Lincoln Electric SVM144-B service manual Theory of Operation Section, Section E

	Section E-1		TABLE OF CONTENTS	Section E-1
Master TOC			- THEORY OF OPERATION SECTION -
		Theory of Operation		Section E
to
Return			Input Line Voltage and Main Transformer	E-2
			Output Rectification and Feedback Control	E-3
			Constant Voltage Output	E-4
			Wire Drive Motor and Feedback	E-5
			Thermal and Overload Protection	E-6
			Overcurrent Protection	E-6
TOC			Wire Feed Overload Protection	E-6
			SCR Operation	E-7
Return to Master			FIGURE E.1 – BLOCK LOGIC DIAGRAM

		GAS	FAN
		SOLENOID	MOTOR		WIRE
					DRIVE
	WIRE				MOTOR
	SPEED
	ARC	CONTROL
	VOLTAGE	BOARD
					TACH
TOC	115 VAC					GUN TRIGGER
		RECTIFIER
Master		DIODE	G			FEEDBACK
		BRIDGE
			A
	30 VAC		T
			E
		SNUBBER
to	LINE		S
		BOARD
Return	SWITCH		I
			G
			N
			A
			L
			POWER	C	F	OUTPUT	POSITIVE
	RECONNECT		ENHANCEMENT	A		CHOKE
							TERMINAL
	MAIN		CHOKE	P	E
	TRANSFORMER			A	E
		SCR		C	D
		RECTIFIER		I	B
				T	A
				O	C		NEGATIVE
				R	K
							TERMINAL
TOC				S
				SHUNT
Return to Master		POWER MIG 255