The Low Voltage Incandescent Lamps "May" run a little better using DC instead of AC (well filtered DC as opposed to AC), but the most apparent reason would be to drive LED type Lamp arrays.

Wish I had a definite answer for you, but not knowing the specifics per installation / usage / equipment types, I can only "Ass-U-Me" these two things!

[Linked Image] on the 'Ass-U-Me" word usage!!!

Scott35

Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!