Lincoln Electric POWER MIG SVM167-A - Manual (Page 32)

THEORY OF OPERATION E-2 E-2
POWER MIG® 215
FIGURE E.2 – INPUT POWER CIRCUIT.
INPUT LINE VOLTAGE, MAIN
TRANSFORMER, VOLTAGE
SELECTOR SWITCH AND
BAFFLE MOUNTED DIODE
BRIDGE
The single phase input power is connected to
the POWER MIG® 215 through a line switch
located on the front panel.
A reconnect panel allows the user to configure
the machine for the desired input voltage. The
AC input voltage is applied to the primary of the
main transformer. The cooling fan motor
(120VAC) is powered from a portion of the
primary winding. For welding purposes, the
main transformer converts the high voltage, low
current input power to a low voltage, high current
output. This tapped secondary winding is
coupled to a voltage selector switch. By
selecting one of seven positions on the switch
the user can preset the desired voltage output
from a minimum setting (A) to a maximum
voltage setting (G). In addition, the main
transformer also has a 28VAC winding. This
28VAC is rectified at the baffle mounted diode
bridge. The resultant DC voltage (approx.
35VDC) is used to power the electronics on the
control board.
NOTE: Unshaded areas of block logic diagrams are the subject of discussion.
LINE
SWITCH
RECONNECT
PANEL
FAN
MOTOR RECTIFIER
DIODE
BRIDGE
CONTROL BOARD
GAS
SOLENOID
WIRE
SPEED
CONTROL
WIRE
DRIVE
MOTOR
TACH
GUN TRIGGER
+
-
OUTPUT DIODE
BRIDGE
+
-
NEGATIVE
TERMINAL
CONTACTOR
CONT
ACT
OR
CONTROL
TAP SELECTOR
SWITCH
OUTPUT
CHOKE POSITIVE
TERMINAL
TRANSFORMER
THERMOSTAT OUTPUT BRIDGE
THERMOSTAT
28 V
AC
MAIN
TRANSFORMER
OUTPUT
CAPACITORS
GUN
ASSEMBLY
Return
to
Section
T
OC
Return
to
Section
T
OC
Return
to
Section
T
OC
Return
to
Section
T
OC
Return
to
Master
T
OC
Return
to
Master
T
OC
Return
to
Master
T
OC
Return
to
Master
T
OC