PSN-L Email List Message

Subject: Re: Article on gravimeters
From: ChrisAtUpw@.......
Date: Fri, 12 May 2000 23:05:07 EDT

In a message dated 12/05/00 17:39:45 GMT Daylight Time, 
gjharris@............. writes:

>  You would not believe what the gyros looked like!  Each one was a cylinder 
> about 5 inches in diameter and 8 inches long. The rotor was floated in a can
> in a dense fluid. The pivots were small jewel bearings.

    That sounds about right. And the rotor speed was controlled by two stages 
of centrifugal contacts..... which oscillated and needed precise setting.   
>  The acceleration sensing and precession torquing was done with an item 
> called a microsyn.  It is a small rotary magnetic assembly similar to the
> linear ones in principal.

    My forgettory needs an overhaul ! I just remember selsyns, magsyns, 
magslips, synchro resolvers, twin triodes, vibrating capacitors, chopper 
stabilised amplifiers and then things got hi-tech with Hall Effect 
multipliers. Engineers used slide rules, or math tables, or maybe a Monroe 
Electric Adding Machine. And it took half an hour with a programme on punched 
paper cards to invert an eight by eight matrix, using a computer the size of 
a large living room..... with valves in it.... Gee..... that was long 
ago..... it was another world ! 

    And then Germanium transistors came along.....

    Thanks for reviving the memories.....


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Larry Cochrane <cochrane@..............>