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..

does this unit have a generator?

There is not a generator. The disconnect is the only updated equipment in the machine room. 3 phase 40 amp and the legs are reading good.

3 phase transformer output is good.
rectifier output is good.
door contactors work manually.
The last point of power is at the bottom of the 3 pole C contactor. Honestly I'm not sure if that should be AC or DC . I get readings of both. If its AC then the third leg is down at the contactor .

Pictures Transformer, Rectifier, C contactor

I think on the old Otis stuff the C contactor was the safety string contactor, it pulls in when your safety string is made. Sounds like your safety string is open somewhere. I'm not sure if I have anything from the 50s to get prints from. The couple older Otis's I have I believe are the 60s and one from the 1920s with a brass hand switch in the car

The Otis 1957 is back alive. Schematics even though poor quality were the key here. There was a lot going on.

Parts Im having trouble with is the Overload dashpot relay N301. They are in series with each other. Relay labeled #1 tripped when swapped in the controller. Not the best idea but I jumped it out and the unit took a call.

The door circuit isn't working because "NT- hall timer sw." wont pick . Receives 135v DC at the coil, while getting voltage I manually engage it and the door circuit works fine.

ultimately I need relay dashpot oil ( the #1 overload was lower on oil than the #2.) or a new N301
and a replacement coil for NT switch
Then some tuning. The last certificate is from '97. The owner wants this inspected.

Does anyone know where to get new rixson door closers? The ones in the floor ?

Not to sure what you are referring to. I have not encountered one. Is this for an older OTIS.
Post a picture I would be curious to see it.
Unfortunatley you may need to upgrade( did you check unitec), or rebuild it.

Im curious how mechanics set up a temp run button back in the day?
any substitute with todays oils that would be equivalent to 50's dash pot oil?

I’m working on one of these now. Type looks like 10NOB. Could you share your print ? And the door closers are shot. They are rixson #25. Old style LH bottom door check . Can’t find them

Pivots & Pivot Hinge Door Hardware Sets - RIXSON https://www.rixson.com › products › pivots-and-pivot-s...

Txs. I was told they were out of business

Does anyone have a print for any type of 10N1P? I have a 4 stop residential with no print. Wiring Diagram is 2SF6880-A, does anyone have a print that is remotely similar to that diagram? I know I have a problem in my safety circuit however, I was born in '86 so this is a little before me. Thank you!

C relay is the safety circuit.. Does the coil have voltage across the coil leads. Dashpot fluid for the overloads is available from Allen-Bradley.

Did you ever find a print?

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