TRANSDUCERS FOR CONTINUOUS ROTATION 



construction is used in the receiver. However, considerable power may be 

 transmitted if identical units are used at either end of the link; due to the 

 symmetry the power may be transmitted in either direction. 



The terminology of a.c. synchronous links is exceedingly confused, due 

 to differences of nomenclature between Great Britain and the U.S.A., 

 between the Armed Services and between different manufacturers. In the 



Transmitter 



Receiver 



UTh 



Figure 33.30 The M- Motor. A, B and C are ganged switches or 

 cam-operated contacts 



U.S.A. the term 'synchro' covers all sizes of these devices; in addition, 

 nearly every manufacturer has his own trade name (e.g. Selsyn, Autosyn, 

 Diehlsyn, Teletorque, Asynn). In Great Britain it is usual to call low-power 

 units magslips, and large high-power units Selsyns. The details given here 

 will refer primarily to magslips, but will apply approximately to synchros 

 of equivalent size. 



Figure 33.31 A.c. synchronous link — general principle 



With an indicating link, using the special receiver designed for this 

 purpose, the accuracy of the position information is about ±1 degree, 

 but the receiver cannot supply any mechanical output. A large number of 

 receivers may be driven from one transmitter. The accuracy of two similar 

 units used in a synchronous link depends on the mechanical load; on no 

 load ±: 1 degree is possible, while errors of up to 20 degrees will occur if 

 the link is operated at its maximum load. Magslips are made in three sizes: 

 1|, 2 and 3 in. diameter; the corresponding maximum useful torques in a 



497 



