790 APPENDIX III 



the penstock intake is not taking place, as indicated by excessive amounts 

 of air in the discharge, or presence of vortices in the intake. Precautions 

 against leakage of water from penstock or turbine casing should be taken, 

 particularly through drain valves, relief valves or other connections. The 

 rate of fall of the standing water surface in the turbine casing below the 

 point of intake through the turbine gates should be observed during shut- 

 down as an indication of possible leakage. 



(6) Unsteady Conditions. Tests should not be made under conditions 

 of changing head, load or speed. Variations of load during an individual 

 run shall not exceed 3 per cent above or 3 per cent below the average load, 

 and variations of head shall not exceed 2 per cent above or 2 per cent below 

 the average head, and variations of speed shall not exceed 1 per cent above 

 or 1 per cent below the average speed. Instrument calibrations and cor- 

 rection curves should be prepared in advance of the test, and measures 

 taken to enable results to be computed as quickly as possible during the 

 course of the test or before the work of testing shall be considered to have 

 been completed. 



6. Calibration of Instruments. Important instruments shall be installed 

 in duplicate and all instruments shall be calibrated both before and after 

 the test. Only the readings of those instruments in which the two cali- 

 brations agree shall be used in computing the results. Where results are 

 appreciably altered by reason of instrument calibrations made after the 

 test disagreeing with those made before, the test shall be repeated. 



6. Conduct of Test. Both parties to the contract shall be represented and 

 shall have equal rights in determining the methods and conduct of the test. 



All points of disagreement shall be settled to the satisfaction of both 

 parties, and the results of the test be agreed on as acceptable, before the 

 test shall be considered terminated or the test equipment removed. 



The measurement of the various quantities entering into the computa- 

 tion of turbine power and efficiency shall be in accordance with the follow- 

 ing regulations: 



MEASUREMENT OF POWER OUTPUT 



7. (a) By Electrical Measurement of Generator Output and Generator 

 Losses. In turbines direct-connected to electrical generators the power 

 output of the turbine may be measured as provided below. 



The intent of the provisions contained herein is that the power output 

 of the turbine shall be taken as the power output of the generator plus all 

 losses supplied by the turbine up to the point of measurement. 



The generator may be tested for efficiency either in the shops of the builder 

 or after installation, the losses being determined either by direct measurement 

 of input and output or by the separate-loss method; the electrical measure- 

 ments being carried out in accordance with the Standardization Rules of 

 the American Institute of Electrical Engineers of Septermber, 1916, but 

 subject to the provisions contained herein. 



The generator losses and efficiency as herein defined are for the generator 

 considered as a dynamometer, and are independent of the performance 

 guarantees of the generator which are not within the scope of this code. 



