\SUARI>17.A1H>X *r/.A.s < Hit-. .!./ 15 



(F) COMULlAlulc. HklMi ASK 1'Kl %H COSTAO I RESISTANCE t.Qjg 



111 It if desirable to point out that with carbon brushes these loesee may 

 be considerable in low-voltage machines. 



(G) COLLBCt Mm MI - -Off. 



112 .ii is usually negl , m machines of extremely low 

 voltage or in unipolar machines. 



oss, 



113 With separately excited field, the los of power in the resistance of the 



. . alone -. --r shunt- or tenev field 



windings, however, the lots of power in the accompanying rheostat should 

 also be included, the said rheostat being considered as an ossntisl pan 

 of the machine, un<l not as separate auxiliary appara* 



114 (/) LOAD Losses. 



The load losses m. . .tdered as the difference between tl. 



los*< load and the sum of the losses as above specified an 



termined. 

 116 



are and may, therefore, be neglect* r. the 



large as in commutaiing-pole machines; or. as is shown, 

 for he* between no load and 



full 

 considerable, and shi In this case the cm- 



he load losses may l>< the method of Sec. 



116 c the load losses cannot well be 



be considerable and. therefore, their 

 1 by oh - This can be done 



by operating me on short-circuit and at full-load current, that 



is. I called the " short -circuit core loss" With 



the low and great lag of current existing in this cav 



. : : . . .-..:.. ' ...-. ; 



117 core loss may. as an approximation, and 

 in the absence of more accurate information, be assumed as the load loes. 



OF I>If s' OF APfAh 



(A) Pi HI . i <'t K.- 



118 In DIRKI i i'i Kkt M ('OMMI i MIS.. M v le losses are: 



119 : HKAKIM. IK M> WIM>A.I Icasurement of Losses 

 (<* 



120 See 

 Measurement of Losses (/> & 105. 



121 .\KM\II KI. i K LOSSE^ Measurement of Losses (). 



122 d. COMMUTATOR BKLSH FRICTION. See Measurement of Losses (B). 



123 r COMMUTATOR, BlUSfl - IKKMMAMR. See Meas- 

 urement of Losses (F). S< . Ill 



124 /. FIELD Hxcn v See Measurement of Losses (H). Sec. 113. 

 126 t. LOAD LOSSES -n of Losses (/). Sec. 1 



126 NOTE. 6 and care losses in the armature or " armature losses"; 4 and t 

 " commutator losses "; / " field losses/' 



(B) * RENT COM M INKS. 



127 InAi.itKNv s. the losses a: 



128 : Hi \KI-... !'. Measurement of Losses (A). 

 Sec. 



129 6. Ro: ss, measured with the machine at open circuit, the 

 brushes on the commutator, and the field excited by alternating cur- 

 rent when driving the machine by a motor. 



130 This loss includes molecular magnetic fnction and eddy currents, 

 caused by rotation through the magnetic field. / r losses in cross-con- 



