XW + 6848 Schnieder inverter switching to 40 Hz after generator shut down

ashtonsolarashtonsolar Registered Users Posts: 1
any idea why every time the generator is shut down the inverter only supplies 40 Hz until its disabled and then enabled ?


  • BB.BB. Super Moderators, Administrators Posts: 32,006 admin
    I am not the expert... But the usual first steps are to turn off all power to the system (AC/DC) and reboot after 5 minutes.

    If that does not work, clear the memory/set to factory defaults, reboot, and program (and save if needed) your settings.

    Do you have the current firmware level for your system?

    Hopefully, one of the other posters here that knows 100x more than I can chime in.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • RCinFLARCinFLA Solar Expert Posts: 1,393 ✭✭✭✭
    edited July 26 #3
    I have seen this on several different Xantrex models.  On one of mine if I open the AC input circuit breaker while on grid lock it does this but if I flip breaker off, then on, then off again it disconnects during the re-engagement of breaker and second turn off the inverter does not wander.  Other note worthing item is the AC connect relay does not disengage.

    This make me believe when running locked on AC and AC current is suddenly disconnected the inverter continues to try to stay phase locked to the open AC input.  The AC input relay does not disengage so AC input voltage reading by inverter looks like AC is still there and inverter phase just tracks its own tail.  I think some firmware pushed against the AC input phase slightly to low side to maintain lock causing the condition to wander down in freq.

    Normally when AC grid or generator goes down there is a momentary overload of inverter causing it to disconnect.  If AC path just opens there is no detected current oveload.  Maybe it is not a overload but a certain amount of current increase from the AC input based on max AC current limit settng that cause the disengagement.

    It would seem as soon as the freq wandered outside of allowable inverter set limits it should disconnect.  You might try tightening up the allowed freq range on inverter to see if it improves the disconnect time.
  • Dave AngeliniDave Angelini Solar Expert Posts: 6,028 ✭✭✭✭✭
    The usual cause of Schneider XW+ doing something like this is damage to the AC2 input relay. I would look into the faults and warning history.

     XW+ should go back to 60 HZ within 8 milliseconds.  It should give out warnings that escalate into faults,

    unless XW+ has been damaged. Gensets / Configuration and lack or surge protection are almost always the cause.

    If you really accurately measured 40 Hz, something is wrong as the lowest frequency XW+ can program is 44 Hz. 
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
    E-mail [email protected]

  • RCinFLARCinFLA Solar Expert Posts: 1,393 ✭✭✭✭
    On mine the relay is not the issue.  When grid actually goes down the inverter releases properly.  Only when AC_in circuit breaker is opened does it wander off freq and not immediately open relay.  Have not investigated further since opening AC_in breaker is not a regular use case but I bet if I put some amount of load on AC_in it would immediately disconnect. 
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