REGULATORS 203 



Cold Resistance 



Before starting the tests, carefully check all circuits. 

 If the secondary coils have two studs on each end per 

 phase, test to see if the studs are connected in multiple 

 or if each secondary consists of two separate coils which 

 are connected in multiple by the cable lugs. If the regu- 

 lator is six-phase IRH, test to see if there are two primary 

 circuits. On diametrically-connected IRH's (Fig. 68), 

 primaries 1-3-5 should be one set, and 2-4-6 the other. 



To Rotary 

 i ^ 3 4. 5 e 



Secondones 

 l ^ 3 4 56 



To Transformer 



Fig. 68 

 Six-Phase Regulator 



On a delta-connected IRH regulator, 1-4, 2-5 and 3-6 

 should give proper circuits. If each secondary circuit 

 has two coils that are connected in multiple by the cable 

 lugs, the top stud on one side is generally connected to 

 the bottom stud on the opposite side, and vice versa. 

 Measure the resistance as on a transformer. In 

 recording the secondary resistances, a note should be 

 made of the place on which the drop lines were placed. 

 Take the resistance of each secondary coil and make a 



