ESAB LTR 160, Руководство по обслуживанию

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cltr0de2
9 Arc voltage sensing
Machines with shunt signal amplifier: The arc voltage from RS01 is connected to
AP01 through AP10. The resistors R172 and R177, with the value 0
Ω
, are
mounted. The capacitors C52 and C95 are not mounted on the board.
Machines without shunt signal amplifier: The arc voltage from RS01 is
connected directly to AP01. The resistors R172 and R177 are not mounted. The
capacitors C52 and C95 are mounted on the board.
The arc voltage signal limits the open--circuit voltage and is also used to sense the
start of welding. During TIG welding, the arc voltage can vary between 5 and 45 V.
The following description describes the starting sequence for the various welding
modes:
MMA
1. Open--circuit voltage control.
Open--circuit voltage LTR 160: 65--80 V; LTR 200: 72--82 V.
2. A voltage less than 45 V is interpreted as a welding start. The control amplifier
generates an elevated starting current for about 300 ms.
The starting current is 75% higher than the set value of current when the set
value is 25 A. The starting current is 25% higher than the set value of current
when the set value is 160 A.
3. Welding is performed at the set value of current.
TIG, HF START
1. Gas pre--flow.
2. The starting voltage is about 100 V, and HF ignition is provided for a maximum
of 0.5 seconds.
3. A voltage less than 45 V is interpreted as a welding start. The control amplifier
generates an elevated starting current for about 50 ms.
The starting current is 20 A higher than the set value of current.
4. Welding is performed at the set value of current.
TIG, LIFTARC START