RELAY MEASLRIxXG EQUIPMENT 



STRAIN GAUGE 



CURRENT SUPPLY 

 CABINET 



Fig. 1 — Tensile testing machine for force-displacement measurements. 



of operation of this machine will be given only in outline as it is described 

 elsewhere. The force system to be measured, such as a relay magnet, 

 is mounted on the crosshead of the machine, whose motion up or down 

 may be controlled from the panel on the right. The other side of the force 

 system being measured is comiected to a strain gauge fastened to the; top 

 framework of the machine, and as the force on the strain gauge progres- 

 sively changes, an electrical indication is given to the pen of the Leeds 

 and Northrup X-Y recorder which then moves horizontally in proportion 



