It must of taken a while for you to search for that answer, but it still would not explain why the motors don't warm noticeably after being run for a while.

FWIW Denford used a few different versions of Baldor CNC controllers, but something like a Triac would of most likely used Parker stepper drivers, which from what I remember don't have any kind of current reduction. They're either enabled, or disabled, but commercial machines will rarely disable drives, as you run the risk of losing position during disable/enable.