STANDAR/>IZAT/o.\ jfr/.A.s oh iin A I E.E. 13 



BFPIC1 



(I) DEFINITIONS. 



4 an appat output to iu input 



The output and input may .r m term* of watt-boor*, wmtu. volt-ampere*. 

 ampere*, or any > of interest, thus respectively defining 



energy-enVim. -.. 5.. A,-: r!i. ,!.-.. . 4 ;. ;.,-- ,-! , : ......... 



AIM specified, however, the term it ordinarily 



i :.,: : - " -. -.. . - 



66 An In Apparatus in which a . 



inh< -i. apparent enVirnt-y should be 



the ratio of net i ,\\. 



87 .. .oton. synchronous 



phase modifiers, >ous converters controlling the voltage of an 



alte: d regulator*, open magnetic circuit 



Iran 



86 parent efficiency of apparatus delivering electric 



pou the load, the apparent emciency. 



unless otherwise specified, should be referred to a load power-f actor of unity 



MEASUREMENT Oh Eh'hK 



89 :nay be determined by cither of two methods, 

 vts.: by measurement of input and outp -nent of losses. 



90 I The input and output may both 

 be meas !>. The ratio of the latter to th- the emciency. 



91 .' SES. The losses may be measured either colic 



1 losses may be added to the output to derive 

 nput. or subtracted from the input to derive the output. 



92 COMPARISON The output and input method is preferable 



. small machines. When, howevi r. as in the case of large machines, 

 measure the output and input; or when the per- 

 'age of power loss is small and the emciency is nearly unity, the method 

 of determining rtVu u-ncy bv measuring the losses should be followed. 



93 i hould be measured at the terminals of the appar- 

 atus. In te .phase m.. he measurement of power should 

 not IK* a single circuit but should be extended to all the cir- 

 cuits in ord< : 1 errors of unbalanced loading. 



N POWER in machines should be measured at the pulley, 



gearing, cout thus excluding the loss of power in said pulley, 



gearing or coupling. t> ng the bearing friction and windage. The 



magnitude of bearing friction and windage may be considered, with con- 

 stant speed, as independent of the load. The loss of power in the belt and 

 the increase of ! -n should be excluded. 



is mounted upon the shaft of a prime n 



iot be separated therefrom, the fractional 



losses in bearings and in windage, which ought, by <: to be included 



y. should be excluded, owing to the practical 

 impossibility of separating them from those of the prime mover. 



96 In A APPARATUS, such as an exciter, the power lost in the 



auxiliary apparatus should not be charged to the principal machine, but 

 to the plan* ng of principal machine and auxiliary app.t 



taken together. The plant emciency in such cases should be distinguished 

 from the machine efficiency. 



96 . tests should be made under normal 

 conditions herein set forth, which are to be assumed as standard. 

 These conditions include voltage, current, power-factor, frequency, wave 

 shape, speed, temperature and barometric pressure, or such of th< 

 may apply in each particular case. Performance tests should be made 

 under these standard conditions unless otherwise specified. See Sees. 



75. 



97 a. TEMPERATURE. The efficiency of all apparatus, except such as may 

 be intended for intermittent service should be either measured at. or re- 



