Section e theory of operation, Return to master toc – Lincoln Electric SQUARE WAVE TIG 255 SVM100-A User Manual
Page 33
SQUARE WAVE TIG 255
Input Line Voltage and Main Transformer .......................................................E-1
Output Rectification and Feedback Control ....................................................E-2
High Voltage / High Frequency Circuit ............................................................E-3
DC Welding Output .........................................................................................E-4
AC Welding Output .........................................................................................E-5
SCR Operation .......................................................................................................E-6
Thermal Protection .................................................................................................E-7
Section E
TABLE OF CONTENTS
- THEORY OF OPERATION SECTION -
LINE
SWITCH
R
E
C
O
N
N
E
C
T
MAIN
TRANSFORMER
X2
X1
POWER
FACTOR
CAPACITORS
FAN
115VAC
PROTECTION
SNUBBER
BOARD
ARC START
115 VAC
GATE SIGNALS
HI-FREQ
115 VAC
CONTROL
BOARD
LCD DISPLAY
KEYPAD
LED
BOARD
KEYPAD
HIGH VOLTAGE
TRANSFORMER
CIRCUIT
115 VAC
115 VAC
REMOTE
RECEPTACLE
115 VAC
RECEPTACLE
CONTROL
TRANSFORMER
24 VAC
18 VAC
16 VAC
HIGH FREQUENCY SPARK
WORK
ELECTRODE
HI-FREQ
TRANSFORMER
BY-PASS
BOARD
POLARITY
SWITCH
CHOKE
FEED BACK
GATE SIGNALS
AC
AC
DC+
DC-
SCR
BRIDGE
SHUNT
POWER SUPPLY BLOCK LOGIC DIAGRAM
NOTE: On subsequent pages areas of this diagram that are the topic of discusstion are shown in white, other
portions of the circuit are shaded.