Transfer times and synchronization

interd0ginterd0g Registered Users Posts: 7
I have a nice SW4024 system which has been up for about 15 years and works very well.We since got shore power, but i just kept that for supplementing the power occasionally like an auxiliary generator. There are many power cuts here (Antigua) but we wouldn't know as the 4024 takes over seamlessly.
This brings me to the question. The 4024 had a unique configuration where it synchronized with the incoming source ( gen/utility) and when syncd, connected both source and inverter to the load with load sharing and charge management.
I liked this because the seamless syncd transfer was very kind to the electronics in the house.
A PC or audio/video system would show zero symptoms iof a transfer.
Whereas the usual relay transfer ( say 10-15 mS) with no sync gives you

1) A short interruption to the sine wave with spikes
2) Resuming power with a sharp phase shift.

The equipment hiccups and you can feel the pain, even though it may not crash.
I know this is bad for the life expectancy of all the stuff.
Anyone know of a currently available inverter that works like the SW4024 with the synchronization?


  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Transfer times and synchronization

    Well I've not seen an inverter that produces the problems you mention when shifting from battery to AC IN but there's no doubt plenty of cheap ones out there that do.

    The real feature you're talking about is load sharing, where an underpowered generator can be used because the inverter will pull from the batteries and boost AC output capacity if any heavy loads come on. Pretty sure the Xantex XW line still is able to do this. It can be a bonus if you're needing to run a small, fuel-saving generator but also have the possibility of a sudden heavy load like a water pump coming on automatically.
  • RCinFLARCinFLA Solar Expert Posts: 1,453 ✭✭✭✭
    Re: Transfer times and synchronization

    Most inverters, even Modifed sinewave inverters like old Trace DR series, that have immediate switchover have syncronization between AC main in an the phase of inverter. You cannot do an immediate switchover if there is not syncronization as it will drive a motor crazy, causing a very high surge current.

    Only a sinewave model can run in parallel with AC main in, like SW series.

    The Xantrex XW series and Outback inverters do the same thing as the older SW inverter.

    Most transfers are less then a cycle but worse case it can be up to two cycles of dropout. If you set inverter mode so it is normally in standby (inverter not actually running) then there is some extra cycles while the inverter become active after an ACin power failure.

    Most computer power supplies can handle a couple of cycles dropout but four or five cycles are likely going to cause a reset of computer.
  • RandomJoeRandomJoe Solar Expert Posts: 472 ✭✭✭
    Re: Transfer times and synchronization

    My Outback VFX-3648 switches between line and inverter quite regularly. I take advantage of the solar power whenever possible, but don't want to draw the bank down nightly as far as 24x7 operation would do - plus of course power failures. The inverter is off when using grid power.

    In the hundreds (thousands?) of switches it has done, whether commanded or through grid failure, I have never had any of my attached equipment - primarily several computers and the refrigerator - even indicate they noticed the switch, let alone reset / reboot.

    The only time I have ever been able to tell is when I have a desk lamp turned on. There is *occasionally* the very briefest and faintest of flickers at the time of switchover. Most times that doesn't even happen!

    Now, the one feature that I'd LOVE to have is load-sharing. This one doesn't do that. That would be sweet! :)
  • RCinFLARCinFLA Solar Expert Posts: 1,453 ✭✭✭✭
    Re: Transfer times and synchronization

    Was not aware that Outback did not do load shaving. No technical reason I can think of why it shouldn't. Probably a patent thing. The GFX don't like gen's period because of tighter lock frequency requirements.

    The SW's and XW's can. When I run my 'tickle' charger, a Yamaha EF3000sei, I set the max AC2in from isolation/120v to 240v transformer to 10 amps. If ACout loads are are greater then 10 amps the inverter suppliments from batteries. When ACout loads are less then 10 amps then difference is used to charge batteries.
Sign In or Register to comment.