Lincoln Electric LN-25 PRO DUAL POWER Service Manual page 47

E-5
ELECTRODE
INPUT
INPUT
21
14 PIN AMPHENOL
REMOTE
VOLTAGE
TRIGGER CIRCUIT
Several When the gun trigger is closed, the control
board is signaled to apply armature voltage to the drive
motor and to activate any auxiliary circuits that may be
incorporated within the LN-25™ PRO DUAL POWER.
Trigger interlock is used for long welds. When an arc
is established the trigger can be released. To stop
welding, the gun trigger is pulled again, and when it is
released the welding power source output turns off and
the wire speed stops.
THEORY OF OPERATION
FIGURE E.5 - TRIGGER CIRCUIT
CURRENT TRANSDUCER
CONTACTOR
SOLENOID POLARITY
SP1
CONTROL BOARD
POWER
SUPPLY
COLD CC
FEED CV
RUN IN
NOTE: Unshaded areas of Block Logic
Diagram are the subject of discussion
LN-25™ PRO DUAL POWER
67
TIMER OPTION
MOTOR
MOTOR
OVERLOAD
ARMATURE
TACH FEEDBACK
GUN TRIGGER
TRIGGER
GAS
INTERLOCK
PURGE
E-5
FEEDPLATE
TACH
GUN
WIRE
SPEED