MSW inverter ever ruin any of your appliances?

Mike at Energy Commission
Mike at Energy Commission Solar Expert Posts: 50 ✭✭✭✭
in Off Grid Solar & Battery Systems #1
I am new to this so I may be way off base with this question, however,from what I read it is possible for some electronics and appliances to overheat be damaged from using a modified sine wave inverter. Has anyone ever had their electronics or appliances ruined by a MSW inverter?
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #2
    Re: MSW inverter ever ruin any of your appliances?

    None in the last 20 years that I know of in the 50 + systems that know have them. The only thing I am aware of are the newest Refrigerators that have a computer board instead of a analog timer. Certain digital clocks have always had a problem with them ( Run fast or slow ). Ceiling fans buzz a lot on them, but run fine.

    TWS is cheap these days, I'd spend the extra if I was buying a new one.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #3
    Re: MSW inverter ever ruin any of your appliances?

    I have had small transformers (for portable devices) overheat to where they were hot to the touch/smelled hot.

    I would usage a Kill-a-Watt meter or a current clamp meter and measure the current used... If the device used about the same amount of current on MSW as TSW (true sine wave inverter or utility power), then the devices are probably OK... If they use 20% or more current--I would worry. If the device is small/light weight/made of plastic, then I would really worry (would not dissipate the extra heat well).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #4
    Re: MSW inverter ever ruin any of your appliances?

    I've had the power supply in two breadmakers go up in smoke on MSW, and I've had 12 volt rechargeable drills not charge properly at all on MSW.
    I've also had one of the resistors in the power supply in my Kil-A-Watt run hot on MSW, but not on pure sine. The heat could be felt through the case after 2 to 3 minutes, but not on PS. I now no longer use MSW.
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #5
    Re: MSW inverter ever ruin any of your appliances?

    Yeah, and I have had all the same run perfect on MSW as does most every Boat I work on, all have Trace, Heart Interface, Xantrex or Magnums, never had a issue with anything but anything with a digital clock. Now something you buy for $49 from e-bay might be different.

    That said, all MSW is not the the same on all inverters, it depends on the number of steps , just like TWS. Most TWS is between 34-52 steps and MSW is somewhere between 2 and something.
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  • techntrek
    techntrek Solar Expert Posts: 1,372 ✭✭✭
    #6
    Re: MSW inverter ever ruin any of your appliances?

    Lots of talk of built-in chargers in shavers having problems but I've never tested it. However, I have multiple X-10 controllers and a test on one of them caused it to get hot very fast on MSW. I unplugged it within 10 seconds before any damage was done.
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
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  • ChrisOlson
    ChrisOlson Banned Posts: 1,807 ✭✭
    #7
    Re: MSW inverter ever ruin any of your appliances?
    Mike at Energy Commission wrote: »
    I am new to this so I may be way off base with this question, however,from what I read it is possible for some electronics and appliances to overheat be damaged from using a modified sine wave inverter. Has anyone ever had their electronics or appliances ruined by a MSW inverter?

    We had a MSW inverter here for over 7 years and never had any problems with any of our stuff, including the well pump, computers or TV set. Ceiling fans were a bit noisy on it. Our old microwave with a dial on the front that you turn for the minutes was fine. But then my wife bought a new microwave with digital clock and buttons on it. The transformer in the new microwave did not like MSW at all and it made a lot of noise. I don't think that was good for the microwave, but it never seemed to hurt it.

    We could never use digital clocks with the MSW because they would gain time. We had battery operated clocks.

    We never knew how much extra noise some motors made (like furnace blower) on MSW until we got our first SW inverter. It was a dramatic improvement and all our stuff was a lot happier.
    --
    Chris
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #8
    Re: MSW inverter ever ruin any of your appliances?
    ChrisOlson wrote: »

    We never knew how much extra noise some motors made (like furnace blower) on MSW until we got our first SW inverter. It was a dramatic improvement and all our stuff was a lot happier.
    --
    Chris
    That's been my experience as well, and apart from the two breadmakers, nothing was ruined, however, like in your situation, everything was so much happier on SW, and the removal of mental stress, wondering what if anything was getting damaged, and knowing things weren't operating happily on MSW, that I'd never go back to MSW except in an emergency. SW means no possible damage due to MSW, no MSW induced stresses and the resulting buzzing in the devices in operation, and peace of mind. In hindsight, I initially went with MSW because of cost, but it ended up costing me more in the long run. But we all live and learn.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #9
    Re: MSW inverter ever ruin any of your appliances?

    As Blackcherry pointed out not all MSW inverters are the same, nor is every type of whatever you plug in to it. It's like going to the casino: might work, might not work, might work but not well, might send out smoke signals.

    And it's funny but whereas manufacturers are willing to publish specs when their unit's THD is +/-3% they tend to be reticent to let you know if it's +/-30%. :roll:
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #10
    Re: MSW inverter ever ruin any of your appliances?

    And don't forget the extra 20% or so, of power consumed because of MSW on inductive loads. Needing 20% less PV may pay for the pricey TSW inverter.
    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

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  • ChrisOlson
    ChrisOlson Banned Posts: 1,807 ✭✭
    #11
    Re: MSW inverter ever ruin any of your appliances?
    Cariboocoot wrote: »
    they tend to be reticent to let you know if it's +/-30%. :roll:

    That works just like the Head Politician in Washington. If it ain't good it's irrelevant. :D
    --
    Chris
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  • peakbagger
    peakbagger Solar Expert Posts: 341 ✭✭✭
    #12
    Re: MSW inverter ever ruin any of your appliances?

    The publisher of Home Power used to occasionally mention "the list" they kept on their wall of equipment incompatible with MSW inverters. They have stated the list is no longer of much value as most have installed pure sine wave inverters. I dont think MSW inverters would kill equipment outright, rather it might make then die a premature death.
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #13
    Re: MSW inverter ever ruin any of your appliances?
    peakbagger wrote: »
    I dont think MSW inverters would kill equipment outright, rather it might make then die a premature death.

    That wasn't the case with my two breadmakers. Both had, instead of a transformer to provide the low voltage to logic circuits, a power supply that consisted of a capacitor in series with a resistor, a couple of diodes, one to charge the "filter" capacitor, the other to discharge the AC capacitor on the next negative AC mains cycle, and a zeener diode to hold down and control the DC voltage. Works perfect on SW, but on MSW, all the sharp spikes and sharp corners causes the inline capacitor to "pass" way too much current, very quickly overheating the inline resistor and the zeener diode until the magic smoke comes out and everything stops.
    The Kill-A-Watt has the same style power supply, and to enable it to operate on MSW, the inline resistor has been changed to a much higher wattage rating. Likewise the zeener was upgraded. The first Kill-A-Watt units would burn out on MSW, and since they were so often used with solar systems on MSW, the manufacturer made the changes. But you can within a minute feel the case of the K-A-W getting warm when operating on MSW. It doesn't get warm on SW.
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #14
    Re: MSW inverter ever ruin any of your appliances?
    waynefromnscanada wrote: »
    That wasn't the case with my two breadmakers. Both had, instead of a transformer to provide the low voltage to logic circuits, a power supply that consisted of a capacitor in series with a resistor, a couple of diodes, one to charge the "filter" capacitor, the other to discharge the AC capacitor on the next negative AC mains cycle, and a zeener diode to hold down and control the DC voltage. Works perfect on SW, but on MSW, all the sharp spikes and sharp corners causes the inline capacitor to "pass" way too much current, very quickly overheating the inline resistor and the zeener diode until the magic smoke comes out and everything stops.
    The Kill-A-Watt has the same style power supply, and to enable it to operate on MSW, the inline resistor has been changed to a much higher wattage rating. Likewise the zeener was upgraded. The first Kill-A-Watt units would burn out on MSW, and since they were so often used with solar systems on MSW, the manufacturer made the changes. But you can within a minute feel the case of the K-A-W getting warm when operating on MSW. It doesn't get warm on SW.
    What brand and Model of MSW Inverter were you using ?? I don't have a breadmaker, But I use my Kill a Watt often on MSW and I'v never had the issues you mention.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #15
    Re: MSW inverter ever ruin any of your appliances?

    I believe the Kill-a-Watt "problem" with MSW was fixed 6-7+ years ago... Anything newer should be fine (a poster called the corp office and was told to look for some Rev Level--But I believe that post disappeared during a major upgrade/conversion many years ago). I could never find it.

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