General Description - Lincoln Electric IDEALARC SVM 122-A Service Manual

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GENERAL DESCRIPTION

The Idealarc DC-400 is an SCR controlled three-phase
input, DC output power source for welding and cut-
ting. It uses a single range potentiometer control. The
welder's unique combination of transformer, three-
phase semiconverter rectifier, capacitor bank, arc con-
trol choke, and solid state control system deliver out-
standing arc characteristics in the constant voltage
mode. For stick welding, an Arc Force Control enables
the Idealarc-400 to perform much like the R3R-500.
RECOMMENDED PROCESSES
The Idealarc DC-400 is recomended for all open arc
processes including Innershield
gas procedures within its capacity of 60 to 500 amps.
It also can perform stick and TIG welding and air/car-
bon arc gouging up to 5/16" (8 mm) diameter. A mode
switch on the front control panel selects CV (FCAW,
GMAW), CV Submerged Arc, or CC (stick/TIG).
The Idealarc DC-400 can be connected to wire feed-
ing equipment, including:
• Automatic wire feeders NA-3, NA-5, and NA-5R.
(Requires the DC-400 Diode Kit option to use the
cold start and cold electrode sensing features of
these feeders.)
• Semi-automatic wire feeders LN-7, LN-7 GMA, LN-
8, LN-9, LN-9 GMA, LN23P, LN-25, LN-742.
• Tractors LT-56, LT-7.
OPERATIONAL FEATURES AND
CONTROLS
The following operational controls are standard on the
Idealarc DC-400:
• Power Source Pilot Light
• ON/OFF Power Toggle Switch
• Output Control Potentiometer
• Output Control Switch (with Local or Remote posi-
tions)
• Output Terminals On or Remote Switch
• Arc Force Selector (for CC stick or TIG processes
only)
• Auxiliary Power Connections for Wire Feeder and
Other Equipment (115V and 42V)
• Mode Switch
• Arc Control
• Thermal Protection Indicator Light
OPERATION
® and all solid wire and
IDEALARC DC-400
LINCOLN
ELECTRIC
• DC Ammeter
• DC Voltmeter
• Voltmeter "+" Electrode or "-" Electrode Switch
DESIGN FEATURES AND ADVANTAGES
• Input line voltage compensation keeps output con-
stant for fluctuations of ± 10%.
• SCR control extends life of mechanical contactors.
• Hinged front control panel provides easy access to
printed circuit boards and other control circuitry.
• Fully enclosed fan motor with permanently lubri-
cated, sealed ball bearings needs no maintenance.
• Fully recessed control panel protects controls and
minimizes accidental contact.
• Recessed output terminals and hinged terminal
cover reduce chance of accidental contact.
• Low profile case permits installation under a work-
bench.
• Removable rear access panel provides easy access
to input contactor and input lead connections.
• Removable case sides provide easy access for ser-
vice or inspection, even when machines are stacked.
• Dripproof enclosure design permits outdoor operation.
• Double-dipped transformer, SCR bridge, and choke
resist corrosion.
WELDING CAPABILITY
The Idealarc DC-400 has the following duty cycle
ratings. If the duty cycle is exceeded, a thermal pro-
tector will shut off the machine output until it cools to
normal operating temperature.
protection indicator light will turn on until the machine
cools.
Duty Cycle* Amps
100% 400
60% 450
50% 500
*Based on a 10 minute time period. For example, a 60% duty cycle
means 6 minutes on and 4 minutes off.
LIMITATIONS
The Idealarc DC-400 has no provisions for paralleling.
®
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The amber thermal
Volts
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38
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