REGULATORS 205 



sketch showing the numbers that have been given to 

 the various circuits. Record the temperature of each 

 coil, or of the oil. 



Boost and Lower 



The boost and lower test is made at normal voltage and 

 frequency. On three-phase regulators, apply a balanced 

 three-phase voltage to the primary using a three-pole 

 double-throw switch to transfer the voltmeter from the 

 primary to the secondary. (Primary and secondary here 

 refer to the voltage to be controlled and the controlled 

 voltage respectively.) The regulator must be connected 

 as in service, the primaries being in shunt and the 

 secondaries in series with the circuit to be controlled. 

 A voltmeter should be placed across one phase for 

 a check. Fig. 69 shows the proper connections for 

 a three-phase boost and lower test. Adjust the voltage 

 by the voltmeter that is used on both primary and 

 secondary, and note the readings on the check volt- 

 meter. Throw the three-pole switch to the secondary 

 and read the voltage on the corresponding phase of the 

 secondary. Do this for all three phases at maximum 

 boost, neutral and maximum lower. A curve of about 

 twenty points should be taken on one phase. 



The voltage balance should be taken at maximum 

 boost, neutral, and maximum lower. Count the turns 

 of the handwheel from maximum boost to neutral 

 and from neutral to maximum lower and record the 

 number to afford a check on the mechanical construc- 

 tion. Maximum boost and lower do not always come 

 at extreme ends of segment. The voltage readings 

 should be taken at every turn of the handwheel 

 for a few turns from each end, to locate the maximum 

 positions. Check the index on the handwheel to see that 

 it indicates the proper direction for boost and lower. 

 The induced voltage in the secondary coil should be 

 measured and recorded, as well as the boost and 

 lower. 



In some types of IRH regulators, the terminals of 

 the secondary coils are crossed instead of being directly 



