RELAY MEASURING EQUIPMENT 



11 



(luencies is needed. Often impacts and slide of parts must be minimized 

 in order to reduce mechanical wear. Furthermore, the design of high 

 speed relays requires an understanding of how the flux rises and decays 

 when current is connected or disconnected. 



For the experimenter in these fields, many tools are available covering 

 measurements of force, flux, current, and time, or combinations thereof. 

 These measurements may involve shadowgraph, high speed motion 

 picture, or various transducer techniques, and many special methods; 

 some of these are described below. 



The Measurement of Force 



There is a definite need to know how forces in a relay structure vary 

 w ith time. It would, for example, be very useful to measure the force 

 experienced by the relay armature as it presses against its spring load 

 during operation. While a satisfactory measurement technique for this 

 problem has not yet been found, there are a number of similar type meas- 

 urements which can be applied to individual mechanical problems in 

 the structure. For example, with the higher-speed relay functions of 

 today, it is found that relays made by older' methods suffer excessive 



PREAMPLIFIER- 



CONTROL 

 BOX 



■TEST RELAY WITH 

 CRYSTAL INSERTED 

 BETWEEN WEARING 

 SURFACES 



OSCILLOSCOPE 



Barium titanate test set. 



