RCA 900491-502?

I have what I think is a RCA transformer with the number 900481-502. It has four leads. I have been scouring the old literature to possibly run the part number somewhere but I can't not find it. Does anyone know anything about this baby?

491 is a power transformer with more than 4 leads.  No idea what 481 is. 

DC resistances? 

1.1 ohms for one winding.  13.5 for the other. 
large tran.  3.25 inches tall.  2.5 inches diameter.

That would probably be a filament transformer of some sort.  110-115VAC on the higher side. 

Ok, thanks

On a slightly different subject, I bought some Collins transformers that I did not realize came from an aircraft servo amplifier.  One of the transformers  is a 400hz power transformer(115v to 6.3v), the other transformer is an audio input transformer which appears to be 1k:100k.  A possibly dubious spec sheet I found for it states the turns ratio is 1:20.

Firstly, does anyone know what a servo amplifier is? Possibly this a servo for controlling an aileron  perhaps...etc.

Secondly, does a servo amplifier truly use an audio transformer, and if so, can I use it for something?