Xantrex sw5548 gen sync error

johnmau

Have a two 2007 Xantrex model sw5548 that are stacked and have been hooked up for several years working fine. Off grid system in Texas. Have a large batt bank and a 2017 Kohler 30kw gen that comes on and off automatically. All has worked fine for quite awhile ( 600 hrs on gen). Today I manually turned the gen on and both inverters sync’d fine. About 30 min later some lights flickered in house so I went to investigate. Master inverter had lost sync and was attempting to re attempt bit could not. Inverter somewhat got lost and was somewhat surging and lights were flashing. Shit it down so it would do more damage. Had a gen sync error. Haven’t had that before. Had to hard shut it off to get it to quit. Turned back on and inverted fine. Checked gen. Volts and freq good. Checked every setting I could and all good. We lowered the charger amps thinking we were messing with it’s brain at a max setting but still did it. Thinking we have a relay R7 or R8 that might be weak? Any thoughts would be appreciated. Thx
John

Cutterzoo

Posted almost the same exact problem two days before you.
https://forum.solar-electric.com/discussion/356299/trace-5548-in-series-kicks-out-generator#latest
I don't currently have a meter capable of measuring frequency, so have not been able to determine that, but based on my other troubleshooting, doesn't seem likely.

Please hit my post if you find a resolution, and I'll do the same.

- Mike

mcgivor

Could be the contacts of the transfer relay are becoming high resistance due to arc induced pitting, if access to them is possible they could be dressed with 320 grit wet/dry paper or emery cloth. This is common for relay contacts that have been in service for extended periods, often resulting in the contacts becoming welded due to the heat buildup.