General Description; Recommended Processes; Design Features And Advantages; Welding Capability - Lincoln Electric IDEALARC R3R-300 Service Manual

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GENERAL DESCRIPTION

The Idealarc R3R is an SCR controlled constant cur-
rent DC output power source for welding and cutting.
The R3R-300 uses a single range potentiometer con-
trol. The R3R-400 and R3R-500 have separate low
and high range controls. The welder's unique combi-
nation of 3 phase transformer, SCR/Diode bridge rec-
tifier, arc control choke, and solid state control system
deliver outstanding arc characteristics. For stick weld-
ing, an Arc Force Control enables the Idealarc-R3R to
create a soft welding arc for critical applications or a
forceful driving arc for heavy duty applications.

RECOMMENDED PROCESSES

The Idealarc R3R is recomended for stick and DC TIG
welding and air/carbon arc gouging.
OPERATION

DESIGN FEATURES AND ADVANTAGES

• Input line voltage compensation keeps output con-
stant for fluctuations of ± 10%.
• 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 reduces chance of acci-
dental 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 R3R has the following duty cycle ratings.
If the duty cycle is exceeded, a thermal protector will
shut off the machine output until it cools to normal
operating temperature. The amber thermal protection
indicator light will turn on until the machine cools.
60% Duty Cycle*
R3R-300
R3R-400
R3R-500
*Based on a 10 minute time period. For example, a 60% duty cycle
means 6 minutes on and 4 minutes off.
IDEALARC R3R
Amps Volts
300 32
400 36
500 40
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