Seamlessness passes

interd0g
interd0g Registered Users Posts: 7
Sooner or later my 12 year old SW4024 will pass on and I will have to replace it. A great feature of this one was the seamless transfer which they got by synchronising the inverter with the source (genset or utility). Without this feature you notice some acute discomfort from your household electronics when the xover takes place due to the 6 -20 mS transfer gap plus resuming power in a random other phase condition.
Stuff may reset or worse. TVs bloom and splutter.
I know my stuff hates that, and I'm sure it stresses it out.
As far as i read it the XW which seems to be the nearest to the SW now available, has a traditional non-sync big-bang xover.
Anyone have a view on this problem?

Comments

  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    Re: Seamlessness passes

    XW is exactly the same this way, out of the box running if AC1 or AC2 fails it does an automatic transfer in milliseconds.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Seamlessness passes

    Outbacks are 'seamless' too. The switch-over is programmable for cycles and length. I've only ever noticed a 'blip' when the generator was put under a sudden, heavy load and its voltage dropped. This causes a momentary system-wide voltage drop before the inverter can switch back.

    Are there any generator-tied inverters that don't switch 'seamlessly'? It would be silly to make one so.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Seamlessness passes

    My two cents worth of warning from working with medium sized UPS's connected to arrays of "desktop" type PC's and other computer systems.

    The UPS's with invert on failure switch over--they usually advertise a 16 milli-second (or less) fail-over switching... And every lab test I could perform (including those with equipment that could be programmed for x cycles of voltage drop)--they worked great. Computers would stay up and nothing would hiccup.

    However, in real life--it would seem about 10% of the real world power failures on good quality UPS's and Computers would cause a power failure crash on the computers--I could never reproduce the failures in the lab (real world dirty power during failures confuse UPS power fail detectors? :confused: ).

    So, if you have critical power needs (i.e., desktop computer working with your company finances) you should have a small continuous conversion UPS just for the PC (and it will be a power hog--I am sure). As well as a good backup system for your data (backup as often as you need -- when the time to reproduce the lost data is worth more than the backup system costs).

    Otherwise, I really like laptop computers for use in "dirty power" systems as they are low power usage (great for solar RE) and already contain their own (internal) continuous conversion UPS (their battery pack).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • interd0g
    interd0g Registered Users Posts: 7
    Re: Seamlessness passes

    BB, my experience has been the same. Relay transfers in 6 -20 mS don't really do it, and how do you think your kit feels when its restarts in a new random phase condition? It feels lousy.
    Designers of domestic stuff are not required to design in provisions for liking wierd waveforms or unusual glithes in the supply. Only on-line ups's would be OK.
    The SW was really good for this. E.G. we used it on some megayacht installations where the bridge electronics couldn't stand it when switching between generators/shore power etc.
    You can visualize the situation on a bridge full of stuff when it resets as they enter port in a fog.
    Before I had the SW, I built in a minimum 3 minute transfer!
    That way you do a normal shut down and normal power-up on all your reefers and electronics, which is kinder than a mega-glitch.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Seamlessness passes

    transfers in the 6-20ms range are nothing to slouch at. when needing better and there's no transfer figures out there that suit, then i think having said equipment run by the ups or inverter all of the time is the alternative. in way there really isn't any transfer or transfer time to really speak of. not very efficient that way though.