Lincoln Electric SVM136-A service manual Table of Contents Theory of Operation Section

	Section E-1		Section E-1
TOC		TABLE OF CONTENTS
		-THEORY OF OPERATION SECTION-
to Master		Theory of Operation	Section E
		General Description	E-1
Return		Input Line Voltage, Contactor and Main Transformer	E-2
		Output Control, Rectification and Feedback	E-3
		Protective Devices and Circuits	E-4
		SCR Operation	E-5

FIGURE E.1 – BLOCK LOGIC DIAGRAM

TOC						OUTPUT
						CONTROL
	CONTROL
	TRANSFORMER
Master
						CONTROL BOARD			NEGATIVE
									OUTPUT
						G	S	F	TERMINAL
to								E
						A	I
	POWER							E
						T	G	D
Return	SWITCH				MAIN	E	N	B
			TRANSFORMER				A	A
							L	C
							S	K
			R						F
			E						E
			C						E
									D
			O						B
			N						A
									C
			N					OUTPUT	K
			E				CAPACITORS		POSITIVE
			C
			T						OUTPUT
									TERMINAL
	INPUT					SCR / DIODE			SHUNT
	CONTACTOR					HYBRID BRIDGE
TOC
Master			T		115VAC
	TO	REMOTE	E	S
		CONTROL	R	T
	CONTROL		M
				R
	BOARD		I			FAN
to			N	I
				P
			A
			L	s	42VAC
Return
	14 PIN AMPHENOL

GENERAL DESCRIPTION

	The CV-400 is an SCR controlled three-phase DC
	power source. It is designed for all open arc constant
TOC	voltage (CV) processes within the capacity of the
	machine. The output characteristics have been opti-
MastertoReturn	mized for CV processes without the use of a variable
	arc control. Minimum to maximum output is obtained
	with a single potentiometer control.
	IDEALARC CV-400