I don't know the Why?<br>
I thought maybe you wanted general ideas "Sorry"<br>
I've heard there is a company in California that builds a kit add-on for your exicter problem , don't know if it works<br>
or not,or the name of the company.<br>
The system's I've worked on gen,ups,& harmonic trouble.<br>
Independent Ups. 120v models seem to be the worst, multiple units on the same phase."Again I don't why" they multpiply <br>
the hormonic on the system causing exicter burnout,I've seen<br>
the Ups's melt each other under these conditions.<br>
I was able to fix this with transformers,208/240v Ups,change<br>
the grounding between systems utility,gen,ups.The required<br>
grounding under local and national electrical code "us" does nothing but make harmonics grow and move!<br>