Lincoln Electric LN-9 SVM127-A - Manual (Page 53)

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Section E-1 Section E-1
LN-9 Wire Feeder
Theory of Operation ............................................................................................................. Section E
General Description ...............................................................................................................E-2
Power Input Circuits...............................................................................................................E-2
Trigger and Shutdown Circuit ................................................................................................E-3
Arc Voltage, Wire Speed Control and Metering.....................................................................E-4
Printed Circuit Board Functions.............................................................................................E-5
TABLE OF CONTENTS
-THEORY OF OPERATION SECTION-
INPUT
CONNECTOR
TO
VOLTAGE
BOARD
TO
CONTROL
BOARD
METER
BOARD
VOLTS
SPEED
SWITCH
T1
CIRCUIT
BREAKER
R1
TRIGGER
CONNECTOR
TRIGGER
BOARD
F
U
S
E
T2
WIRE FEED
MOTOR
THERMOSTAT
C
O
N
T
R
O
L
B
O
A
R
D
VOLTAGE
BOARD
P
O
W
E
R
B
O
A
R
D
GROUND
LEAD
PROTECTOR
WIRE
FEED
MOTOR TACH
BOARD
WIRE
SPEED
CONTROL
VOLTAGE
CONTROL
POLARITY
SWITCH
VOLTAGE SENSING
VOLTAGE CONTROL
POWER SOURCE OUTPUT TRIGGER (#2 &#4)
S
H
U
T
D
O
W
N
+ 15VDC
+ 15VDC
WIRE SPEED CONTROL
GEAR
BOX
TRIGGER SIGNAL
TRIGGER SIGNAL
R
E
F
E
R
E
N
C
E V
O
L
T
A
G
E
WORK
ELECTRODE VOLTAGE SENSING
24VAC
28VAC 10VAC
FIGURE E.1 – LN-9 BLOCK LOGIC DIAGRAM