Lincoln Electric SVM194-A service manual B2.3, Contacts and damage the switch

DUTY CYCLE 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.

Lincoln Electric selects high quality, heavy-duty industrial engines for the portable welding machines we offer. While it is normal to see a small amount of crankcase oil consumption during initial operation, excessive oil use, wet stacking (oil or tar like substance at the exhaust port), or excessive smoke is not normal.

Larger machines with a capacity of 350 amperes and higher, which are operated at low or no-load conditions for extended periods of time are especially susceptible to the conditions described above. To accomplish successful engine break-in, most diesel-powered equipment needs only to be run at a reasonably 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 resis- tive load bank. Note that any attempt to short the output studs by connecting the welding leads togeth- er, direct shorting of the output studs, or connecting the output leads to a length of steel will result in cat- astrophic damage to the generator and voids the warranty.

2. Set the welder controls for an output current and volt- age 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 dam- age to the generator and voids the warranty.

3. Periodically shut off the engine and check the crankcase oil level.

WELDER OPERATION

B2.3

ENGINE BREAK-IN

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OPERATION	B2.3
The NEMA output rating of the Classic® 300D Perkins 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 SELECTOR”
WHILE WELDING because the current may arc between
the contacts and damage the switch.
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The “Current Range Selector” provides five overlapping cur-
rent ranges. The “Fine Current Adjustment” adjusts the cur-
rent from minimum to maximum within each range. Open cir-
cuit voltage is also controlled by the “Fine Current
Adjustment” permitting control of the arc characteristics.

A high open circuit voltage setting provides the soft “butter- ing” arc with best resistance to pop-outs preferred 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 maxi- mum.

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 voltage.

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 elec- trodes when trying to operate with long arc techniques at set- tings at the lower end of the open circuit voltage range.

CAUTION

DO NOT attempt to set the “Current Range Selector” between the five points designated on the nameplate.

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These switches have a spring loaded cam which almost elim- inates the possibility of setting this switch between the des- ignated points.

CLASSIC® 300D & 300G