Can non-sinusoidal inverters damage household appliances

oz93666
oz93666 Registered Users Posts: 2
in Advanced Solar Electric Technical Forum #1
I recently bought a grid tie inverter without checking if it was pure sine wave.

Today I plugged it in and noticed my toaster was buzzing, then my induction cooker stopped working, latter started again.

Can non -sinusoidal inverters cause problems? If so which appliances are vulnerable? Fridges ?....Thanks
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  • peakbagger
    peakbagger Solar Expert Posts: 341 ✭✭✭
    #2
    Re: Can non-sinusoidal inverters damage household appliances

    Yes, they can and good luck trying to figure out what is and isn't going to survive.
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  • jebatty
    jebatty Solar Expert Posts: 56 ✭
    #3
    Re: Can non-sinusoidal inverters damage household appliances

    If i understand that non-sinusoidal means not pure sine wave, and the non-sinusoidal grid tie inverter is supposed to tie to the grid, is the grid ignorant of this fact and allows any proper voltage and pseudo-60 cps inverter device connect, and how does that impact the grid?
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #4
    Re: Can non-sinusoidal inverters damage household appliances

    A grid-tie inverter would be pure sine wave.

    I don't know what you bought, but it sounds like a cheap piece of junk. Or else it is not a grid-tie inverter but is connected to the grid anyway, resulting in even worse harmonic distortion than an MSW inverter would produce all on its own.

    Get rid of it.

    This is why all grid-tie installs are done with UL listed equipment plus proper plans, inspections, and approval. Somehow I suspect this is not the case here. Sounds like one of those plug-n-play pieces of junk sold all over the place that can never be legally installed.
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #5
    Re: Can non-sinusoidal inverters damage household appliances

    Sounds like something I'd run from, and fast!
    I'm wondering how it could override the grid it's tied to, so much that it's causing things to buzz and fail. Something is definitely NOT right here!
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #6
    Re: Can non-sinusoidal inverters damage household appliances
    waynefromnscanada wrote: »
    Sounds like something I'd run from, and fast!
    I'm wondering how it could override the grid it's tied to, so much that it's causing things to buzz and fail. Something is definitely NOT right here!

    It wouldn't be overriding the grid, it would just be filling the waveform full of distortion.
    The toaster buzzing sounds very much like out-of-sync waveforms, which would mimic higher frequency and RMS Voltage and result in some interesting vibrations in the heating elements. Toaster probably wouldn't suffer, but an awful lot of electronic gear would not take kindly to such a thing.
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  • peakbagger
    peakbagger Solar Expert Posts: 341 ✭✭✭
    #7
    Re: Can non-sinusoidal inverters damage household appliances

    Boy I missed the Grid tie part, :blush: run away quickly as a legit grid tie inverter is going to be pure sine wave as I believe that all it does is follows the utility rather than generating its own.
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #8
    Re: Can non-sinusoidal inverters damage household appliances
    oz93666 wrote: »
    I recently bought a grid tie inverter without checking if it was pure sine wave......

    If it is grid tie, it HAS to be pure sine, or very close to it, to be allowed to backfeed the grid.
    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 ,

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  • CDN_VT
    CDN_VT Solar Expert Posts: 492 ✭✭✭
    #9
    Re: Can non-sinusoidal inverters damage household appliances

    Did AnyONE ask if it was connected to the grid when it was being used ? if it was not maybe it was in search mode of ?? who NOOS :-) , but OP didn't leave much on their first post .


    VT
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #10
    Re: Can non-sinusoidal inverters damage household appliances
    CDN_VT wrote: »
    Did AnyONE ask if it was connected to the grid when it was being used ? if it was not maybe it was in search mode of ?? who NOOS :-) , but OP didn't leave much on their first post .


    VT

    Search or standby would not cause the symptoms described.
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  • Mountain Don
    Mountain Don Solar Expert Posts: 494 ✭✭✭
    #11
    Re: Can non-sinusoidal inverters damage household appliances

    The OP also dod not say "bought new". Maybe it is a POS and was bought used because the seller found out it was a POS.
    Northern NM, 624 watts PV, The Kid CC, GC-2 batteries @ 24 VDC, Outback VFX3524M
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  • CDN_VT
    CDN_VT Solar Expert Posts: 492 ✭✭✭
    #12
    Re: Can non-sinusoidal inverters damage household appliances

    TRUE , Could be the appliance companys have released a new way of planned obsolescence :-)

    VT
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  • oz93666
    oz93666 Registered Users Posts: 2
    #13
    Re: Can non-sinusoidal inverters damage household appliances
    mike95490 wrote: »
    If it is grid tie, it HAS to be pure sine, or very close to it, to be allowed to backfeed the grid.

    I bought this on ebay, $150 1kw new . The listing says pure sine wave..... http://www.ebay.co.uk/itm/1000W-Micro-Grid-Tie-Inverter-W-MPPT-Stackable-For-Grid-Tie-Solar-System-18V-/151484722952?pt=LH_DefaultDomain_0&hash=item2345316f08

    ... but in the 14 page manual it says nothing about this.

    My knowledge of electronics says you are correct that it should be pure sine wave, but why does my toaster buzz, when inverter is stable and working? this must be a distorted wave surely.

    If all grid ties are pure sine wave , then I guess it's OK to buy the cheapest.... as long as it has no fan, critters get in through the fan port and cause problems.
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  • peakbagger
    peakbagger Solar Expert Posts: 341 ✭✭✭
    #14
    Re: Can non-sinusoidal inverters damage household appliances

    You may have a tough time sorting out answers as many of posters on this site are based in the US where this type of direct plug in inverter is illegal. These cheap Chinese inverters do have the reputation of premature failure and other issues. When they fail, they could cause a fire so if you insist on using it better make sure its away from anything that may burn. Very soon the initial price savings will be made up by either damaged appliances, replacement inverters or loss the life an property when the house burns down.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #15
    Re: Can non-sinusoidal inverters damage household appliances

    Anyone who expects a $150 1kW grid-tie inverter to work is dreaming.
    Get rid of it before something worse happens.

    Buy quality, or pay the price twice.
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #16
    Re: Can non-sinusoidal inverters damage household appliances
    Cariboocoot wrote: »
    Anyone who expects a $150 grid-tie inverter to work is dreaming.

    ...all those people with micro inverters???
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #17
    Re: Can non-sinusoidal inverters damage household appliances
    Photowhit wrote: »
    ...all those people with micro inverters???

    Are $161 and not 1kW.

    I shall amend my post to satisfy the annoyingly pedantic.

    He bought a piece of junk which doesn't work.

    Anyone who disagrees with this we shall consider to be offering to pony up the money to replace and repair any and all damage which may result from the use of same. Otherwise, shut up.
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #18
    Re: Can non-sinusoidal inverters damage household appliances
    Cariboocoot wrote: »
    Otherwise, shut up.

    Sorry, just trying to make light of the comment....
    ...hope you didn't wake up on the wrong side of the bed!

    Agreed, they are very dangerous in general...
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • ATSman
    ATSman Registered Users Posts: 3
    #19
    Re: Can non-sinusoidal inverters damage household appliances

    I had the same question after I bought a 600W cheap (China) inverter on eBay for around $125
    I then bought a used Fluke 43B hand held scope to look at the waveform with the inverter tied in
    to my house and found no difference than just measuring the utility wave form: a perfect sign wave.
    I know most regular (non GTE) type inverters put out a square wave which does not bother most types of loads. Not
    sure about motors, though. Pretty sure all GTE put out a good sine wave, otherwise they could not
    synchronize with the utility.
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  • 706jim
    706jim Solar Expert Posts: 522 ✭✭✭✭
    #20
    Re: Can non-sinusoidal inverters damage household appliances

    If its a modified sine it will devour DeWalt battery tool chargers.

    Most everything else will work, but may buzz.
    Island cottage solar system with appriximately 2500 watts of panels, 1kw facing southeast 1.3kw facing southwest 170watt ancient Arco's facing due south. All panels in parallel for a 24 volt system. Trace DR1524 MSW inverter which has performed flawlessly since 1994. Outback Flexmax 80 MPPT charge controller four 467A-h AGM batteries. Insignia 11.5 cubic foot electric fridge 1/4hp GSW piston pump. My 31st year.
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #21
    Re: Can non-sinusoidal inverters damage household appliances
    706jim wrote: »
    If its a modified sine it will devour DeWalt battery tool chargers.

    Most everything else will work, but may buzz.

    I'm sorry, but this is NOT true!!! I checked when I bought my set circa 2001, to build my 'A' frame, the model being introduced then, was fine on Modified Sine wave inverters! I had read that there were problems before when checking on the web and actually contacted DeWalt for confirmation and got it! Perhaps the proof is the Framed 'A' frame and the batteries and charger still working when I built my cabin 4-5 years later. Though at that point I had switched to a pure sine wave.

    FWIW many other battery chargers do have a problem with modified sine wave current. You may see 'noise' in the old analog TV's and video displays. It is 'harder' on electronics and motors will run less efficiently.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #22
    Re: Can non-sinusoidal inverters damage household appliances

    To be destroyed - - or not - - by MSW inverters depends to a very small part on the quality of the inverter (some have outputs a bit less square than others), but mostly it depends on the design of the power supply in the device connected to the inverter. Some power supplies are more tolerant of less than a true sine wave supply.
    SO - - - how to determine if MSW will cause your device to emit snaps, crackles, pops, stink and smoke, or perhaps just up and die? Simple. Connect it, turn it on and see what happens. :D
    Of course induction motors and transformers always use more power and run hotter on MSW.
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  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    #23
    Re: Can non-sinusoidal inverters damage household appliances

    I have 3 'identical' DeWalt chargers and on an old 400w MSW inverter one of them started to smell of the magic smoke. I quickly shut it down and now that charger still appears to work but does not do a full charge of any of the various batteries I tried..They just run out of steam in half the time......YMMV

    ps have switched to Makita tools with Li batteries
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
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  • 706jim
    706jim Solar Expert Posts: 522 ✭✭✭✭
    #24
    Re: Can non-sinusoidal inverters damage household appliances
    westbranch wrote: »
    I have 3 'identical' DeWalt chargers and on an old 400w MSW inverter one of them started to smell of the magic smoke. I quickly shut it down and now that charger still appears to work but does not do a full charge of any of the various batteries I tried..They just run out of steam in half the time......YMMV

    ps have switched to Makita tools with Li batteries

    The DeWalt chargers I have don't have any sort of transformer coils in them. Pick one up and it feels like an empty plastic case; just a capacitor or something inside.

    Chargers with a coil inside seem to work fine on my old Trace DR1500.

    Makita is one such company.

    So my DeWalts stay in the city to charge off the grid and my "island" tools have coils in the chargers.
    Island cottage solar system with appriximately 2500 watts of panels, 1kw facing southeast 1.3kw facing southwest 170watt ancient Arco's facing due south. All panels in parallel for a 24 volt system. Trace DR1524 MSW inverter which has performed flawlessly since 1994. Outback Flexmax 80 MPPT charge controller four 467A-h AGM batteries. Insignia 11.5 cubic foot electric fridge 1/4hp GSW piston pump. My 31st year.
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