206 



COMMERCIAL ELECTRICAL TESTING 



opposite each other. (See Fig. 70.) In such cases take 

 care to properly record the boost and lower and make a 

 clear sketch showing the arrangement of the secondary 

 terminals. Boost and lower may be taken on six-phase 

 IRH regulators as though they consisted of two separate 

 regulators; that is, the test may be made on 1-3-5 and 

 then on 2-4-6. Six-phase voltage must, however, be 

 applied and a set of six-phase boost or lower readings 

 taken to determine if the regulator is satisfactory. 



Fig. 70 

 Regulator Six-Phase 



Fig. 71 gives the method of obtaining six-phase voltage 

 which should be tested before proceeding. With the 

 connections shown, the voltages corresponding to the 

 six sides of a hexagon can be obtained by reading 1-2, 

 2-3, 3-4, 4-5, 5-6 and 6-1. Unless six-phase voltage 

 is used, don't try to make a boost or lower test. The 

 induced secondary voltage of each secondary coil should 

 be recorded. 



The boost and lower test on IRH, or diametrically 

 connected regulators, must be made by applying a six- 

 phase diametrically connected voltage, tested as pre- 

 viously described. The transformer connections are 

 shown in Fig. 72, a neutral point being made so that 

 six-phase voltage may be read. In taking boost and 

 lower, read the diametrical voltage, carefully checking the 

 six-phase boost or lower and recording it as the diamet- 

 rical boost or lower. Measure and record the induced 

 voltage across each seccndary coil. 



