Welder Operation; Duty Cycle; Control Of Welding Current; Idler Operation - Lincoln Electric SA-250 Operator's Manual

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WELDER OPERATION

WARNING
ELECTRIC SHOCK can kill.
• Do not touch electrically live parts or
electrode with skin or wet clothing.
• Insulate yourself from work and ground.
FUMES & GASES can be dangerous.
• Keep your head out of the fumes.
• Use ventilation or exhaust to remove
fumes from breathing zone.
WELDING SPARKS can cause fire or
explosion.
• Keep flammable material away.
ARC RAYS can burn.
• Wear eye, ear, and body protection.

DUTY CYCLE

The NEMA output rating of the SA-250 is 300
amperes at 32 arc volts on a 60% duty cycle (consult
Specifications in this manual for alternate ratings).
Duty cycle is based on a ten minute period; thus, the
welder can be loaded at rated output for six minutes
out of every ten minute period.

CONTROL OF WELDING CURRENT

CAUTION
DO NOT TURN THE "CURRENT RANGE SELEC-
TOR" WHILE WELDING because the current may
arc between the contacts and damage the switch.
------------------------------------------------------------------------
The "Current Range Selector" provides five overlap-
ping current ranges. The "Fine Current Adjustment"
adjusts the current from minimum to maximum within
each range. Open circuit voltage is also controlled by
the "Fine Current Adjustment" permitting control of the
arc characteristics.
A high open circuit voltage setting provides the soft
"buttering" arc with best resistance to pop-outs pre-
ferred for most welding. To get this characteristic, set
the "Current Range Selector" to the lowest setting that
still provides the current you need and set the "Fine
Current Adjustment" near maximum. For example: to
obtain 175 amps and a soft arc, set the "Current
OPERATION
Range Selector" to the 190-120 position and then
adjust the "Fine Current Adjustment" for 175 amps.
When a forceful "digging" arc is required, usually for
vertical and overhead welding, use a higher "Current
Range Selector" setting and lower open circuit volt-
age. For example: to obtain 175 amps and a forceful
arc, set the "Current Range Selector" to the 240-160
position and the "Fine Current Adjustment" setting to
get 175 amps.
Some arc instability may be experienced with EXX10
electrodes when trying to operate with long arc tech-
niques at settings at the lower end of the open circuit
voltage range.
DO NOT attempt to set the "Current Range Selector"
between the five points designated on the nameplate.
------------------------------------------------------------------------
These switches have a spring loaded cam which
almost eliminates the possibility of setting this switch
between the designated points.

IDLER OPERATION

Start the engine with the "Idler" switch in the "High"
position. Allow it to run at high idle speed for several
minutes to warm the engine. See Specifications for
operating speeds.
The idler is controlled by the "Idler" toggle switch on
the welder control panel. The switch has two posi-
tions as follows:
1. In the "High"
vates, and the engine goes to high idle speed. The
speed is controlled by the governor.
2. In the "Auto"
ates as follows:
• When welding or drawing power for lights or tools
(approximately 100-150 watts minimum) from the
receptacles, the idler solenoid activates and the
engine operates at high idle speed.
• When welding ceases or the power load is turned off,
a preset time delay of about 15 seconds starts. This
time delay cannot be adjusted.
• If the welding or power load is not re-started before
the end of the time delay, the idler solenoid deacti-
vates and reduces the engine to low idle speed.
SA-250
CAUTION
position, the idler solenoid acti-
/ position, the idler oper-
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