MotionMaster Upgrade

Hey, you are spot on. I realized this late last night as well. The manuals confirm that this series of drives are designed for 120V inputs.I also confirmed that the power supply going to the chassis is a 277V (single leg of 480-3) so it must be that there is a voltage drop, and then, a rectifier before the capacitor. I attached the picture for today's work, but I think there is an SCR directly below the cap, and to its right is the rectifier. I was expecting a transformer and completely missed the SCR hidden behind the wires. I'm trying not to change the wire layout until I am more comfortable, but I think I am getting there. 

So I think the drives have: DC in, DC out, tach, reset/enable and 10V command. 

I do not believe there is a bridge rectifier. I think its just an SCR and then a couple of diodes. Will take apart the wires and check today but I am getting more and more confident that if I identify the 120V input (native to the SD chassis, without the 480V single leg add on) I should be able to connect 120V to it and make it work. Just need to find me a box of 100W lightbulbs.