Design, Performance and Application 

 of the Vernier Resolver* 



By G. KRONACHER 



(Manuscript received May 29, 1957) 



The Vernier Resolver is a precision angle transducer which, from the 

 stand-point of performance, resembles a geared up synchro resolver, except 

 that the step-up ratio between the mechanical angle and the electrical signal 

 is obtained electrically. 



Vernier resolvers with step iip ratios of 26, 27, 32 and 33 have been de- 

 signed and built. 



The unit is a reluctance type, variable coupling transformer . By placing 

 all unndings on the stator, sliding contacts are eliminated. Both the stator 

 and the rotor are laminated. Because of the averaging effect inherent in a 

 laminated construction, the accuracy of the unit exceeds by many times the 

 machining accuracy. 



The performance of present experimental units is characterized by a re- 

 peatability of better than ±5 seconds of shaft angle, and a standard devia- 

 tion error over one full revolution of less than 10 seconds of arc. 



I. IXTRODUCTIOX 



The precise measurement of an angle is a basic operation in many 

 technical fields. The observation of stars, mapping of land, machining 

 in the factory are all operations which require angle measurements. Of 

 course, an angle can be measured by reading a calibrated dial. However, 

 in automatically controlled operations the angular position of a shaft 

 has to be sensed electrically. The instrument which performs the con- 

 version from a mechanical angle to an electrical output is called an angle 

 transducer. One commonly used angle transducer is the synchro resolver. 



Basically this is a variable coupling transformer with one primary 

 winding and two output windings displaced 90 degrees from each other. 

 The variable electrical coupling is accomplished by placing the primary 



* The Vernier Resolver was developed under the sponsorship of the Wright 

 Air Development Center. 



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