MSW: Modified Square Wave or M. Sine Wave Discussion (trimmed from original thread)

BB.BB. Super Moderators, Administrators Posts: 32,007 admin
john p wrote: »
And off topic why do Americans continue to keep saying "if its a cheap MSW it most likely a square wave inverter"???? :confused:

Because they are???? :confused:

I am not sure what you are saying here... MSW = Modified Square Wave -- although the marking types like to call it a Modified Sine Wave -- which it really is not.

The Trace/Xantrex SW family was a different animal... Much closer to a True / Pure Sine Wave inverter output than most MSW types--but still did not meet the typically <5% Total Harmonic Distortion that is usually used as the cutoff point between "MSW" and "TSW" inverters. [correction: I looked up the specs. later in this thread and the "SW" family is rated for <5% THD--which in terms of electric power does meet the "True Sine Wave" definition--BB.]

Or are you just observing that the Yank's (not including the Canadian's, Mexico, and the rest of central/south America--eh?) are members of the Department of Redundancy Department?

-Bill
Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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Comments

  • john pjohn p Solar Expert Posts: 814 ✭✭✭
    Re: UPS for modified sine wave system?

    Or are you just observing that the Yank's (not including the Canadian's, Mexico, and the rest of central/south America--eh?) are members of the Department of Redundancy Department?
    YES
    Because a squarewave inverter cant EVER be a modified square wave inverter,, Simply because of the wave form ITS NOT MODIFIED..

    inverters can only ever be either..

    Square wave. the (worstest ones) capable of damaging just about any piece of electronics or electric motors
    Modified Sine Wave.. usable for most applications.. and despite what is many times said dont usually destroy electric motors but may make them buzz a it. I had a refigerator that was 4 yrs old before runn ing it on MSW for another 4 years and it now back on grid 3 yrs and still ok.. all our cheap chinese ceiling fans run of a MSW ok and have do so for years
    True sine wave.. best for delicate electronics . but less effecient than MSW (higher idle current use also) and more expensive.

    This is not all there is to inverters as there are different types of sine wave ones.

    BB You are one of the few that seems to know this. others get it wrong.

    I am not sure what you are saying here... MSW = Modified Square Wave -- although the marking types like to call it a Modified Sine Wave -- which it really is not.
  • mike95490mike95490 Solar Expert Posts: 9,359 ✭✭✭✭✭
    Re: UPS for modified sine wave system?
    john p wrote: »
    And off topic why do Americans continue to keep saying "if its a cheap MSW it most likely a square wave inverter"???? :confused:

    Because they generally are. MSW= modified SQUARE wave, 3 steps instead of 2. That's the modification.

    The SW, with it's +30 steps, is MUCH more like a sine wave, than a square wave, and nearly everything should run fine on it.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: UPS for modified sine wave system?
    [FONT=Fixedsys]Square wave:[/FONT]
    
    [FONT=Fixedsys]+120v -------     [/FONT][FONT=Fixedsys]-------
          |     |     |     |
    0v    [/FONT][FONT=Fixedsys]|     |     |     |
          |     |     |     |
    -120v       [/FONT][FONT=Fixedsys]-------     [/FONT][FONT=Fixedsys][/FONT][FONT=Fixedsys]-------[/FONT]
    
    
    [FONT=Fixedsys]MSW (Modified Square Wave):[/FONT]
    
    [FONT=Fixedsys]+164v  ----        [/FONT][FONT=Fixedsys]----
           |  |        |  |
    0v    [/FONT][FONT=Fixedsys]--   --     --   --  (shoulder in MSW)
          |      |   |       |
    -164v        [/FONT][FONT=Fixedsys]-----       [/FONT][FONT=Fixedsys]----[/FONT]
    

    Anyway, my rough ASCII drawing of the difference between MSW and SW wave forms.

    MSW will probably power 80-90% of the devices out there OK (perhaps a little warm, a little "buzz", timers/clocks may not work correctly). The other 10% or so--frequently little warning before they fail.

    A couple of FAQ's from NAWS's Inverter Page:

    All About Inverters
    Choosing an inverter for water pumping

    They will do a better job of explaining that I can...

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • john pjohn p Solar Expert Posts: 814 ✭✭✭
    Re: UPS for modified sine wave system?

    MIKE 90045 You somehow have it completely wrong..
    To try to put it again simply.. if its a SQUAREWAVE INVERTER . it is NOT a MSW.
    IF the word modified is used to describe an inverter, Then by defination it must be a MODIFIED SQUARE WAVE .. It cant be a simple Square wave inverter.
  • mike95490mike95490 Solar Expert Posts: 9,359 ✭✭✭✭✭
    Re: UPS for modified sine wave system?
    john p wrote: »
    MIKE 90045 You somehow have it completely wrong..
    To try to put it again simply.. if its a SQUAREWAVE INVERTER . it is NOT a MSW.
    IF the word modified is used to describe an inverter, Then by defination it must be a MODIFIED SQUARE WAVE .. It cant be a simple Square wave inverter.

    Actually, there is some marketing weenie somewhere, that is selling square wave inverters, as modified sine wave. VERY Modified.

    As BB's sketch points out, most inverters that call themselves ModSineWave, more closely resemble a ModSquareWave. Sales pitch plays on the Pure Sine part of the waveform, without actually saying it. Like Snake Oil Salesmen.

    most $95 inverters outputs more closely resemble BB's sketch, than anything else.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: UPS for modified sine wave system?

    kicking this around a bit i follow what johnp is trying to say and he's going by semantics. the square wave waveform is not modified. what really should've be said is that it is a modsine and not a modsquare. i argue this as a square wave by definition is a sine wave modified by adding all of the harmonics to it. for this forum all modified sine wave inverters would basically cover all of those not of the sine wave definition as applied to inverters using 5% or less thd. this also means that not all modsquare wave inverters would fit the same definition as this would exclude a pure square wave inverter.

    note in the pic of the square wave and the msw wave that both are technically square waves as the only differences are the duration of the waves(time) and the amplitude for the msw and the waveform itself stays very much a squarewave. calling this a modsquare wave would technically be wrong to do as that would indicate changing the waveform itself which hasn't happened.
  • john pjohn p Solar Expert Posts: 814 ✭✭✭
    Re: UPS for modified sine wave system?

    BBs sketches are correct..
    Really there is no such thing as a modified sine wave inverter,, reason.. if it started out as a sine wave why would you want //try to modify it ?????/:confused:
    MSW inverters all start out with the first section of the inverter delivering a Square wave, the cheap ones sell them like that the next step up is to modify the square wave so it more resembles a sine wave....
    But by reading some of the other posts there are manufactures making 30 step MSW inverters.. but its an exercise in futility.. it be simpler and easier to just make a true sine wave one...
    Or they just doing it bacause thay can? or because they think the 30 step square wave is impressive to customers??
    There is no way I would attempt to design such a device when it is easier to make a sine wave inverter.
  • john pjohn p Solar Expert Posts: 814 ✭✭✭
    Re: UPS for modified sine wave system?

    Its hard to exactly explain all about the differences between mod sq wave ,sine wave etc.. l even though I know a lot about the design of them, (designed my first squarewave one 300watts about 60 %effecient??? in about 1984)

    Mabe if square waves are looked at like digital switching its either on or off so a true squarewave is just the switching device switching the volts on or off but with a set on and off time (50%),,
    A sine wave is more like analogue. it has a rise time and peak then a decay time.
    Because of this it takes more circuitary to do this,(more expense) also because of the slow rise time it generates more heat.. larger heatsink/fan(more expense)

    To try to keep the cost of sine wave inverters down very high frequency switching is used and that allows small transformers (les use of expensive copper) but this creates its own problems of high output impedance compared to grid power. so its harder for an inverter to start motors.. the best ones use much lower frequency switching and bigger and heavier transformers these start motors much better but cost usually double the price of "normal" sine wave inverters..

    Sorry to the original poster that was not asking anything about this subject.. I really wanted to just try to get people to stop calling cheap square wave inverters cheap MSW inverters. it just anoys me..
  • Vance GVance G Registered Users Posts: 7
    Re: UPS for modified sine wave system?
    john p wrote: »

    Sorry to the original poster that was not asking anything about this subject.. I really wanted to just try to get people to stop calling cheap square wave inverters cheap MSW inverters. it just anoys me..


    Hey, no problemo. I enjoy a vigorous discussion of just about anything.

    I tend to agree that the "marketing" way of glossing over just what kind of waveform you get is inaccurate from an engineering standpoint...

    But Marketing always seems to win out over Engineering.

    Just ask Dilbert.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: UPS for modified sine wave system?

    my comments in bold.
    john p wrote: »
    BBs sketches are correct..

    i never said his sketches were wrong. i only argued his use of the term modified square wave as you did. i find it amazing that in my agreeing with you that you would in turn use and argue it against me.

    Really there is no such thing as a modified sine wave inverter,, reason.. if it started out as a sine wave why would you want //try to modify it ?????/:confused:
    MSW inverters all start out with the first section of the inverter delivering a Square wave, the cheap ones sell them like that the next step up is to modify the square wave so it more resembles a sine wave....

    you are wrong that there is no such thing as a modified sine wave. as what i defined for the square wave is quite exactly what a square wave is. this has no bearing on what is easier to create or go to as a sine wave is a square wave without the harmonics. as applied to inverters, to step square waves of shorter duration can average to a sine wave with x% amount of total harmonic distortion. we call it sine wave when it is 5% thd or lower as per utility requirements. for the record msw inverters do not start out as sine wave inverters.

    But by reading some of the other posts there are manufactures making 30 step MSW inverters.. but its an exercise in futility.. it be simpler and easier to just make a true sine wave one...
    Or they just doing it bacause thay can? or because they think the 30 step square wave is impressive to customers??
    There is no way I would attempt to design such a device when it is easier to make a sine wave inverter.
  • icarusicarus Solar Expert Posts: 5,433 ✭✭✭✭
    Re: UPS for modified sine wave system?

    To those of us who wouldn't know a square wave from a Tsunami wave, we (ME!) tend to infer that MSW (in whatever derivation!) is an inferior Sine Wave form, and ergo we (I) tend to call it MSW a "MODIFIED SINE WAVE" inverter. In general, we (I) don't care if it is a modified square wave, or stepped square wave, or a surfers wave! The reality is I know I can plug my stuff into "pure sine wave" inverters, and might have trouble with MSWs regardless of the wave form.

    Tony;)
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: UPS for modified sine wave system?

    you are right tony as anything that does not qualify as sine wave for the intent of this forum is a modified sine wave. modified square wave is, by semantics, not including both the sine wave and the square wave and you call it all msw anyway.:confused::cry::p
    enuf said on it.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: UPS for modified sine wave system?

    Hey, you really want to get the argument going? A 'Modified Sine/Square Wave' is actually a 'stepped square wave'. Some of them have more steps, which is why they perform better; more closely mimics a sine wave. :p

    Considering the price of sine wave inverters these days, the ol' MSW is soon to go the way of the dinosaur.
  • john pjohn p Solar Expert Posts: 814 ✭✭✭
    Re: UPS for modified sine wave system?

    To start with Neil I never ment to imply you said his sketches were wrong.. I was just stating a fact.
    I stand by this statement as it is a simple fact if you design a sine wave inverter why would you modify it..the front end design of a sine wave inverter is totally different to a squarewave inverter.Well at least the ones ive worked on and had to do part of the design,, mabe the ones you have designed are not different.
    Really there is no such thing as a modified sine wave inverter,, reason.. if it started out as a sine wave why would you want //try to modify it ?????/ True sine wave inverters all start with an IC that generates a 50 or 60 hz sinewave.. well at least everyone I have seen..mabe you do it the hard way and generate a square wave and then use ICs to create 30 or more steps to create a almost sine wave????

    for the record msw inverters do not start out as sine wave inverters.I think I already said this ,,,
    MSW inverters all start out with the first section of the inverter delivering a Square wave, the cheap ones sell them like that the next step up is to modify the square wave so it more resembles a sine wave....

    Considering the price of sine wave inverters these days, the ol' MSW is soon to go the way of the dinosaur. ???
    Well that may be true in USA but ceatainly not in Aus
    here are the MSW price of a 1000w inverter au$359
    here is the price of a true sinewave 1000 w inverter au$799
    Here is price for low frequency 1000 w inverter au$1299
    To me that is a LOT of difference,, all those from same manufacturer
  • icarusicarus Solar Expert Posts: 5,433 ✭✭✭✭
    Re: UPS for modified sine wave system?

    Technical semantics. A Zoologist is pronounce Zoe-ologist, but most folks pronounce it wrong. I don't think the inference is anyone would design (or has designed) a sine wave inverter, and then modified it to become a square wave inverter, as I can't imagine that there would be any point in that. So I stand by my comment, those of us no techies think that MSW refers to anything other than a pure sine wave piece of hardware!

    Tony
  • john pjohn p Solar Expert Posts: 814 ✭✭✭
    Re: UPS for modified sine wave system?

    Tony Tony Tony to call a squarewave inverter a MSW inverter is just plain WRONG.
    You do well with that idea here in Philippines where they call any type of grid disturbance a "brownout" no matter if it just short term slightly low voltage or complete loss of electricity..To them one the word fits all situations..It seems same for you and so many other people.. even ones that should know better.
    Another place you be happy with one word fits all in Russia when I was there I found all 4 wheel drives no matter what make were called "jeeps"

    By defination a modified sine wave inverter Must have startted out as a sine wave inverter... if that not true then how could it ever become a modified one?:roll:

    A modified F250 Ford never came off the production line as a Chev Corvair:p
  • icarusicarus Solar Expert Posts: 5,433 ✭✭✭✭
    Re: UPS for modified sine wave system?

    Geez! Why am I even wasting energy on this? But here goes. It is not the INVERTER that is modified, but rather the wave form itself, rather than producing a clean sine wave, the inverter produces a modified square wave, aka a MODIFIED SINE WAVE!!!

    Tony
  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: UPS for modified sine wave system?

    OK--Terms--From the link to the 2001 Home Power Article that is hosted by NAWS as a FAQ:
    A “modified sine wave” inverter is less expensive, but it
    produces a distorted square waveform that resembles the track of a pendulum being slammed back and forth by hammers. In truth, it isn’t a sine wave at all. The misleading term “modified sine wave” was invented by advertising people. Engineers prefer to call it “modified square wave.”
    The correct term for MSW is Modified Square Wave--Modified Sine Wave is just a marketing term.

    The old Trace/Xantrex SW Inverter was not a three state MSW inverter but got reasonably close to a sine wave--and did meet the 5% THD cutoff that is usually used around here to define a TSW/PSW inverter.
    Total Harmonic Distortion < 5%
    It accomplished this with the "34 to 52 steps per cycle" to approximate a true sine wave output.

    A MSW wave form is a "cheat" that is relatively easy to accomplish with several inverter driver circuits... The "square wave" would have been a pair of drivers "on" then they turn off and the other pair (opposite polarity) turn "on"... A modified square wave output is accomplished by inserting a period when both sets of drivers are "off" for a period of time to produce the zero volt shoulder of the MSW wave form.

    So--this is why it is properly called a Modified Square Wave or if you prefer a pulse train (which can mean almost anything).

    Modified Sine Wave is just a marketing term to confuse the fact that a MSW inverter does not have anything near a true sine wave output.

    It is not possible through just inductive/capacitive filtering to, practically, change a Square Wave or MSW wave form into a sine wave.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • john pjohn p Solar Expert Posts: 814 ✭✭✭
    Re: UPS for modified sine wave system?

    BB seems to understand what its all about.
    I carus I really thought you and the others would be smart enough to understand when I said the inverter is modified you would understand I didnt mean the outside case . I really thought all would understand I ment "The circuitry that generared the sine wave...

    It is not the INVERTER that is modified, but rather the wave form itself, rather than producing a clean sine wave, the inverter produces a modified square wave, aka a MODIFIED SINE WAVE!!!
    By defination a modified sine wave inverter Must have startted out as a sine wave inverter... if that not true then how could it ever become a modified sinewave
    But to add the words you need to understand I have re written? it

    By defination a modified sine wave inverter Must have started out with the circuitary that generates the sine wave... if that not true then how could it ever become a modified (circuit) inverter

    This is the end its way passed it really.
  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: MSW: Modified Square Wave or M. Sine Wave Discussion (trimmed from original threa

    I cannot help but believe that we are somehow talking past each other... :confused:

    Anyway, I gave this its own thread to continue (or not) and keep the original thread more or less on topic:

    UPS for modified sine wave system?

    -Bill (as moderator) B.

    PS: And this diversion was my fault--Sorry. :blush:
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • icarusicarus Solar Expert Posts: 5,433 ✭✭✭✭
    Re: MSW: Modified Square Wave or M. Sine Wave Discussion (trimmed from original threa

    Bill has it right, MSW is a marketing term, and in fact works quite well for non-technical folks to tell the difference between inverter output wave forms. Most of us don't care (nor could really explain!) if it is a square wave, modified square wave, stepped square wave, surfers wave, tidal wave, tsunami wave, or football stadium wave inverter! All we care about is if it is a "pure" or "True" sine wave inverter, and ergo know that our stuff won't go up in smoke! That is all us simple end users care about!

    Second, I know of, nor can I imagine an inverter that "started with a sine wave inverter" then became a square wave or modified square wave inverter. That would be silly.

    I believe I will sing off on this semantic argument!

    Icarus
  • john pjohn p Solar Expert Posts: 814 ✭✭✭
    Re: MSW: Modified Square Wave or M. Sine Wave Discussion (trimmed from original threa

    I said before in my last post I not say no more but promise after this one no more about this ..
    but think of this even if you have no interest in using the correct terms for things

    if you have a modified chev corvette it MUSThave started out as a chev corvette
    if you have a modified sine wave it MUST have started out as a sine wave
    if you have a modified square wave it MUST have started out as a square wave
    if you have a square wave inverter it Must have started out as a squarewave and was NEVER modified..

    If any you people want to call things by incorrect names .. you are free of course to do so, but it would be nice I feel if people that know the facts try to explain them to people that dont to try and help them learn.:D

    thank you BB your input was what I consider correct..
  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: MSW: Modified Square Wave or M. Sine Wave Discussion (trimmed from original threa

    Perhaps the confusion is I posted both Square Wave and a MSW Wave drawings and people where not clear with respect to which drawing they were typing about at times--Plus I made the mistake of not checking the specs. for the old Trace SW inverters and assumed that they were not TSW (per the <5% THD definition). Trace/Xantrex "SW Inverters" are TSW by the THD definition...

    I am not sure there are any true square wave inverters out there anymore (other than maybe some very small/cheap versions). The difference between a true square wave and a stepped square wave (a contradiction in terms itself :p ) driver electronics is small.

    It looks like the issue is the use of Modified to imply that something is one thing first then "changed" to something else later.

    Whereas the "American" use of Modified is simply a verbal description of the output wave form (think of a standard square wave with an average voltage of Zero--i.e., AC with zero offset--but with "shoulders" at 0 volts--and does not imply (at least in "my" mind--what little is left of it) any cause or effect in the actual creation of the output wave form.

    I understand that John P is from Australia--but perhaps this quote covers it all:
    • England and America are two countries separated by a common language.
    George Bernard Shaw
    Irish dramatist & socialist (1856 - 1950)
    I am truly sorry if anyone was upset by my failed attempt at a short humorous aside with the first post in this thread. :blush:

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: MSW: Modified Square Wave or M. Sine Wave Discussion (trimmed from original threa

    Let's point the finger of blame for terminology confusion exactly where it belongs: at the marketers! (As usual.)

    In their hands, Multiple Square Wave (stepped square wave) became Modified Square Wave and then Modified Sine Wave for the sole and express purpose of tricking an unwitting public into thinking an MSW was a reasonable substitute for sine wave. It gets even more confusing when you consider there is no industry standard for how many 'steps' is acceptable. Although I agree with Bill that there are probably no 'single square wave' inverters available these days, the difference between 'three steps' and 54 is significant.

    This accounts for why some MSW inverters will give satisfactory performance and some won't. It all depends on the particular inverter and the application it's put to.

    John has my sympathies; he has to buy with Australian $ which are even more worthless than our CDN $! :p
  • mike95490mike95490 Solar Expert Posts: 9,359 ✭✭✭✭✭
    Re: MSW: Modified Square Wave or M. Sine Wave Discussion (trimmed from original threa

    John has my sympathies; he has to buy with Australian $ which are even more worthless than our CDN $! :p

    The US $ is working hard to catch up !
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • KamalaKamala Solar Expert Posts: 452 ✭✭
    Re: MSW: Modified Square Wave or M. Sine Wave Discussion (trimmed from original threa

    Geeez... Kinda sad I missed the dust up. Anyway, my POV:

    In the beginning there was the BIG NOTE. It was a sine wave. Everything that exists today is a result of modifying the BIG NOTE!

    Apologies to Frank Zappa. :D
  • john pjohn p Solar Expert Posts: 814 ✭✭✭
    Re: MSW: Modified Square Wave or M. Sine Wave Discussion (trimmed from original threa

    Bill my whole point right from the beginning was exactly as you put it..
    It looks like the issue is the use of Modified to imply that something is one thing first then "changed" to something else later.

    Here in Australia if something is called modified well that is what it means,, nothing else.
    If you have a MODIFIED Ford Edsel it MUSThave been manufactured in the first place as a Ford Edsel..

    As for the Aussie dollar it is not that much below the USA dollar about 93 cents to the USdollar.
    But no matter what the difference the cost of true sine wave inverters here is double that of MSW inverters
    And low frequency ones about another 50% above that.

    Someone said you cant buy square wave inverters . yes you can they are usually the very low cost below 150 w ones. guaranteed to destroy any switchmode plug pak/wall wart
    But about 4 yrs ago bought the "worstest " squarewave inverter for a project in Philippines And couldent get a MSW or sine wave one in the town we were in.
    it was rated at 1000 watts but could just manage 380 w it consumed 3 amps on idle, it came supplied with input cables about #10 size with 10a clips on the ends and the inverter had tiny plastic"no metal insert " screw on connectors.
  • KamalaKamala Solar Expert Posts: 452 ✭✭
    Re: MSW: Modified Square Wave or M. Sine Wave Discussion (trimmed from original threa

    Genomes are routinely and randomly modified (by what mechanism is debatable) and have resulted in entities (ourselves) that can create the means (economic engines, computers, internet & will) to exchange ideas as we are doing NOW. Trilobites to Homo Sapiens Sapiens. Now that is a modification! Or, perhaps more simply, an evolution. By definition, evolution is modification. Or, if you prefer, evolution can only occur by means of modification (of genes.) That is, only if you buy into the E theory. Still, this is really just semantics. BB was right to quote GBS.

    I now claim to have an ESW. Evolved Sine Wave inverter. :-)
  • john pjohn p Solar Expert Posts: 814 ✭✭✭
    Re: MSW: Modified Square Wave or M. Sine Wave Discussion (trimmed from original threa

    what ?? you evolved from a sine wave inverter??I now claim to have an ESW. Evolved sine wave inverter

    amazing
  • KamalaKamala Solar Expert Posts: 452 ✭✭
    Re: MSW: Modified Square Wave or M. Sine Wave Discussion (trimmed from original threa

    No. I just claim to have one. How it evolved, I don't know. I think it came from the BIG NOTE.:roll:
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