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PC 70i, 100i Operating Manual
Input Power
Each unit incorporates an INRUSH circuit and input voltage sensing circuit. When the MAIN CIRCUIT
SWITCH is turned on, the inrush circuit provides a pre-charging of the input capacitors. The cutting machine
will turn on after the input capacitors have charged to full operating voltage (after approximately 3 seconds).
Introduction
The importance of correct installation of high frequency cutting equipment cannot be overemphasized.
Interference due to high frequency initiated or stabilized arc is almost invariably traced to improper installation.
The following information is intended as a guide for personnel installing high frequency cutting machine.
Warning
Explosives
The high frequency section of this machine has an output similar to a radio transmitter. The machine
should NOT be used in the vicinity of blasting operations due to the danger of premature firing.
Computers
It is also possible that operation close to computer installations may cause computer malfunction.
High Frequency Interference
Interference may be transmitted by a high frequency initiated or stabilized arc cutting 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 Cutting Leads
Radiated interference from cutting 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
cutting leads .Effective grounding of such objects will prevent re-radiation in most cases.