Lincoln Electric SVM114-C service manual Optional Circuits, Contactor, GAS Solenoid, Later Models

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E-4	THEORY OF OPERATION	E-4
	FIGURE E.4 – OPTIONAL CIRCUITS.

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ELECTRODE INPUT CABLE

TO WORK

SENSING LEAD

			OPTIONAL
			CONTACTOR
			CONDUCTOR	GUN CABLE
			BLOCK
COLD			M		GUN
		OPTIONAL	O	HALL	TRIGGER
INCH			T		CONNECTOR
SWITCH		CONTACTOR	O	EFFECT
		BOARD	R	MODULE
P
O S
L W			ARMATURE VOLTAGE
A I	VOLT
R T
I C	METER	CONTROL	RPM FEEDBACK
T H
Y		BOARD
WIRE FEED			RANGE
			SWITCH
MODE SWITCH
			WIRE SPEED
			CONTROL
		SOLENOID	GAS
		PC BOARD	SOLENOID
		EARLY MODELS ONLY - LATER MODELS HAVE CIRCUITRY
			INCLUDED ON CONTROL BOARD

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OPTIONAL CIRCUITS

CONTACTOR

The contactor, contactor PC board, and cold inch switch are commonly incorporated in the LN-25™. This feature enables the user to have an electrically “COLD” gun even though the power sources output terminals are electrically “HOT”. Upon receiving a command from the control board, the contactor PC board sends a current signal to activate the contactor. The signal closes the welding current path from the cable to the conductor block, making the gun electrically “HOT”. The cold inch switch allows the user to feed wire without closing the contactor. In this manner, the electrode wire can be fed through the gun with the gun tip electrically “COLD”. See Figure E.4.

GAS SOLENOID

Early Models Only (Below 10500)

The gas solenoid feature permits the LN-25™ to be used for gas metal arc welding (GMAW) processes. When the gun trigger circuit is activated, the control board signals the solenoid PC board to activate the gas solenoid, which allows shielding gas to flow through the gun to the arc.

Later Models Only (Above 10500)

The solenoid PC board circuitry has been added to the Control board and the solenoid PC board has been eliminated.

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LATER MODELS

Codes above 11144 have the Contactor circuitry added to the Control Board and the Contactor PC Board has been eliminated. Older codes that have been upgraded to the newew PControl Board may have had the Contactor PC Board removed

NOTE: Unshaded areas of block logic diagrams are the subject of discussion.

LN-25™