[TowerTalk] synchro to RS232

[Grant Saviers]

Not sure who was looking for the voltage/current equations for synchros 
but some data is in MIT Rad Lab Vol 25 Chapter 3.  Found by accident.
https://www.jlab.org/ir/MITSeries/V25.PDF

Grant KZ1W

On 11/19/2018 15:28 PM, jimlux wrote:
> On 11/19/18 1:41 PM, Al Kozakiewicz wrote:
>> The defeat of the Nazi's assisted by this analog technology has almost 
>> passed completely from living memory.  Rotary encoders are a fraction 
>> of the price and already signal compatible with digital systems.
>>
>> Or maybe I am missing something?
>>
>> Al
> 
> 
> Synchros (and these days, resolvers) are still widely used as sensors - 
> they're really rugged, inherently a balanced ratiometric device, so wire 
> length isn't a big deal, and its all twisted pairs (or triples) so noise 
> pickup is less of an issue.  They laugh at ESD or transients - it's a 
> transformer - unless the discharge is big enough to destroy the winding, 
> it still works - you can punch holes in the insulation with HV 
> transients all day.  They are also inherently dust/moisture/liquid 
> insensitive - the accuracy is more about the quality of the shaft 
> bearings and how precisely they can locate the rotor within the stator 
> windings.
> 
> You can easily transformer isolate them for galvanic isolation (a real 
> issue with long sensor wire runs - galvanic isolation is good)
> 
> Unlike a quadrature encoder, they're an absolute position sensor - no 
> need to "find home" and count pulses.   Yes, there are absolute rotary 
> encoders, but they don't have 16 bit accuracy, without a geared scheme 
> and two encoders.   16bit accuracy is achievable off the shelf with a 
> resolver at moderate cost (a few kilobucks, brand new, for resolver+chip 
> to turn it into a digital number).
> 
> You'll also see the linear equivalent called a LVDT (Linear Variable 
> Differential Transformer)- same basic idea, a transformer made with a 
> stator with multiple windings, and  a slider that has an excitation 
> winding.  Used in the same sort of hostile industrial environments.  You 
> don't need three phases (or quadrature) for an LVDT, because the motion 
> is constrained - no need for "unwrapping"
> 
> 
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