Lincoln Electric RANGER 3PHASE SVM207-A Service Manual page 38

E-4
STARTER
SHUTOFF
SOLENOID
SOLENOID
STARTER
ENGINE
FLYWHEEL ALTERNATOR/
VOLTAGE REGULATOR
OIL
4
PRESSURE
1 SWITCH
ENGINE
3
CONTROL
SWITCH*
2
-
+
HOUR
METER
BATTERY
WELD CIRCUITRY
One end of the Weld Winding is connected to the
Output Rectifier and at the other end to the Reactor.
There are taps (C1) for constant voltage (CV) welding
and (WAC) for AC welding.
The Reactor Winding is tapped winding to provide the
three constant current (CC) welding ranges. As current
is drawn through the reactor it causes the voltage out-
put of the machine to drop off. This action creates the
"drooping" output characteristic that is required for stick
and TIG welding. The C1 tap does not go through the
reactor so there is very little "droop" as the weld current
is increased. It is used to provide the constant voltage
(CV) output that is required for wire welding.
The Polarity Switch is used to select the desired weld
mode — DC+, DC- or AC. It connects either the AC out-
put or the proper side of the rectified output to the
WORK and ELECTRODE terminals.
THEORY OF OPERATION
FIGURE E.2 - WELD CIRCUITRY
FUEL
MECHANICAL
ROTAT ION
SLIP
RINGS
IDLER
SOLENOID
FLASHING
DIODE
FIELD
CAPACITOR
OUTPUT
CONTROL
PRINTED CIRCUIT
BOARD
NOTE: Unshaded areas of Block Logic
Diagram are the subject of discussion
RANGER® 3 PHASE
RANGE
SWITCH
254
E
S2
AC
REACTOR
OUTPUT
BRIDGE
AC
W2 W1
C1
WAC
WELD WINDINGS
Z
STATOR
ROTOR
EXCITER
WINDING
7 9
3 6 X
TOROID TOROID
120 & 230 VOLT
BREAKERS AND
RECEPTACLES
*
Lead 254 - 1 turn through the toroid
Leads 3 & 6 - two turns through the toroid in opposite directions.
Lead X passes though the toroid in the same direction as lead 6
In AC weld mode, the weld current is routed through
another winding in the Reactor (S2 to E) in order to
improve weld characteristics.
When DC output is selected, the AC weld current is fed
to the Output Rectifier to be converted to DC. The
positve output of the rectifier is then routed through the
Choke to smooth out the ripple and provide good weld-
ing characteristics.
Lead #254 is a sense lead that is connected in parallel
to the lead from the Range Switch to the AC side of the
rectifier and as a result shares a portion of the weld cur-
rent. It is routed through the toroid to activate the Idler
Circuit when weld current is present.
* *
TOROID TOROID
ELECTRODE
TERMINAL
+
CHOKE POLARITY
SWITCH
--
TERMINAL
AUXILIARY
WINDINGS
Y
3
5
6
X
* *
Z X Y
480 VOLT 3 PHASE
BREAKER AND
RECEPTACLE
E-4
WORK