Lincoln Electric SVM149-A service manual Table of Contents Theory of Operation Section

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Section E-1 Section E-1

TABLE OF CONTENTS

-THEORY OF OPERATION SECTION-

Theory of Operation	Section E
General Description	E-2
Input Line Voltage and Auxiliary Transformer	E-2
Precharge and Protection	E-3
Main Transformer	E-4
Output Section and Torch	E-5
Control Board	E-6
Protection Circuits	E-7
Overload Protection	E-7
Thermal Protection	E-7
Accidental Operation Protection	E-7
Safety Parts-In-Place Protection	E-7
Insulated Gate Bipolar Transistor (IGBT) Operation	E-8

FIGURE E.1 – PRO-CUT 25 BLOCK LOGIC DIAGRAM

INPUT 115/230/1/50/60 VAC

L1 SW1 A 300uH

B

RL3		RL2
R1		RL2
10/10W
	F1
1A/250V		RL2

C26

AC	AC
CP	CP	CP
CP	CP
AC	AC

R1

CP

R2

15K/3W 15K/3W

1500uF/250V

+

C1a,b

+

C2a,b

Q1a,b,c	D10	Lout	BS1
IRG4BC30W				WRK
		240uH	8A
T2	SEC		+12VDC TRANSFER
PRI
C12	D11		RL1	NZL (2)
			C14

WORK CLAMP

V1

RL2

RL1

	R24
Q2a,b,c	6 . 8k/5W
IRG4BC30W

FN1 230VAC V2

115VAC

L1

T1

230V

RL1

1500uF/250V

	SHUNT		EL (3)
C13	SH-	SH+

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NO COM NC

Purge Switch

115V

L1

Input

Voltage Board

12VDC

Air

Solenoid

1

CN1	15VAC				CN2													CN3
1					9													1
2	15VAC				10													2
3	SAFETY				5													3
4	+28VDC				6													4
5	SEC GND				3													Main Inverter Board
6	OVLOAD				22
7	115/230				2
8	+12VDC				20										CN1
					15 16 12 18 14 1													4
								11 4		13 7		19 24 21 23 8		17	1	2	3
	PS2	PS1	SEC GND OVLOAD	SAFETY	V+ EV1 +15Vrms	+12VDC	+8V SW +12VDC SW	SEC GND	OVLOAD	TRANSFER SW	TRANSFER	SOL 1 DRIVER	V OUT OUTPUT TRIGGER SOL 2 DRIVER		POT WIPER	POT CW	POT CCW
CN1	8	6	17 9	3	1	2	18 14 7		15 4		11 5		16 10 12 13		23 22 24

Display LED's

Output Control

Control Board

PT

12VDC Solenoid 2

PRO-CUT 25