CHAPTER VII 



REGULATION TESTS FOR SPEED AND 

 VOLTAGE. INPUT-OUTPUT TESTS 



Regulation Test Speed Voltage 



Shunt regulation should be taken on shunt generators. 

 A reading should first be taken at no-load normal 

 voltage; then, without changing the rheostat, } full 

 load should be thrown on and a reading taken of amperes 

 armature, volts armature, amperes field and volts field. 

 Holding J full load, the voltage should be brought up 

 to normal and the same readings taken. The load 

 should then be increased to J full load, the rheostat 

 remaining in the same position as before, and similar 

 readings taken. This test is repeated for f and full 

 load. With full load on the machine the voltage should 

 be brought up to normal. Without altering the position 

 of the field rheostat, the load is then taken off the 

 machine and the rise in voltage observed. A curve 

 should be plotted with amperes armature as abscissae 

 and volts as ordinates. 



If the voltage should drop to zero when \ load is 

 put on the machine, the load should be applied in smaller 

 increments. Speed should be kept constant throughout 

 the test. 



Speed regulation is important in the operation of 

 motors, particularly in the case of direct current 

 machines. The speed on all motors should be adjusted 

 while the machine is hot, by shifting the brushes, but 

 should never be corrected at the sacrifice of commu- 

 tation. It should always be adjusted for full load 

 unless instructions specifically state otherwise. 



If special tests are required for a motor, a hot speed 

 curve should be included. Starting with no load and 

 increasing to full load, the speed should be carefully 



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