I 'inherited' a 3phase 15KW generator without documentation or even a brand
name on it. It works well enough but I don't understand some of the
switches on its front panel. Perhaps somebody more into generators then I
am can explain them?

Except for the start/stop switch (I do understand that one) there are two
other switches, marked with the following positions:

switch 1 :
L1L2
L2L3
L1L2 -- set on this position
OFF
L1-N
L2-N
L3-N

switch 2:
OFF
L1 -- set on this position
L2

What function do these switches have? Is it safe to 'try out' the other
settings?

TIA

Jor