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What are the advantages and disadvantages of utilising prods for magnetic particle inspections?


Prods induce a circular magnetic field by sending a high amperage (1000A typically) current through the testpiece. The high amperage can cause arcing between the electrodes and test surface. Contact points must be carefully cleaned, and electrode materials chosen to prevent contamination of the testpiece.

  • Variable field strength
  • Danger of arcing
  • AC or DC fields
  • Danger of overheating
  • Useful in confined spaces
  • Heavy transformer required
  • Low voltages
  • Possible to switch on without creating field
  • No poles to attract particles
  • Possible contamination of the testpiece by the electrode
  • Control of amperage
  • Must have good electrical contact
  • Usually two-man operation

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