require sine wave inverter

deco81231007
deco81231007 Banned Posts: 1
in Solar Beginners Corner #1
Which household appliances require sine wave inverter?
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #2
    Re: require sine wave inverter

    Welcome to the forum!
    Not being sarcastic, rather I'm stating a truth - - - - it's trial and error. If a device can't handle MSW, you learn that when it fails, or when it emits smoke.
    Has mostly to do with the design of the internal power supply of the device.
    Generally items without electronics are safe, but it seems almost everything today has some level of electronics.
    Many items will work more or less fine. A few will give up the ghost. It's a game of Russian Roulette. And cost of the item is NOT a predictor.
    Some cheap items are worth trying. No big deal if they smoke. An $800.00 computer controlled front load washer is not worth the risk - - - unless you're rich, in which case you wouldn't be using a MSW inverter in the first place.
    In addition, items with induction motors, like fridges and freezers, consume about 20% more power when operated on msw, which results in the motor running hotter, which in turn can drastically shorten it's life. As well, the added vibrations within areas of the motor windings, caused by MSW, can damage the insulation of the windings and cause early failure.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,642 admin
    #3
    Re: require sine wave inverter

    As Wayne says... 80% will work fine, 10% will fail within hours, and 10%--who knows.

    Some folks have gone the two inverter route. A smaller TSW inverter for "critical" items (battery chargers, electronics, small/low power appliances, LED/CFL lighting, etc. which can run 24 hours of AC power per day and not waste much energy in the 24x7 inverter operation).

    And for big stuff (universal/brushed motors, circular saws, sump pumps, other electric motors that are not heavily loaded) get a cheap MSW inverter to run those.

    All About Inverters
    Choosing an Inverter - Home Power Magazine

    The small wall transformers and many small power supplies (wall warts, power cord bumps) do not like MSW power. Many times, you can tell because they run hot.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #4
    Re: require sine wave inverter

    Resistive load = no problem.
    Inductive load (transformer, AC motor) = possible problem.

    Even if the motor will run on MSW it's not going to like it. So contrary to what Bill said it is not a good idea to use MSW inverter on them.

    These days the MSW inverter's lower price isn't as much of an incentive to buy as the pure sine inverters are not as costly as they once were.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #5
    Re: require sine wave inverter
    Cariboocoot wrote: »
    Resistive load = no problem.
    Inductive load (transformer, AC motor) = possible problem.

    Even if the motor will run on MSW it's not going to like it. So contrary to what Bill said it is not a good idea to use MSW inverter on them.

    These days the MSW inverter's lower price isn't as much of an incentive to buy as the pure sine inverters are not as costly as they once were.

    agreed coot as the modsine inverter uses square waves which are rich in harmonics. these harmonics are not useful power in inductive loads, but will be dissipated in the form of heat in the windings. this means a higher power draw from the appliance and more heat dissipated in it.
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  • 2manytoyz
    2manytoyz Solar Expert Posts: 373 ✭✭✭
    #6
    Re: require sine wave inverter

    Inductive loads don't work as well, or not at all, on MSW. These include transformers, motors, variable speed devices, microwave ovens, etc.

    Things that do work rather well on MSW in my experience are computers, lights, TVs, most electronics, etc.

    A microwave oven will work on MSW, but it takes longer, and may have a slightly different sound. I had a conversion van that I installed a microwave oven and a MSW inverter. 5 years later, I traded it in, but kept the inverter. The microwave still worked perfectly after all that time of running on MSW exclusively. Yes, it did take a little longer, but it did work, and the microwave suffered no damage.

    At work we run a lot of telemetry, radio equipment, medical equipment, and computers, all from MSW inverters. No noise, and no noticeable difference in operation.

    chair3.jpg

    There's $100K worth of sensitive equipment in the base of this research chair, all running on MSW power. Any RF noise would trash our ECG and Cranial Doppler signals.

    There's no guarantee that a MSW inverter will run all your equipment without issues. But my point is don't assume it won't run your equipment. I've been using MSW inverters since the mid 90s. Very few items I've run across that showed any noticeable difference in performance.

    All that said, for the low cost of a true sine wave inverter, why risk it? In years past, they were prohibitively expensive. Now, they cost less than MSW used to. I have a Xantrex 1800W inverter that only cost $325. It'll run just about any 120VAC appliance. The waveform is cleaner than grid power.
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  • Susido
    Susido Registered Users Posts: 32 ✭✭
    #7
    Re: require sine wave inverter

    To help answer the original question, I can add only 1 household appliance to the list requiring pure sine wave: electric blanket.

    Over the last 7 years I've run just about everything else electrical (including a great many tools) that a normal North American consumer might own without any (obvious) problems on a MSW inverter. Although as previously mentioned, a microwave does runs noticeably different on MSW, particularly in terms of the sound they make. Nowadays I'd guess that a pure sine inverter of the equivalent size to mine (2500 watts/ 4500 peak) is only about twice as expensive (and will have better effiiciency) so when it comes time to replace mine I will likely buy a pure-sine wave inverter. But given the cost at the time, it wasn't something I really considered originally and I've glad I didn't because I've never needed one. Except for that dang blanket...
    Seasonally off-grid ... 468 Ahrs @ 48V (8 Rolls S-605 6v FLA batteries),  24 x 130watt panels, 6 x 260watt panels, 2 x Midnite Classic 150, Whizbang Jr., Magnum MS4448PAE inverter/charger, 2 x Honda eu2000i generators paralleled.


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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #8
    Re: require sine wave inverter

    it doesn't matter if you've used a modsine inverter or not as it does not change what i've said about them as that is fact.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #9
    Re: require sine wave inverter

    I've used an MSW inverter to run a refrigerator and to run a fan. Worked, but neither motor 'liked' it at all. The 'frige would clatter when it started as the motor struggled to get up to speed on a poor power waveform.

    Not recommended by me.
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  • davekr
    davekr Registered Users Posts: 1
    #10
    Re: require sine wave inverter

    I would recommend a pure sine wave inverter. There is a high chance that modified square wave inverters cause damage for devices like computers, digital clocks and other digital devices in long term use. Pure sine wave inverters literally provide power just like on grid. I have previous experience with modified square wave inverters damaging my computers. So for past many years I am using pure sine wave stativolt inverters at my home and office without any issues.
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #11
    Re: require sine wave inverter
    davekr wrote: »
    ... So for past many years I am using pure sine wave stativolt inverters at my home and office without any issues.
    The Stativolt website looks respectable, but others should note that they only mention CSA listing to Canadian safety standard(s) and so are possibly not available for legal use in the US.
    They may also meet the relevant US standards, but unless tested to those standards by CSA or some other recognized lab the do not meet the NEC and insurance requirements in the US.
    SMA SB 3000, old BP panels.
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