CARBONE DIGI-CUT70, Operator'S Manual, Page: 12 / 33

A-4 INSTALLATION A-4
MACHINE GROUNDING AND HIGH
FREQUENCY INTERFERENCE
PROTECTION
This 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, may cause radio, TV and
electronic equipment interference problems. These
problems may be the result of radiated interference.
Proper grounding methods can reduce or eliminate
radiated interference.
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 rubber
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 The work piece must 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 along pipe system can result in
reradiation, 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.
INPUT CONNECTIONS
Be sure the voltage, phase, and frequency of the
input power is as specified on the rating plate,
located on the rear of the machine.
Have a qualified electrician provide input power
supply to the receptacle or cord in accordance with
all local and national electrical codes. Use a single
phase line or one phase of a two or three phase
line.
Choose an input and grounding wire size according
to local or national codes. Refer to
the Technical
Specifications page at the beginning of this section.
Fuse the input circuit with the recommended super
lag fuses or delay type circuit breakers.