\NDAIU>!ZATrO!9 Kt i.t in i / / 11 



and voltage. Th; <*qual 



deducted 



.ind p the percentage of 



at- 



IK/I/: 

 69 Th. VVHIMIMS is I'KIVU M..\, an an* 



ft; engines* is 



c.l in degree*. from the \>< \ould occupy with uniform rota- 



i as 300 degn 



60 -K MOVKKS is the ratio of the difference between 

 the maximum and minimum velocities in an en* -o the average 



61 t in* s A tots or alternating in general 

 it the n lifference in phase of the generated voltage wave from a 

 wave of absolutely constant frequency of the same average value. 

 expressed in electrical decrees (one cycle equals 300 degrees) and may 

 be due to the variation of the prime n, 



62 i :.' ! MOBS or alternating-current n gen- 

 eral, is the ratio of the difference between maximum and minimum fre- 



luring an cn^ he average frequency. 



S3 I- "i VAKIAIIDS in prime mover and alternator. If p-num- 



>f pairs of poles, the variation of an alternator is p times the var 



: direct-connected, and p n times the variation of 



the prime mover if rigidly connected thereto in the velocity ratio ; so that 

 the speed of the alternator is * times that of the prime mo . 



II. PERFORMANCE SPECIFICATIONS AND TESTS. 



TING. 



66 k A us,, m < M MM i. All electrical apparatus should be rated by output 

 and not by input. Generators, transformers, etc.. should be rated by 

 electrical oir ors by mechanical output, and preferably in kilo- 



watts. 



66a The following four classes of rating are recognised and recommended: 

 they do not cover the ratine of railway motors which is treat- 

 Appendix B. and there are other large though less definitely definable rliasei 

 of i which each case must be treated by itself. Some of these 



may be later reduced to fairly simple terms and introduced into these Rules. 



66b i vhich under load there is the attainn 



approximately stationary temperature, and no other limit of capac 

 exce- 



66c '2. INTKRMIM > which one minute periods of load and rest 



alternate until the attainment of approximately stationary temperature 

 and no other limit of capacity is exceeded. 



66d N the temperature depends upon the losses and the capacity 



he appar. it them, a constant load may be sub 



load in determining the temperature, provided the losses are 



m which under load for one minute, no mechanical. 



thermal, magnetic, or electrical limit of capacity is exceeded and no perma- 

 nent wrought in the apparatus. 



66f I \ VKIMMI SKKVICB R\TI i desirable here to recognise this 



class of rating which is intended the rating of motors for machine- 



tool and similar service, in which the thermal absorptive capacity plays a 

 pan. The specif: >r this rating have not been fully determined 



at the time that this edition of the Rales goes to press. 



