What is off-loading tap changer?

Off-load tap changer works on the principle “Break before Make” which breaks the current flow and makes the new tap connection. So this tap changer works when there is no current flow in the transformer windings i.e. it cannot work even when the transformer is energized because it can break the magnetizing current. It is nowadays called as De-energizing tap changer instead of No-load or Off-load tap changer.