High Voltage / High Frequency Circuit - Lincoln Electric SQUARE WAVE TIG 255 SVM100-A Service Manual

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HIGH VOLTAGE / HIGH FREQUENCY CIRCUIT

LINE
MAIN
SWITCH
TRANSFORMER
R
E
C
O
N
N
E
C
T
POWER
FACTOR
CAPACITORS
115VAC
FAN
115 VAC
RECEPTACLE
RECEPTACLE
The control board passes the 115vac through the pro-
tection / snubber board to the primary of the high volt-
age transformer. The secondary of the high voltage
transformer is coupled to a spark gap generator and
also to the high frequency transformer. The high fre-
quency transformer transfers the high frequency
"spark" to the electrode stud.
SQUARE WAVE TIG 255
THEORY OF OPERATION
POLARITY
SWITCH
DC+
AC
X2
SCR
BRIDGE
X1
AC
DC-
ARC START
115 VAC
PROTECTION
SNUBBER
GATE SIGNALS
BOARD
HI-FREQ
115 VAC
CONTROL
TRANSFORMER
115 VAC
REMOTE
BY-PASS
BOARD
SHUNT
CHOKE
LCD DISPLAY
CONTROL
BOARD
24 VAC
18 VAC
16 VAC
HIGH VOLTAGE
HIGH FREQUENCY SPARK
TRANSFORMER
CIRCUIT
WORK
HI-FREQ
TRANSFORMER
ELECTRODE
KEYPAD
LED
BOARD
KEYPAD