ANALYSIS OF PULL AND MAGXETIZATIOX MKASIHIOM KNTS 



SO 



\'alu('s of ,r incasiu'cd from this oi'i«iiii arc Icnin'il I raxcl, as disl inmiislicd 

 from gap ^■alues, which are measured from I he position of iioii to iron 

 contact. 



If the relation between (sV (x) and .r confoi-ms to (ii), the \ahie.s of 

 P(.v) must conform to: 



Pix) = i-+ .^^. .. • (8) 



(Ri 



A6\o + X 



Tlien if .r,- is a c(Mitral reference \ahie of .r, and /'(Xr) the corresponding 

 value of P(x), the expression for J\xr) — P{.i') given by (8) may he 

 written in the form: 



X — Xc 



Xc 



A 



= -1 UHo + -^^ + (Ro + ^ (x - xc) 



A 



(9) 



P{xc) - P{x) 



Thus conformity with (3) re(iuires the ratio given by (9) to vary 

 linearly with x. This ratio is plotted against x — Xc in Fig. 7, referred to 

 the upper and right hand scales. The values of this ratio are sensitive to 

 deviations in the values of x and P(x) near Xc , and minor variations 

 from linearit\' are to be expected here. Allowing for this, the results 

 agree with (9), and the relation between (ft' (x) and x therefore conforms 

 to (3). 



From (9), the slope and intercept of the linear plot may be interpreted 

 as indicated in Fig. 7. Then A may be evaluated by dividing the intercept 



-Is 

 II 



Q. 



0.02 0.04 0.06 0.08 O.IO 0.12 0.14 



TRAVEL, X, IN CENTIMETERS 



Fig. 7 — Evaluation of equivalent circuit constants. 



