Linkoln Electric Square Wave TIG 200 Manuel De L'opérateur page 14

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SQUARE WAVE TIG 200
MACHINE GROUNDING AND HIGH FREQUENCY
INTERFERENCE PROTECTION
The welder must be grounded. See your local and national electrical
codes for proper grounding methods.
The high frequency generator, being similar to a radio transmitter,
can be blamed for radio, TV and electronic equipment interference
problems. These problems may be the result of radiated interference.
Proper grounding methods can reduce or eliminate radiated inter-
ference.
Radiated interference can develop in the following four ways:
1. Direct interference radiated from the welder.
2. Direct interference radiated from the welding leads.
3. Direct interference radiated from feedback into the power lines.
4. Interference from re-radiation of "pickup" by ungrounded
metallic objects.
Keeping these contributing factors in mind, installing equipment per
the following instructions should minimize problems.
1. Keep the welder power supply lines as short as possible and
enclose as much of them as possible in rigid metallic conduit or
equivalent shielding for a distance of 50 feet (15.2m). There
should be good electrical contact between this conduit and the
welder case ground. Both ends of the conduit should be
connected to a driven ground and the entire length should be
continuous.
2. Keep the work and electrode leads as short as possible and as
close together as possible. Lengths should not exceed 25 ft
(7.6m). Tape the leads together when practical.
3. Be sure the torch and work cable coverings are free of cuts and
cracks that allow high frequency leakage.
4. Keep the torch in good repair and all connections tight to reduce
high frequency leakage.
5. It is recommended that the work piece should be connected to an
earth ground close to the work clamp, using one of the following
methods:
a) A metal underground water pipe in direct contact with the
earth for ten feet or more.
b) A 3/4" (19mm) galvanized pipe or a 5/8" (16mm) solid
galvanized iron, steel or copper rod driven at least eight
feet into the ground.
The ground should be securely made and the grounding cable should
be as short as possible using cable of the same size as the work
cable, or larger. Grounding to the building frame electrical conduit or
a long pipe system can result in re-radiation, effectively making these
members radiating antennas.
6. Keep cover and all screws securely in place.
7. Electrical conductors within 50 ft (15.2m) of the welder should be
enclosed in grounded rigid metallic conduit or equivalent
shielding, wherever possible. Flexible metallic conduit is
generally not suitable.
8. When the welder is enclosed in a metal building, the metal
building should be connected to several good earth driven
electrical grounds (as in 5 (b) above) around the periphery of the
building.
Failure to observe these recommended installation procedures can
cause radio or TV and electronic equipment interference problems
and result in unsatisfactory welding performance resulting from lost
high frequency power.
A-7
INSTALLATION