Roto Phase Convertor

Newcomer to the site
Dealing with a 3 phase convertor powering a 15hp 38amp 60hrtz motor.
Fed by single phase 250 volt incoming.
Powering up the converter I get readings of 125V on lines 1&2 and a reading of 275v on the ghost line.
Any idea why the ghost line would be that high. It was created using 7 capacitors @ 60 mcfds.
This is an old convertor built back in the 80's or 90's
Really didn't change any wiring in the convertor, just the feed line.
Any guidance would be appreciated