I have a 50hp Louis Allis shunt wound DC motor circa 1970's/ early 80's, controlled by a newer bardac DC drive. Originally was controlled by a louis allis drive. What puzzles me is in the drive cabinet, they have 2 giant contactors (each about the size of a cinder block) for switching the armature wire for direction control. I am puzzled as to why they would not just use a couple of multipurpose relays and switch the field wires.
In a stranger note; one of the contactors quit working & I had to run the machine backwards before it was mechanically safe to turn off the machine to do electrical work, so I swapped the field wires and tried to run it. All that happened was I blew a couple of 100A fuses (likely due to a seperate issue - water in a junction box between the drive cabinet & motor).
I thought that sawpping either the field OR armature wires would change direction; am I wrong?
In a stranger note; one of the contactors quit working & I had to run the machine backwards before it was mechanically safe to turn off the machine to do electrical work, so I swapped the field wires and tried to run it. All that happened was I blew a couple of 100A fuses (likely due to a seperate issue - water in a junction box between the drive cabinet & motor).
I thought that sawpping either the field OR armature wires would change direction; am I wrong?