Inverter..with or without transformer

System
System Posts: 2,511 admin
in Solar Beginners Corner #1
Can anyone indicate me a website or source that lists the plus points of having a solar inverter WITH a transformer as opposed to transformerless please?
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  • john p
    john p Solar Expert Posts: 814 ✭✭✭
    #2
    Re: Inverter..with or without transformer

    never heard of an inverter without a transformer.. and cant possibly see how it could ever be made. what is going to step up the voltage if not a transformer??magic candles?:confused:
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  • System2
    System2 Posts: 6,290 admin
    #3
    Re: Inverter..with or without transformer

    Transformerless inverters are commonly sold here in Europe and very often tender documentation specifically requests such inverters. Thats why im doing this research.
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #4
    Re: Inverter..with or without transformer
    john p wrote: »
    never heard of an inverter without a transformer.. and cant possibly see how it could ever be made. what is going to step up the voltage if not a transformer??magic candles?:confused:

    Magic FET's Lots of them

    DC motor driven - AC generator ?

    OMG !!

    http://w1.siemens.com/press/en/pressrelease/?press=/en/pressrelease/2009/industry_automation/iia2009051934.htm
    http://www.solarfeeds.com/ggs/6740-transformerless-grid-tie-inverters-lower-cost.html

    It must be witchcraft!

    NO , they CHEAT, and rely on the building's transformer:
    http://www.pvworld.com/index/articles/display/0777426156/s-articles/s-Photovoltaics-World/s-volume-2009/s-issue-30/s-features/s-transformerless-inverters.html
    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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  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    #5
    Re: Inverter..with or without transformer

    AFAIK, some countries like the UK don't allow transformless inverters yet because of the lack of isolation. There are some grounding issues too - some thin film panels must be used with transformer inverters. Recommend you call someone like SMA and find out the pro's and con's of each.
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  • RCinFLA
    RCinFLA Solar Expert Posts: 1,485 ✭✭✭✭
    #6
    Re: Inverter..with or without transformer

    I think you are referring to 60 Hz isolation transformer.

    Most low cost inverter have a high frequency boost circuit to take the battery voltage up to 155vdc for modified sinewave or 190 vdc for sinewave inverters. The boost circuit has a small high frequency ferrite transformer.

    This high voltage D.C. is then chopped to produce the A.C. output through an H-bridge MOSFET output driver.

    These type of inverters can not be neutral side of A.C. plug (the wider blade prong) grounded (bonded) to a house electrical box, without adding an external isolation transformer.

    Also, inverter-generators less then 3kW also have the same H-bridge MOSFET circuitry and have the same issue of non-groundable neutral.
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  • john p
    john p Solar Expert Posts: 814 ✭✭✭
    #7
    Re: Inverter..with or without transformer

    I kinda think Ishould have read the OPa little bit better before saying anything.. I was only thinking he was asking about the usual sinewave /modified sinewave 12v /24v dc to 120/240 v ac inverters..:grr
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #8
    Re: Inverter..with or without transformer
    Maltaman wrote: »
    Can anyone indicate me a website or source that lists the plus points of having a solar inverter WITH a transformer as opposed to transformerless please?

    Solar Guppy mentioned it in http://forum.solar-electric.com/showthread.php?t=5694 post #5
    galvanic isolation I guess it's required in most places in UK & USA
    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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  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    #9
    Re: Inverter..with or without transformer

    Just comparing the SMA kit, the transformless inverters offer:
    - Slightly higher efficiency
    - Slightly wider MPPT range
    - Less weight :D
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  • System2
    System2 Posts: 6,290 admin
    #10
    Re: Inverter..with or without transformer

    Thanks for that...my main interest is in what the ADVANTAGES are of inverters that HAVE a transformer compared to transformerless...
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  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    #11
    Re: Inverter..with or without transformer
    Maltaman wrote: »
    Thanks for that...my main interest is in what the ADVANTAGES are of inverters that HAVE a transformer compared to transformerless...

    A fault in the inverter electronics can not backfeed 240 VAC into the solar array when there is a transformer, its a major safety advantage
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  • boB
    boB Solar Expert Posts: 1,032 ✭✭✭✭
    #12
    Re: Inverter..with or without transformer

    Ideally, a transformer-less inverter should have some way of disconnecting the AC from the inverter in case of a fault. Either a relay or triac or SCRs or something like that.

    boB
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