Theory of operation, Input line voltage and main transformer, E-1 wire-matic 255 – Lincoln Electric WIRE-MATIC 255 SVM 119-A Manuel d'utilisation
Page 44
E-1
THEORY OF OPERATION
E-1
WIRE-MATIC 255
INPUT LINE VOLTAGE AND MAIN
TRANSFORMER
The desired single phase input power is connected to
the WIRE-MATIC 255 through a line switch located on
the front panel.
A reconnect panel allows the user to configure the
machine for the desired input voltage. This AC input
voltage is applied to the primary of the main trans-
former and to the thermostatically controlled fan
motors. The transformer changes the high voltage, low
current input power to a low voltage, high current out-
put. In addition, the main transformer also has an iso-
lated center tapped 30 VAC auxiliary winding that sup-
plies power to the Control Board for SCR gate drive
and gas solenoid operation. The weld power windings
connect to the Control Board as well as to the main
SCR Rectifier.
Figure E.2 - Input Line Voltage and Main Transformer.
INPUT LINE VOLTAGE AND MAIN TRANSFORMER
LINE
SWITCH
MAIN
TRANSFORMER
RECONNECT
FAN
MOTORS
SCR
RECTIFIER
C
A
P
A
C
I
T
O
R
S
SHUNT
CHOKE
WIRE
DRIVE
MOTOR
TACH
POSITIVE
TERMINAL
NEGATIVE
TERMINAL
GAS
SOLENOID
WIRE
SPEED
ARC
VOLTAGE
CONTROL BOARD
FEEDBACK
GUN TRIGGER AND THUMB SWITCH
F
E
E
D
B
A
C
K
G
A
T
E
I
G
N
S
A
L
NOTE: Unshaded areas of Block Logic
Diagram are the subject of discussion