Lincoln Electric SA-250 Welder Operation, Duty Cycle, Control of Welding Current, Idler Operation

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.

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.

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 eliminates the possibility of setting this switch between the designated points.

ARC RAYS can burn.

• Wear eye, ear, and body protection.

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

CAUTION

DO NOT TURN THE “CURRENT RANGE SELEC- TOR” WHILE WELDING because the current may arc between the contacts and damage the switch.

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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.

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:

ORDERING	ENGINE	FULL	HIGH	LOW
INFO.		LOAD	IDLE	IDLE
K1283-	Perkins	1725	1800	1350
ALL	Diesel

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.

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