Lincoln Electric SVM140-A service manual Table of Contents Theory of Operation Section

Return to Master TOC

Return to Master TOC

Return to Master TOC

Return to Master TOC

Section E-1Section E-1

TABLE OF CONTENTS

-THEORY OF OPERATION SECTION-

Theory of Operation	Section E
General Description	E-2
Input Line Voltage, Contactor and Main Transformer	E-2
Precharge and Protection	E-3
Main Transformer	E-4
Output Board and Torch	E-5
Control and Display Boards	E-6
Protection Circuits	E-7
Overload Protection	E-7
Thermal Protection	E-7
Insulated Gate Bipolar Transistor (IGBT) Operation	E-8
Pulse Width Modulation (PWM)	E-9

FIGURE E.1 – PRO-CUT 55 BLOCK LOGIC DIAGRAM

										WORK
										NOZZLE
			POWER BOARD						ELECTRODE
							MAIN			TORCH
			CR 1				TRANSFORMER	OUTPUT BOARD		CONNECTOR
			RELAY
										E
INPUT			IGBT							L
LINE	INPUT									E
										C
SWITCH	RECTIFIER									T
										R
			CAPACITOR							O
										D
									CHOKE	E
		R								S
		E	IGBT					PILOT		O
		C						TRANSISTOR		L
										E
		O
										N
		N
		N								O
		E								I
										D
		C	IGBT
		T
					CURRENT
		S			TRANSFORMER				TRIGGER & SAFETY
		W
		I	CAPACITOR							AIR
		T
		C								SOLENOID
		H
			IGBT
	AIR	P					TRIGGER & SAFETY
		R
	PRESSURE	O
	SWITCH	T	CR 1	IGBT
	"A"	E	RELAY
		C	DRIVE	GATE
		T		SIGNALS
			SIGNAL				ELECTRODE & TRANSFER
	L	I
		O					CURRENT FEEDBACK
	E	N	SIGNAL
							PILOT ENABLE
	A			CONTROL BOARD			ELECTRODE SOLENOID ENABLE
	D
							AIR SOLENOID ENABLE
			18/36VAC
				R	A	T	S
				E	I	H	A
			THERMOSTATS		R	E	F
				A
					L	R	E
				D		M	T
				Y	O	A	Y
FAN					W	L
			OUTPUT
MOTORS
			CONTROL
				DISPLAY BOARD
								12VAC
									24VAC

AUXILIARY

TRANSFORMER

PRO-CUT 55