STANDAKDIZATJO19 RULES OP Tilt. A I KB. 



307 I'kiuAKv IIM In Alternating-current. 



I, Bfiflsfjry*diitnbui u. an average voltage of 2.200 volts. 



with step-down transformer ratios I/ 10 and 1/30. is in general use. and U 

 ftOOOUBMdtd* 



308 TRANSMISSION alternating -current constant -potential 



:i emission 4get are recommended. 



,60' (100 33.000 44.000 ttA.OOOHM.000 110.000 



109 i ORMRR K commended that the standard transformer 



should be such as to transform between the standard voltage* above 



named. usually be an exact multiple of 6 or 



310 KAM.I \'.i In alter nat 



systems, a range of terminal voltage should be provided from rated voltage 

 at no load to 10 per < p in transmission. 



If a greater range than ten per cent is specified, the generator should be 

 considered as special. 



H FRKQUENCi 



311 In ALTERNATING-CURRKS ITS. the* following frequencies are. 

 standar 



25 cycles 60 cycles 



312 These frequencies are already in extensive use and it U deemed ad- 

 visable to adhere to them as closely as possible. 



IV. GENERAL RECOMMENDATIONS. 



313 NAME PLATES.* All electrical apparatus should be provide*! with a name 

 plate giving the manufacturers' name, the voltage and the current in 

 amperes for which it is designed. Where practical) watt capacity, 

 character of current, speed, frequency, type, designation and serial num- 

 ber should be added. 



314 DIAGRAMS OP Coxst All electrical apparatus when leaving the 

 factory should be accompanied by a diagram showing the electrical con- 

 nections and the relation of the different parts in sufficient detail to give 

 the necessary information for proper installation. 



316 RHEOS rheostat should be clearly and permam 



marked with the voltage and amperes, or range of amperes, for which 

 15 design- 



316 COLORED I .in-. When using colored indicating lights 

 on switch-boards, red should denote danger such as " switch closed." 

 or "; green should denote safety, such as " switch open." 



circuit ii 



317 When white lights are used a lig^ht turned on should denote danger, 

 such as " switch closed " or " circuit alive "; while the light out should 

 denote safety, such as " switch open." or Low-effi- 

 ciency lamps should be used on account of their lesser liability to acci- 

 dental burn 



318 The use of colored lights is recommended, as safer than white lights. 



319 GROUNUING METAL WORK. It is desirable that all metal work near 

 high potcnti.. be grounded. 



320 .DEVICES. The following definitions are recommended. 



321 KEAEER is an apparatus lor breaking a circuit at the 

 highest current which n may be called upon to carry. 



322 h. AIM-.. s an apparatus designed to open a circuit 

 only when carrying little or no cur: 



323 c. An AUTOMATIC CIRCUIT- BREAKER is an apparatus for breaking .. 



automatically under an excessive strength of current. It should be 

 capable of breaking the circuit repeatedly at rated voltage and at the 

 maximum current which it may be called upon to carry. 



