Input Connections - Lincoln Electric PRECISION TIG 185 SVM169-A Service Manual

A-5
The high frequency generator, being similar to a radio
transmitter, may cause radio, TV and electronic equip-
ment 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 mini-
mize problems.
1. Keep the welder power supply lines as short as pos-
sible 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 pos-
sible 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 frequen-
cy 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 fol-
lowing 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 dri-
ven at least eight feet into the ground.
The ground should be securely made and the ground-
ing 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 re-radiation, effectively making
these members radiating antennas.
INSTALLATION
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 metal-
lic conduit or equivalent shielding, wherever possi-
ble. Flexible metallic conduit is generally not suit-
able.
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 unsatis-
factory 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.
208/230 volt models have a NEMA 6-50P plug
attached to the #8-3 input power cord and a NEMA 6 -
50R receptacle is included with the Ready-Pak mod-
els. Other voltage models have an input power cord
but no plug or receptacle.
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 1 circuit breakers. Using fuses or circuit breakers
smaller than recommended may result
in "nuisance" shut-offs from welder inrush currents
even if not welding at high currents.
1 Also called "inverse time" or "thermal/magnetic" circuit breakers;
circuit breakers which have a delay in tripping action that decreases
as the magnitude of the current increases.
PRECISION TIG 185
A-5