Here is a query that will show you the time between log switches. It can be handy in determining if you have a problem:

select b.recid,
to_char(b.first_time,'dd-mon-yy hh:mi:ss') start_time, a.recid,
to_char(a.first_time,'dd-mon-yy hh:mi:ss') end_time,
round(((a.first_time-b.first_time)*25)*60,2) minutes
from v$log_history a, v$log_history b
where a.recid = b.recid+1
order by a.first_time asc
/