Welder Operation; Duty Cycle; Control Of Welding Current - Lincoln Electric CLASSIC 300D KUBOTA IM843-C Operator's Manual

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Larger machines with a capacity of 350 amperes and
higher, which are operated at low or no-load condi-
tions for extended periods of time are especially sus-
ceptible to the conditions described above. To
accomplish successful engine break-in, most diesel-
powered equipment needs only to be run at a reason-
ably heavy load within the rating of the welder for
some period of time during the engineʼs early life.
However, if the welder is subjected to extensive light
loading, occasional moderate to heavy loading of the
engine may sometimes be necessary. Caution must
be observed in correctly loading a diesel/generator
unit.
1. Connect the welder output studs to a suitable
resistive load bank. Note that any attempt to
short the output studs by connecting the welding
leads together, direct shorting of the output studs,
or connecting the output leads to a length of steel
will result in catastrophic damage to the generator
and voids the warranty.
2. Set the welder controls for an output current and
voltage within the welder rating and duty cycle.
Note that any attempt to exceed the welder rating
or duty cycle for any period of time will result in
catastrophic damage to the generator and voids
the warranty.
3. Periodically shut off the engine and check the
crankcase oil level.

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.
------------------------------------------------------------------------
OPERATION

DUTY CYCLE

The NEMA output rating of the CLASSIC 300D KUB-
OTA is 300 amperes at 32 arc volts on a 60% duty
cycle (consult Specifications in this manual for alter-
nate 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

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.
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.
CLASSIC 300D KUBOTA
CAUTION
CAUTION
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