STANDARi S Of THh. A I i i: 



161 . A KM M t RE-RESISTANCE Lota. See Measurement of Lossn (). Sec. 



162 d COLLECTOR K ts<> BRUSSJ l 



163 M TO*. RING BRI- 



164 . Lots. Sec Measurement of Lossss (10. Sec. m 

 166 t L04 r Measurement of Losses (/). Sec. Ill 



(fi) ?t nfcTioN APPARATUS. 



166 I- >s APPARATUS the losses are: 



167 measured at 

 open second.* l, rated frequency, and at rated voltage / r. where 



' - resistance of primar 



168 LOSSES, the sum of the /' r losses in the primary and 

 in the M-vondary windings of a transformer, or in the two sections of the 



isator or auto-transformer, where /-rated current in 

 the coil or section of coil, and r resistance. 



169 i LOSSES, i.r, eddy currents in the iron and especially in the 

 ;-er conductors, caused by the current at rated load. For practical 



purposes they may be determined by uting the secondary of 



the transformer a; ssing upon the primary a voltage sufficient to 



send rated load current through the transformer. The loss in the trans- 

 these conditions, measured by wattmeter, gives the load 

 losses + 7*r losses in .ary and secondary coils. 



160 In CLOSED ' in TRANSFORMERS, either of the two circuits 

 may be used as primary when determining the efficiency. 



161 > should be taken at the max- 

 imum voltage for which the apparatus is designed, and with non-ind 

 load, unless otherwise specified. 



ROTAR\ >s APPARATUS, or INDUCTION ' ' \- MINES 



162 In ROTARY IMKTIION .\IT\K MIS. the losses are: 



163 a. BEARING FRI .K. See Measurement of Losses (A). 

 Sec. 



164 b. Mi.- FKICIIOV n iron, copper 

 and other metallic parts; also I- r losses which may exist in multiple- 



ngs. a and 6 together are determined by running the motor 

 without load at rated voltage, and measuring the power input. 

 166 t. PRIMARY 7* R Loss, which may be determined by measurement of 

 the current and the resist. i 



166 d. SECOMAK\ /* K Loss, which may be determined as in the primary, 

 when feasible; otherwise, as in squirrel-cage secondaries, this loss is meas- 

 ured as part of t. 



167 f LOAD LOSSES; i.r. molecular magnetic friction, and eddy currents 



ron, copper, etc.. caused by the stray field of primary and secondary 

 currents, and secondary / R loss when undeterminable under (4). These 

 losses may for practical purposes be determined by measuring the total 

 power, with the rotor she: 1 at standstill and a current in the 



primary circuit equal to the primary energy current at full load. The 

 loss in the motor under these conditions may be assumed 'to be equal to 

 the load losses + P r losses in both primary and secondary coils. 



(G) \R OR A NES. 



168 In UNIPOLAR MAC MINES, the losses are: 



169 (a) BEARING FRICTION AM> WIM.\..K See Measurement of Losaci 

 (A). S< 



170 MAGNETIC PRKU -s ^ CURRENTS. See 

 Measurement of Losese (/ <>d. 



171 u i ARMATURE-RESISTANCE LOSSES. See Measurement of Losese (). 

 Sec. 



172 (d) COLLECTOR -BRUSH FRICTION. See Measurement of Losssi (Q. 

 Sec. nn 



