GRAPHIC RECORDING INSTRUMENTS 561 



frequency, and power factor. Special types have been developed 

 for use in tests of electric cars and locomotives. 



In selecting curve-drawing instruments it should be kept in 

 mind that in many of those on the market the inertia of the 

 moving parts is so great that rapidly varying phenomena will 

 not be correctly depicted. 



References 



"Graphic Recording Meters," Electric Journal, vol. 3, 1906, p. 296. 



"Investigating Manufacturing Operations with Graphic Meters," C. W. 

 DRAKE, Electric Journal, vol. 7, 1910, p. 536. 



''A Graphic Recording-Ammeter," A. H. Armstrong, Trans. American 

 Institute of Electrical Engineers, Vol. 22, 1903, page 689. 



36 



