Lincoln Electric PERKINS SA-250 - Manual (Page 15)

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.
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 Control” switch in
“High Idle” position. Allow it to run at high idle speed
for several minutes to warm the engine. The operat-
ing speeds are as follows:
The idler is controlled by an “Idler Control” toggle
switch on the welder control panel. The switch has
two positions as follows:
1. In the “High” position, the idler is off, and the
engine runs at the high speed controlled by the
governor.
2. In the “Automatic” / position, the
idler operates as follows:
a. When welding or drawing power for lights or
tools (approximately 100-150 watts minimum)
from the receptacles, the engine operates at full
speed.
b. When welding ceases or the power load is
turned off, a preset time delay of about 15 sec-
onds starts. This time delay cannot be adjust-
ed.
c. If the welding or power load is not re-started
before the end of the time delay, the idler
reduces the engine to low idle speed.
ORDERING
INFO.
ENGINE FULL
LOAD
HIGH
IDLE
LOW
IDLE
K1283-
ALL
Perkins
Diesel
1725 1800 1350
WELDER OPERATION
Duty Cycle
The NEMA output rating of the SA-250 is 250
amperes at 30
(1) arc volts on a 60% duty cycle. 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.
(1) The Lincoln “plus output” rating at 60% duty cycle
is 250 amperes at 40 volts.
Control of Welding Current
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 Range
Selector” to the 190-120 position and then adjust the
“Fine Current Adjustment” for 175 amps.
– 14 –
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.
WARNING
CAUTION
CAUTION