Lincoln Electric IDEALARC R3R-300 Service Manual page 29

Section E-1
- THEORY OF OPERATION SECTION -
Theory of Operation .............................................................................................................Section E
General Description ....................................................................................................................E-2
Input Line Voltage, Contactor and Main Transformer.................................................................E-2
Output Mode and Control, Rectification and Feedback ............................................................E-3
Optional Polarity Switch and Amptrol Circuits ...........................................................................E-4
Protective Devices and Circuits..................................................................................................E-5
SCR Operation ............................................................................................................................E-6
CONTROL
TRANSFORMER
MOTOR
POWER
THERMOSTATS SWITCH
R
E
C
O
N
N
E
C
T
INPUT
CONTACTOR
TABLE OF CONTENTS
OPTIONAL
OPTIONAL
POCKET
POCKET
AMPTROL
AMPTROL
TRANSFORMER
PC BOARD
AMPHENOL
TERMINAL
STRIP
REMOTE
SWITCH
FAN
MAIN
TRANSFORMER
FIGURE E.1 - IDEALARC R3R BLOCK LOGIC DIAGRAM
IDEALARC R3R
OUTPUT
CONTROL
DIAL
ARC FORCE
SELECTOR
CONTROL
SWITCH
CONTROL BOARD
G S
A I
G
T
N
E
A
L
S
SNUBBER
BOARD
SHUNT
SCR DIODE /
HYBRID BRIDGE
Section E-1
FEEDBACK
OPTIONAL
POLARITY
F
SWITCH
OUTPUT
E
E
CHOKE
D
B
A
C
K
TERMINAL
NEGATIVE
OUTPUT
TERMINAL
POSITIVE
OUTPUT