Lincoln Electric SVM 106-A service manual Theory of Operation, Trigger Circuit

		THEORY OF OPERATION					E-3
TOCSectionto	TOCMasterto	FIGURE E.2 – TRIGGER CIRCUIT.
Return	Return		OPTIONAL		GAS	OPTIONAL
						TIMER OR
			METER KIT		SOLENOID
						BURNBACK KIT
				115 VAC

								SCR	CURRENT	5-95 VDC
										WIRE DRIVE
								POWER	LIMITING
										MOTOR
								CIRCUIT	CIRCUIT
TOC	TOC				8.8 VAC
			CIRCUIT	TRIGGER				115 VAC	CONTROL
			BREAKER	TRANS-
									BOARD
				FORMER
to Section	to Master	FROM			24 VAC	DIODE
			115 VAC					CR1
		WELDING				RECTIFIER	24 VDC
										TO WELDING
		POWER				NETWORK		CONTROL
										CONTACTOR
		SUPPLY						RELAY
Return	Return									GUN
										TRIGGER
						WIRE		GROUND
						SPEED		LEAD
						CONTROL		PROTECTOR

TOC	TOC
Section	Master	TRIGGER CIRCUIT	pulled, a circuit is closed which energizes the
		The 24 VAC output of the trigger transformer	control relay. The three sets of contacts in
to	to		the relay close and energize the multiple
		is sent to the control PC board and rectified	functions of the wire feeder. See Figure E.2.
Return	Return
		by a diode network. When the gun trigger is

to Section TOC	to Master TOC
Return	Return	NOTE: Unshaded areas of block logic diagrams are the subject of discussion.

LN-7 GMA WIRE FEEDER