ESAB LHF 405 PIPEWELD, Service Manual

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Edition 071024
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WIRING DIAGRAM, LHF 405 PIPEWELD
Component description
WARNING !
STATIC ELECTRICITY can damage circuit
boards and electronic components.
SSSS
Observe precautions for handling electrostatic
sensitive devices.
SSSS
Use proper static--proof bags and boxes.
ESD
B1
Thermal switch: breaks at 68 _ C, resets at 59 _ C; fitted on the thyristor
heatsink
B2
Thermal switch: breaks at 160
_
C
C1
Capacitor 2 µ F, for cooling fan
C2,C3
Capacitor 0,1
µ
F
H1
Indicating lamp, white
H2
LED, yellow; on when thermal overload is activated, i.e. when one or both
of thermal switcjes B1 and B2 are open
L
Inductor
LH20/1
Circuit board
M1
Fan
Q01
Mains switch
R01
Potentiometer 2k Ω, for controling the welding current
R03
Potentiometer 10k Ω, for ARC FORCE
R1
Base current resistor, 100
Ω
RB
Shunt, 120mV@400A
S1
Selector switch, MMA/Air--Arc Gouging
T1
Main transformer
T2
Control transformer, supplied at 35V from X45, secondary 19V supplies
circuit board LH20/1
V1,V3,V5
Main diodes
V2,V4,V6
Main thyristors