Table Of Contents - Raytech mini-ATOS Instruction Manual

Contents
1 Safety Precautions .............................................................................................................. 6
1.1 Operators Qualifications .............................................................................................. 6
1.2 High Voltage Apparatus Accessibility During the Tests ................................................ 6
1.3 Ground the Instrument ................................................................................................. 6
1.4 Before Applying Power ................................................................................................ 7
1.5 Keep Away from Live Circuits ...................................................................................... 7
1.6 Do Not Operate in An Explosive Atmosphere .............................................................. 7
1.7 Do Not Substitute Parts or Modify Instrument .............................................................. 7
1.8 Do Not Operate in A Condensing Humidity or Under Rain ........................................... 7
1.9 Always Keep Distance from the Test Object During the Tests ..................................... 7
2 Unpacking ........................................................................................................................... 9
3 Introduction ........................................................................................................................10
4 Calculation and Measurement Methods .............................................................................11
4.1 Turns Ratio Measurement...........................................................................................11
4.1.1 Principle ...............................................................................................................11
4.1.2 Voltage Ratio and Turns Ratio .............................................................................11
4.1.3 Relative Error .......................................................................................................13
4.2 DC Resistance Test ....................................................................................................14
4.2.1 Principle ...............................................................................................................14
4.2.2 Temperature Correction .......................................................................................15
4.2.3 Resistance Deviation ...........................................................................................16
4.3 Demagnetization .........................................................................................................17
4.3.1
Raytech SPP Demagnetization Method ...............................................................18
4.3.2 Three-Phase Transformer Demagnetization ........................................................18
4.4 Magnetic Balance .......................................................................................................19
4.5 Short Circuit Impedance .............................................................................................20
4.5.1 Principle ...............................................................................................................20
4.5.2 Short Circuit Jumpers ..........................................................................................21
4.5.3 Temperature Correction .......................................................................................21
4.5.4 Short circuit impedance deviation ........................................................................21
4.6 Dynamic Resistance Measurement (DRM) .................................................................22
4.7 OLTC Motor Drive Current ..........................................................................................24
5 Measurement Setup ...........................................................................................................25
5.1 Connecting Test Cables to Transformer Terminals .....................................................25
90297-0.24 Instruction Manual mini-ATOS
Preliminary
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