Theory Of Operation - Lincoln Electric RANGER 3PHASE SVM207-A Service Manual

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FIGURE E.2 - ROTOR, STATOR AND CONTROL CIRCUITS
FUEL
STARTER
SHUTOFF
SOLENOID
SOLENOID
STARTER
ENGINE
FLYWHEEL ALTERNATOR/
VOLTAGE REGULATOR
OIL
4
PRESSURE
1 SWITCH
ENGINE
3
CONTROL
SWITCH*
2
-
+
HOUR
METER
BATTERY
ROTOR, STATOR & CONTROL CIRCUITS
Once the Engine is running and the oil pressure switch
closes, 12 VDC is fed to the rotor slip rings by way of
the Control PC Board. This "flashing" voltage energizes
the rotor and the resulting spinning magnetic field
induces power into the windings of the stator. The
exciter winding voltage is routed to the Control Board
where it is rectified and regulated and fed back to the
rotor slip rings. . This regulated supply is used to control
the voltage output of the welder. A diode on the PC
Board is used to isolate the exciter voltage from the
engine 12 VDC supply. The Output Control is used to
adjust the weld voltage.
The Idler Circuit is also controlled by the Control PC
Board. A Toroid is used to sense current draw through
either the weld circuit or any of the auxiliary receptacles.
When current is sensed, a signal from the Toroid caus-
es the PC Board to release the Idler Solenoid and the
engine goes to high speed.

THEORY OF OPERATION

REACTOR
W2
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
OUTPUT
BRIDGE
AC
--
C1 W1
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
Approximately 10 seconds after the current stops, the
board will re-energize the solenoid and pull the engine
down to the low idle speed. If the Control Power Switch
is in the High Idle position, the signal from the Toroid is
ignored.
The Weld Winding provides the power for welding.
Different portions are used depending on the weld
mode selected. The full winding is used for DC welding
while a tapped off portion (WAC) is used for AC welding.
There is also a tap (C1) used for constant voltage (CV)
welding. The Auxiliary Winding is a 3 phase 'wye' con-
nected 480 VAC supply. Tapped off of one leg are the
230 VAC single phase and the 120VAC single phase
supplies for the various receptacles. Each of the recep-
tacles including the 3 phase receptacle is protected by
an appropriately sized Circuit Breaker.
* *
TOROID TOROID
ELECTRODE
TERMINAL
+
CHOKE POLARITY
SWITCH
WORK
TERMINAL
AUXILIARY
WINDINGS
Y
3
5
6
X
* *
Z X Y
480 VOLT 3 PHASE
BREAKER AND
RECEPTACLE
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