150w Sylvania Lumalux S55 lit on Euro gear.

1 x US 150w 55v lamp lit on "240v".

I used a 400w MBF choke and used a variac to lower the input voltage to maintain a 3.2 amp arc current.
Seemed happy enough but the arc voltage only seemed to want to come up to about 48v.

I used a standard superimposed ignitor which was then removed from circuit when the lamp struck.