Tweco 300 ACDC Arcmaster - Manual (Page 23)

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3.07 High Frequency Interference
Interference may be transmitted by a high frequency initiated or stabilized arc welding machine in the
following ways:
Direct Radiation
Radiation from the machine can occur if the case is metal and is not properly grounded. It can occur
through apertures such as open access panels. The shielding of the high frequency unit in the
Power Source will prevent direct radiation if the equipment is properly grounded.
Transmission via the Supply Lead
Without adequate shielding and filtering, high frequency energy may be fed to the wiring within the
installation (mains) by direct coupling. The energy is then transmitted by both radiation and
conduction. Adequate shielding and filtering is provided in the Power Source.
Radiation from Welding Leads
Radiated interference from welding leads, although pronounced in the vicinity of the leads,
diminishes rapidly with distance. Keeping leads as short as possible will minimize this type of
interference. Looping and suspending of leads should be avoided where possible.
Re-radiation from Unearthed Metallic Objects
A major factor contributing to interference is re-radiation from unearthed metallic objects close to the
welding leads. Effective grounding of such objects will prevent re-radiation in most cases.