Recently came across these two Otis units . Its been tricky working on these chasing wires.

The '51 is back in service and runs very good, it is in a residence, 3 stop. I have been able to study this one and compare to the other. Seems the transformer and rectifier have been updated.
1951 type:10N1P wire diagram: 2S6880A Machine Type: 35ES

The '57 is very similar but several more relay contactors, Just 2 stop. This one is not running yet, but its getting close. Original everything except maybe a capacitor on the back.
1957 type:10N1T wire diagram:13-1S6878 A Machine type:49ES
The good
-The phase monitor engages. transformer output is at 100v on each pole, the rectifier had output of 135v DC, Door Open and Door Close contacts work when manually pushed

Not good
-"C" contact wont make, but it has DC- 60, 60 , 130 across the bottom of the contactor. Even if I manually engage the "C" contactor nothing else reacts.
-The unit is between floors at the moment.
At a point of needing some type of wiring Diagrams or any input from the old school Techs
pictures coming..