cant use these for sensitive devices buttt....

    Modified sine power inverter​
    Modified sine wave power inverters…or as we would refer to it, as general purpose inverters, are very cost effective. The “Modified” means the AC output waveform is not sinusoidal like your local energy supplier would supply to you, but the important part of the waveform is what is required for most electrical equipment. There is no certain indication or clear cut application where it is not suitable…but our field experience tells us, that in 90% of all applications, the modified sine wave power inverter is good for your application.
    This includes, but not limited to, things such as:
    • Cellular phone chargers
    • Laptops
    • Computers
    • Some fluorescent lights
    • Most DIY tools, like drills and jigsaws
    • Small fridges
    • Hairdryers and electric shavers.
    A lot of people refer to a “Quasi” wave or Square wave power inverter. These power inverters fall within the same category…”Quasi” is just a different name, but square wave... is usually the really “cheap and nasty “systems, which we prefer not to sell. A typical square wave inverter will have the output voltage varying as much as the battery voltage varies. This is not good for appliances. The better quality modified sine wave power inverters, will regulate the output AC voltage, even with a variable input battery voltage.
    [​IMG]
    One cycle of a sine wave, square wave, and modified square wave
    output
    It is important to realize and to understand that, an inverter...modified or true sine, is only as good as your battery banks’ ability to supply the energy required.
    Modified sine wave power inverters do tend the warm up motors (eg. fridges and fans) a bit more, but there are also better quality modified sine power inverters, which neutralize the third harmonic thereby eliminating these tendencies.
    There are complaints that modified sine wave power inverters cause some line interference on TVs ….this is more caused due to the high frequency content of the internals of the modified sine wave power inverter and not the wave form that goes out to your TV for power….In other words it is more a “poorly shielded” power inverter that causes the problem, then it is a waveform itself …a lot of these problems can be reduced simply by moving the inverter further away from the TV.
    [​IMG]
    Poorly shielded power inverters cause line interference on TVs

    Laptops and cellular phone chargers operate perfectly using a modified sine wave power inverter…Microwaves…well a true sine wave power inverter is better…refer to the report on various load tests which we done , for the comparative performances.
    What ever your application, please do not hesitate to contact us, to assist you with your application and make the correct choice of power inverter



    Nowu can get a 300w for about 450 bucks I think , should be ample for most people.....


    But after reading some of the threads on here I have been thinking and I know the brains are going to burn me on this but:


    Lets say you are running a 150 liter tank.... now a 100w heater should be sufficient for that size ( 2w's per gallon) + your pump say uses another 50w


    Now if the power cuts , that heater will only come on imtermittently when the thermostat requires and this of course will be influenced by the temp outside of the tank , but assuming an outside temp of lets say not less then 15 deg c and a tank temp of say 26... what formula can u use to determine your safe running time/approximate running time with a 105ah battery?


    Bring on the mathematicians here!
     
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  3. mickey69

    mickey69 Thread Starter

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    Do I need Modified Sine Wave, or Pure Sine Wave? Advantages of Pure Sine Wave inverters over modified sine wave inverters:
    a) Output voltage wave form is pure sine wave with very low harmonic distortion and clean power like utility-supplied electricity.
    b) Inductive loads like microwave ovens and motors run faster, quieter and cooler.
    c) Reduces audible and electrical noise in fans, fluorescent lights, audio amplifiers, TV, Game consoles, Fax, and answering machines.
    d) Prevents crashes in computers, weird print out, and glitches and noise in monitors.
    e) Reliably powers the following devices that will normally not work with modified sine wave inverters:
    • Laser printers, photocopiers, magneto-optical hard drives
    • Certain laptop computers (you should check with your manufacturer)
    • Some fluorescent lights with electronic ballasts
    • Power tools employing "solid state" power or variable speed control
    • Some battery chargers for cordless tools
    • Some new furnaces and pellet stoves with microprocessor control
    • Digital clocks with radios
    • Sewing machines with speed/microprocessor control
    • X-10 home automation system
    • Medical equipment such as oxygen concentrators
    We carry a full line of Pure Sine Wave Inverters here at DonRowe.com, though most of the inverters we carry are Modified Sine Wave inverters. Modified Sine Wave works well for most uses, and is the most common type of inverter on the market, as well as the most economical. Pure Sine Wave inverters (also called True Sine Wave) are more suited for sensitive electrical or electronic items such as laptop computers, stereos, laser printers, certain specialized applications such as medical equipment, a pellet stove with an internal computer, digital clocks, bread makers with multi-stage timers, and variable speed or rechargeable tools (see "Appliance Cautions" below). If you wish to use those items with an inverter, then choose a Pure Sine Wave inverter. If you mostly want to run lights, TV, microwave oven, tools, etc, a Modified Sine Wave inverter is fine for your needs.
    We often are asked if computers will work with Modified Sine Wave. It's been our experience that most (with the exception of some laptops) will work (though some monitors will have interference such as lines or a hum). However, if you have any doubt about any appliance, tool or device, particularly laptop computers and medical equipment such as oxygen concentrators, we recommend that you check with its manufacturer to be sure it is compatible with a Modified Sine Wave inverter. If it is not, choose one of our Pure Sine Inverters instead.
    The difference between them is the Pure Sine Wave inverter produces a better and cleaner current. They are also considerably more expensive. You might find it practical to get a small Pure Sine Wave inverter for any "special need" you may have, and also a larger Modified Sine Wave inverter for the rest of your applications.
     
  4. mickey69

    mickey69 Thread Starter

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  5. moz

    moz

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    I believe that the modified sine wave inverter might give problems to the pumps and that is why they are not recommended.
     
  6. lIghty

    lIghty

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    Thats correct Moz, as they are inductive. You might find a odd pump that will work off a "decent" mod sive inverter ok, but most time they start reattling.
     
  7. mickey69

    mickey69 Thread Starter

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    so the only option for safe power through an inverter for pumps is a 'pure' model?
     
  8. brentnorm

    brentnorm

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    In a nutshell, YES.
     
  9. lIghty

    lIghty

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    If you want piece of mind, Yes.
     
  10. RUAN

    RUAN

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    cool info
     
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