CONTENTS xiii 



CHAPTER XIII 



I'A.iK 



THE CALIBKATHKN OF IN>THUMENTS 593 



Accuracy and Precision Calibration Before and After Tests 

 Choice of Instruments Errors of Reading MECHANICAL ERRORS 

 Friction Springs Balancing Scale Errors Corrosion ELEC- 

 TRICAL AND MAGNETIC ERRORS Shunts Millivoltmeter Leads 

 Thcrmo-electromotive Forces Effect of External Tempera- 

 tures -Internal Heating Errors Stray Fields Electrostatic At- 

 traction Kddy Currents Current Distribution Frequency and 

 Wave Form Use of Transformers Direct-current Instruments 

 Voltmeter Calibration by Standard Cell Ammeter Calibration 

 Calibration by Means of Potentiometer Alternating-current Am- 

 meters and Voltmeters The Xorthrup Alternating- and Direct- 

 current Comparator Wattmeters. 



CHAPTFK XIV 



DKTI.KMI FORM '!- 



Contact Method for Determining Wave Forms Use of Potenti- 

 ometer Principle Integrating Methods for Determining ^ 

 Form F.m.f. Waves Flux \Va\ < >ndenser and Syn- 



chronous Commutator Determination of the Average Values of 

 B and Current Waves Determination of Form 



r The Oscillograph Theory of t he Oscillograph The Flec- 

 trostatic Oscillograph Adjust rm-nt > * >scillograph 

 The Braun Tube Perman. - || by Braiin Tubes BfeotlO- 



'ic Tubes ft ,n>idcrations WAVK ANALYSIS Kunge 



Metho<l of (Iroupi.v. rms Cosine Terms ILLUS- 



TRATION OP THE USE OP A TWELVE-POINT SCHEDULE FOR THE 

 IMS OF WAVES COM \IMN<- <>\\.\ ODD HARMONICS Fischer- 

 Ifinnen Method of Harmonic Analy/.ers Fxperimrntal 



Analysis: I.aus Method. 



CHAPTKP, XV 



CABI \a o7'J 



FAULT LOCATION Location of Grounds and Crosses Blavier 



Test The Farth Overlap Test The Volt-ammeter Test Loop 



Testa Two-ammeter Loop Test Murray Loop Test Varley 



Loop Test Determination of the Total Resistance of the Defe, t- 



< 'ondu< tor Fisher Loop Test Corrections for Conductors 



Locating Faults in I'nderground High- 



ri Cables Location of Total Disconnection Breakdown 



High-volt age Cables Measurement of Peak Voltage. 



i. DLFIMIK.N- .i TIM i \i. !'MT- INTHK TMII 7<)"> 



. 707 



