ESAB Heliarc 250 Instruction Manual page 8

SECTION 2
Fig. 2.2 - Input Terminal Board
It is of the utmost importance that the chassis be
connected to an approved electrical ground to pre-
vent accidental shocking. Take care not to connect
the ground wire to any of the primary leads.
4. Recheck all connections to make sure they are
tight, well insulated, and that the proper connection
has been made.
C. EXTERNAL PRIMARY/SECONDARY CONNEC-
TIONS
Verify that all electrical connections comply with
local electrical codes and especially with require-
ments established in booklet ADI-5054 "High Fre-
quency Stabilized Arc Welding Equipment", which is
packed with this power source.
Refer to Interconnection Diagram, Figure 2-1, for typical
primary input, secondary output, process gas and water,
and torch connections that are required for this unit's
welding application.
Before making any connections to the power source's
output receptacles, make sure that all primary input
power to the machine is deenergized (off) at the
customer's disconnect switch.
8
Customer's
Input Cable
Connection
* DOUBLE LINKS PROVIDED
2-3
The proper operation of the welding machine depends to
a great extent on the use of output cables that are
insulated copper, adequately sized, in good condition,
and properly connected to the machine using UL listed
pressure wire connectors. It is recommended that the
output cables be kept as short as possible (this is
particularly important for tig applications using
ACHF), and be of adequate current carrying capacity.
The resistance of the output cables and connections
causes a voltage drop which is added to the voltage of the
arc. Excessive cable resistance may result in overload-
ing as well as reducing the maximum current output of
which the power source is capable. The welding output
terminals are located on the front panel. The following
table will prove useful for selecting the recommended
output cable size.
Welding Total Length (Feet) of Cable in Weld Circuit*
Current
50 100
200 2 2
250 1 1
* Total cable length includes work and electrode cables. Cable size
is based on direct current, insulated copper conductors, 40% duty
cycle, and a voltage drop of 4 or less volts. The welding cable
insulation must have a voltage rating that is high enough to
withstand the open circuit voltage of the machine.
D. ACCESSORIES
1. FC-4 Foot Current and Contactor Control, P/N
679662. This device provides the operator with
remote control of current and contactor operation
at the welding station. Interconnection of these
functions to the main unit is provided by a mating
25-foot cable/plug assembly. By depressing the
foot pedal, the weld-start sequence circuit will en-
ergize, and the welding current will increase or
decrease within the range preset on the power
source Current Control potentiometer.
2. TC-1A Torch Current and Contactor Control, P/
N 34718 (25-ft lg). This remote fingertip control is
designed to be taped to any Tig torch handle and to
provide the operator with complete contactor con-
trol and variable control of the welding current. By
simply rotating the knob clockwise (off of zero), the
integral switch will energize the contactor. Further
rotation (clockwise) will increase the output current
up to the limit preset on the power source main
control.
3. Torch Switch Assembly, P/N 674038. This de-
vice is designed to be attached to any tig welding
torch, and provides the operator with remote
INSTALLATION
150 200 250
1 1 1/0
1/0 1/0 1/0