Electricity: measuring and testing – Magnetic – With means to create magnetic field to test material
Patent
1984-12-13
1987-09-08
Eisenzopf, Reinhard J.
Electricity: measuring and testing
Magnetic
With means to create magnetic field to test material
324209, 73DIG2, 73801, G01N 2782, G01B 724
Patent
active
046927018
ABSTRACT:
In a method for testing steam turbine rotors for embrittlement to determine which rotors to retire and which rotors to continue in operation, a varying magnetic field is applied to the rotor in a waveform to produce a detectable Barkhausen effect in the flux density developed in the rotor. The resulting Barkhausen burst of pulses is detected and is displayed on an oscilloscope. In addition, the pulse amplitude distribution of the pulses in the burst is plotted. The oscilloscope display and the pulse height distribution curve are compared with corresponding representations of the Barkhausen effect produced from a test sample known not to be embrittled, or from the rotor itself at a previous time, to make a determination of whether the rotor has become embrittled and whether to continue operation of the rotor.
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Dundas Robert E.
Tatar Fred W.
Edmonds Warren S.
Eisenzopf Reinhard J.
Factory Mutual research
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