Marine Gyrosphere motor specs ? Sperry Litton

[oz2cpu]

Hello
I scored such a unit, and i have trouble finding motor specs,
motors are 3 phase induction, with a capacitor so they run on one phase AC
please tell me : AC Voltage, Frequency, expected current,
RPM ?

other things i like to know if you are an expert with in this field :
how could it Loose its liquid mercury ?
is there any special kind of gas inside the motor sphere ?

I put all details about my unit in this video
https://youtu.be/10hITIeLjIU

[SeanB]

Very likely either 115VAC 400Hz, or 26VAC 400Hz, and the original fill of that housing would have been a blend of ethanol and mineral oil, not water, as that provides the needed damping, and also lubrication. The mercury wetted contacts are very interesting, likely they are steel with a copper or silver plating on them, thus the mercury contamination. The 0.33uF says 400 or 440Hz, so probably try that, and what was original excitation voltage off the amplifier.

[oz2cpu]

thank sean for the feedback,
as shown in the video i already tried with 400Hz +/- a lot
searching for a peak acceleration, that just dont reveal it self what so ever sadly..
it is not like i am a lost case, my power stage works and drives avionic equipment fine,
maybe you have seen my other gyro worked fine with 115V 400Hz,

[moffy]

They should not be making that grinding noise, they are meant for high RPM because of their small size, like 12000 RPM, or some multiple of the 400Hz, maybe a bad bearing?

[Doctorandus_P]

400Hz is already 24000rpm 

[moffy]

400Hz is already 24000rpm 

True enough, but it does depend on the number of poles e.g. 4 poles@400Hz = 12000 RPM 
https://en.wikipedia.org/wiki/Synchronous_motor
but not necessarily a multiple of 400.