ESAB | LTN 255 | Service manual | ESAB LTN 255 User manual

ESAB LTN 255 User manual
LTN 255
Aristotig 255
Service manual
0740 800 116
040820
Valid for serial no. 745--xxx--xxxx to 011--xxx--xxxx
LIST OF CONTENTS
Page
READ THIS FIRST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
COMPONENT DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CONNECTION DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AP01 DESCRIPTION OF OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1 Power supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 Power supply monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3 Start / Stop input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4 Remote control input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5 Shunt input with amplifier AP10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6 Arc voltage monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7 HF generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8 Gas valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9 Machine type indicator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10 Thermal overload cutout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11 Welding process control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Hot start MMA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12 Control panel interface circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13 Pulse width modulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14 Gate circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Checking the gate pulses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Component positions, circuit board AP01 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TRANSISTOR BOARD AP02 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TRANSISTOR BOARD AP03 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MOS TESTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SOFT STARTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CONTROL PANEL AP05 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DISPLAY BOARD AP06 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AP07 SUPPRESSION BOARD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SUPPRESSION BOARD AP08 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SUPPRESSION BOARD AP09 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
FAULT CODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DISASSEMBLY / REASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fitting the diode modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Removal of transistor circuit boards AP02 and AP03 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Refitting the transistor circuit board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fitting the main transformer TC02 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TECHNICAL DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LOAD CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Control panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Other functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SPARE PARTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
NOTES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rights reserved to alter specifications without notice.
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48
READ THIS FIRST
Maintenance and repair work should be performed by an experienced person, and electrical
work only by a trained electrician. Use only recommended replacement parts.
This service manual is intended for use by technicians with electrical/electronic training for
help in connection with fault--tracing and repair.
Use the wiring diagram as a form of index for the description of operation. The circuit
board is divided into numbered blocks, which are described individually in more detail in
the description of operation. All component names in the wiring diagram are listed in the
component description.
This manual contains details of all design changes that have been made up to and including
August 2004.
The LTN 255 is designed and tested in accordance with international and European
standard IEC/EN 60974--1 and EN 50199.
On completion of service or repair work, it is the responsibility of the person(s) etc.
performing the work to ensure that the product does not depart from the requirements
of the above standard.
WARNING
ARC WELDING AND CUTTING CAN BE INJURIOUS TO YOURSELF AND OTHERS. TAKE PRECAUTIONS WHEN WELDING. ASK FOR YOUR EMPLOYER’S SAFETY PRACTICES WHICH SHOULD BE
BASED ON MANUFACTURERS’ HAZARD DATA.
ELECTRIC SHOCK -- Can kill
S
Install and earth the welding unit in accordance with applicable standards.
S
Do not touch live electrical parts or electrodes with bare skin, wet gloves or wet clothing.
S
Insulate yourself from earth and the workpiece.
S
Ensure your working stance is safe.
FUMES AND GASES -- Can be dangerous to health
S
Keep your head out of the fumes.
S
Use ventilation, extraction at the arc, or both, to keep fumes and gases from your breathing zone and
the general area.
ARC RAYS -- Can injure eyes and burn skin.
S
Protect your eyes and body. Use the correct welding screen and filter lens and wear protective
clothing.
S
Protect bystanders with suitable screens or curtains.
FIRE HAZARD
S
Sparks (spatter) can cause fire. Make sure therefore that there are no inflammable materials nearby.
NOISE -- Excessive noise can damage hearing
S
Protect your ears. Use ear defenders or other hearing protection.
S
Warn bystanders of the risk.
MALFUNCTION -- Call for expert assistance in the event of malfunction.
READ AND UNDERSTAND THE INSTRUCTION MANUAL BEFORE INSTALLING OR OPERATING.
PROTECT YOURSELF AND OTHERS!
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COMPONENT DESCRIPTION
This component description refers to the wiring diagram on page 8.
The LTN 255 is a primary--switched power unit, using parallel--connected MOSFET--transistors as the switching elements. The switching frequency is 48.5 kHz. The conducting
interval varies between zero and 9.5µs, depending on the welding current output. The
conducting time and frequency are controlled by circuit board AP01.
WARNING !
STATIC ELECTRICITY can damage circuit
boards and electronic components.
ESD
S
Observe precautions for handling electrostatic
sensitive devices.
S
Use proper static--proof bags and boxes.
AP01
The main circuit board with control electronics. See description on page 10.
AP02
Circuit board with power transistors for the positive pole,
see description on page 22.
WARNING! the transistors are connected to mains voltage potential.
AP03
Circuit board with power transistors for the negative pole,
see description on page 24.
WARNING! the transistors are connected to mains voltage potential.
AP05
Circuit board control panel. The circuit diagram is shown on page 28.
AP06
Display driver board with pulse generator. The circuit diagram is shown on
page 30.
AP07
Interference suppression circuit board: see the circuit diagram on page 31.
AP08
Interference suppression circuit board. Prevents mains--borne interference.
The circuit diagram is shown on page 32.
AP09
Interference suppression circuit board, remote control connector, see the
diagram on page 33.
AP10
Circuit board shunt amplifier, see description on page 13.
AP11
HF generator.
C01
Capacitor, 0.1µF, 1000V DC, transient protection.
C02, C03
Capacitors, 1000µF, buffer/smoothing capacitors.
Time to discharge after turning off the unit: about two minutes.
C04
Decoupling capacitor, 0.1µF, 1000V DC, protects against HF.
C05
2 -- capacitors, 4.7µF, see L02.
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C06 -- C09
Capacitor, 0.1µF, 400V DC.
C10, C11
Capacitors, 1nF. Protection against transient voltages.
C13 -- C15
Capacitors, 10nF. Protection against transient voltages. The capacitors are
only used together with an old version of circuit board AP08, see page 32.
EV01
Fan, 24V DC, cooling the power components.
EV02
Fan, 24V DC, cooling AP11 and TV01.
HL01
Lamp, 28V, white, lights when mains power is on.
L01
Secondary inductor.
L02
Inductor, forms an LC circuit with C05 and V06 to reduce the risk of arc
extinction at low welding currents.
When V03 conducts, the LC circuit charges up. The circuit is capable of
temporarily maintaining a high arc voltage at low current, thus reducing the
risk of arc extinction.
Diode V06 prevents capacitor C05 from going negative.
L03
Ferrite ring core, transient protection.
L04
Ferrite ring core, transient protection.
L05
Ferrite ring core, transient protection.
QF01
Mains power supply switch, 3--pole.
R01
Resistor, 3.9kΩ 5W.
R02
Resistor, 8.2kΩ 5W.
RS01
Shunt, 119mV ±1mV at 250A
ST01
Thermal overload cutout, for overload protection, mounted on the welding
inductor winding (L01). Breaks at 130 _C and resets at 100 _C
TC01
Control power transformer. The primary is supplied at 400V, with
secondary output voltages of 9, 20, 26 and 42V.
Fuses are mounted on the control transformer. A number of machines
produced before week 719 have no fuses. There is no need to fit fuses to
those machines.
TC02
Main transformer. For fitting instructions, see page 38.
TV01
HF transformer.
V01, V02
Mains rectifier bridges, 35A, 1200V. After replacing the rectifier bridges,
the machine must be soft--started: see instructions on page 27.
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V03, V04
Rectifier and freewheel diodes.
V03 rectifies the welding current.
During the time interval between two voltage pulses from transformer
TC02, the freewheel diodes V04 maintain the welding current from inductor
L01.
On the cooling fins three diode modules are mounted. Each diode module
consists of two diodes. If one module is broken all modules have to be
replaced.
From serial number 011--148--xxxx a new diode module is used. The rated
current for the new module, SCOMES MKK300.4, is 300 A. The rated
current for the old module, Motorola MURP20040CT, is 200 A. Because of
the higher rating only two modules are needed for the rectifier unit. The
ordering no. for the new module is the same as for the old.
For installation instructions, see page 36.
V05
LED, yellow. Lights when thermal cutout ST01 operates (breaks) as a
result of high temperature.
V06
Diode, see L02.
X01 -- X03
Terminal block.
XP01
Pin connector with jumper. Connected when the machine is used without
water cooler.
XS . .
Sleeve connectors.
XS04
26--pole ribbon cable connector.
XS10
12--pole Burndy contact, for connection of remote control unit.
XS11
TIG central connector: only LTN 255 variant - 894.
XS12
2--pole Cannon connector, only LTN 255 variant - 895.
XS13
Welding current connector, OKC, only LTN 255 variant - 895.
XS14
Welding current terminals, (two), OKC type.
XS20
26--pole connector for ribbon cable.
XS24
Connection for 400V to water cooler. (The water cooler is an accessory,
which is mounted under the machine.)
XS25
Connection for water flow guard.
YV01
Solenoid valve.
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WIRING DIAGRAM
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1
POWER SUPPLY
8
GAS VALVE
2
POWER SUPPLY MONITORING
9
MACHINE TYPE SELECTION
3
START/STOP INPUT
10
THERMAL OVERLOAD SWITCH
4
REMOTE CONTROL INPUT
11
WELDING PROCESS CONTROL
5
SHUNT INPUT WITH AMPLIFIER AP10
12
INTERFACE CIRCUITS FOR CONTROL PANEL
6
ARC VOLTAGE SENSING
13
PULSE WIDTH MODULATOR
7
HF UNIT
14
GATE CIRCUIT
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AP01 DESCRIPTION OF OPERATION
This description refers to the wiring diagram on page 8 and to the components position
diagram on page 21.
Only those parts connected to the board’s inputs and outputs are described here. If the circuit
board is faulty, it must be replaced.
After replacing the circuit board, the machine must be soft--started. See the instructions
on page 27.
1
Power supply
The power supply to the board can be divided into three parts; a, b and c.
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The supply voltage from transformer TC01 is rectified and voltage regulator VR2
stabilises the supply to +5 ¦0.25V DC.
Resistors R126 and R127, capacitor C104 and diode D27 form a voltage monitoring
circuit for the unregulated supply to voltage regulator VR2.
The voltage from potential divider R126/R127 is connected to pin 9 of IC7: see 2)
below. The voltage is about 2.5V.
Voltage regulator VR4 supplies the fans EV01 and EV02 with +28V.
Voltage regulator VR3 produces a stabilised +15V supply, which is used to supply
the remote control unit. This supply is referred to as +15VB, and its neutral point,
0VB, is separated from the electronic neutral (0V). Potentiometer R122 is used to
adjust the voltage. See also 4) on page 12.
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Voltage regulator VR1 produces an output voltage of +20 ¦1.0V, which supplies the
pulse width modulator output stage (Block 13).
Potential divider R100/R101 supplies 2.6V to the processor in Block 11. This
provides a signal that the power supply is available.
The +27V unregulated DC power supply to VR1 also supplies relay RE1 in Block 7
and indicating lamp HL01 via resistor R120.
Zener diode D22 drops the voltage to +15V, and this, together with the --15V supply,
powers the analogue circuits. The processor monitors the - 15V supply by a signal
from resistor R54.
2
Power supply monitoring
IC7 and IC9 monitor the voltage of battery
BA1. The nominal battery voltage is 3V. If
it falls below 2.5V, the display shows error
message E06. Battery life is about five
years.
The machine also operates without battery,
but data stored in the welding data memory,
see page 46, disappears when the mains
voltage is switched off. At power up default
values will be read into the memory.
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A voltage of about 2.5V is supplied to IC7, pin 9, from power supply circuit 1a.
If this voltage drops below the threshold voltage of 1.3V, pin 10 of IC7 goes low,
providing the processor with a low power supply voltage signal. The processor then
” warning signal in the display and stores current data.
generates a ”
If the +5V supply to pin 3 of IC7 drops below 4.65V, pin 15 goes low and inhibits
the pulse width modulator in block 13. The processor receives a reset signal and
data in the RAM memory is protected by the backup battery power supply.
Pin 2 of IC7 supplies the RAM memory in Block 11 with power, both when the
machine is energised and when it is shut down.
When power to the machine is turned off, the display also shows ”
confirm that the processor has stored the current data.
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” to
3
Start / Stop input
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The output signal from IC14, pin 4, goes high (+5V) when the torch contact switch
is not activated, and low (0V) when it is activated.
4
Remote control input
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If the remote control input is activated, but there is no reference signal, resistor R72
holds the reference input low. This results in a welding current of 3A for TIG
welding and 4A for MMA welding.
The remote control unit plug must incorporate a link between pins L and M. When
the remote control unit is connected, the voltage at the cathode of diode D19 is 0V.
With the remote control unit removed, the voltage at the cathode of the diode is +5V.
When adjusting the +15VB voltage, link connections C3 and C4 and measure the
voltage at the cathode of diode D12. The voltage there must be 5.1 ¦0.05V. Adjust
the voltage by means of resistor R122: see circuit diagram 1b on page 10.
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5
Shunt input with amplifier AP10
Shunt amplifier circuit board AP10 is supplied with ¦15V via connections D1 and
D3 on circuit board AP01. At no--load voltage, the circuit board’s neutral voltage
(0V) is at the same potential as the welding circuit negative connection.
250A welding current produces 119mV ±1mV at the shunt. The signal from the
shunt is amplified by the shunt amplifier, so that a 119 mV input signal from the
shunt produces a 6.66V output signal. Resistors R10, R6 and R7 on circuit board
AP01 divide this voltage to 2.65V, which is then supplied to pin 3 of IC2.
IC2 is a buffer circuit. The processor receives a signal representing the welding
current from output pin 6 of IC2. Resistor R4 connects the shunt signal to the
control amplifier.
LTN 255 has different current setting resolutions in the TIG and MMA modes. In
the TIG mode, the welding current can be set in 1A steps, while in the MMA mode,
the current can be set in 2A steps. This means that the lowest current in the MMA
mode is 4A, while in the TIG mode it is 3A.
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Component positions, AP10
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6
Arc voltage monitoring
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This circuit measures and scales the arc voltage to a suitable level for the processor.
64V arc voltage produces a voltage signal of 5.1V at the cathode of diode D3.
Open--circuit voltage control
The arc voltage is connected to input D2 and supplied to potential divider R29 and
R30, the output from which is supplied to the voltage control circuit. The
open--circuit voltage must be about 70V.
7
HF generator
WARNING: Dangerous voltages in this circuit.
When the welding torch switch is operated, and the open--circuit arc voltage is over
50V, relay RE1 closes and turns on HF generator AP11. It remains activated for
0.75 seconds. If the arc has not struck within this time, the relay drops off.
The voltage on the primary side of HF transformer TV01 is about 400 V, and the
secondary voltage is about 8 kV.
From serial number xxx--006--xxxx a new type of HF generator is used,
0367 268 001. This generator produces about 500 V on the primary side of the HF
transformer and about 10 kV on the secondary side.
The new HF generator replaces the old type as spare part for older machines. The
colour of the new type is grey, the old is black. The new has screw connections for
the connection cables and different hole pattern for the mounting.
When fitting the new generator to older machines: three new mounting holes for the
generator must be drilled and the cable shoes must be removed from the connection
cables. Fit the generator with the connection terminal turned towards the base plate.
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8
Gas valve
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Operating the torch trigger switch causes semiconductor relay RE2 to conduct and
energise solenoid valve YV01. C82 and R111 form an HF filter.
9
Machine type indicator
As this circuit board is used in other machines, it is necessary for the processor to
know what type of machine it is controlling. A link is therefore provided connector
G to short out pull--up resistor R112. When it connects G1 -- G2 it indicates that the
machine is an LTN 255.
10
Thermal overload cutout
The thermal overload switch, ST01, is normally closed, which means that input K2
is at 10V. This voltage is dropped by the potential divider formed by resistors R31
and R32 to 4.8V, and used as an input voltage to the processor.
LED V05 indicates excessive temperature. When the thermal overload cutout
operates, the LED lights up.
If you connect a water cooler with water flow switch to the machine, remove
connector XP01 and connect the flow switch to XS25.
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11
Welding process control
The processor inputs are the set values of welding data and the arc voltage. The
processor also calculates a set value signal for welding current and supplies this to
the current control amplifier.
The process regulator control principle
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Hot start MMA
In the MMA normal welding mode, the welding current is briefly elevated at the
start of welding. The higher current setting is engaged for 150 milliseconds.
The starting current is twice the normal welding current (i.e. twice the set value),
subject to a maximum of 300A.
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Welding start, normal welding, MMA
1. Contact between the electrode and the workpiece.
2. Starting current for 150 ms.
In the MMA drop welding mode, the starting current is three times the set value, but
the duration is shorter at only 50 ms. The maximum starting currents are the same as
for normal welding.
Welding start, drop welding, MMA
1. Contact between the electrode and workpiece.
2. Starting current for 50 ms.
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12
Control panel interface circuits
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All machine functions are controlled from the panel on the front of the machine.
The display window and the LEDs are driven by IC21 and connected by a ribbon
cable to board contact B, pins 3--18.
The pulse generator on the front panel is supplied at +5V via inputs B25 and B26.
Pulses are supplied from the pulse generator to connections B23 and B24 with a 90_
mutual phase displacement. The pulse generator does only supply pulses when it’s
shaft is turned. Resistors R97 and R98 are pull--up resistors. IC11 squares up the
pulse flanks.
The two red
and the two green
pushbuttons are connected to 0V.
Pressing any of them pulls down the corresponding input (B19 - B22) to 0V, and the
signal is filtered by an RC filter network formed by capacitors C72 - C75 and
resistors R93 -- R96 before being applied to the processor.
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-- 17 --
13
Pulse width modulator
The pulse width modulator determines the frequency and pulse time of the MOSFET
transistors’ control pulses.
It is important that the frequency and maximum pulse time are within the specified
tolerances, see instructions on next page.
IC5 controls the pulse frequency, the pulse time and inhibition of pulses.
Transistor Q12 supplies the pulse transformer’s primary winding. Diodes D17 and
D18 are squelch diodes that protect Q12 against back--emf from the transformer.
Pulse width modulator and gate circuit
14
Gate circuit
The MOSFET transistors’ drive stage produces control pulses for the gate--source on
the power transistors. There is a separate output for each switch unit.
All gate circuits are galvanically isolated from other circuits on the board. The
insulation voltage between the pulse width modulator and the gate circuits is 4 kV.
WARNING! The gate circuits are at mains voltage.
The two gate circuits are identical, and so only one is described here.
When Q12 conducts, a voltage pulse is produced on the transformer’s secondary
winding. This pulse is conducted via D13, D14 and output E1 to the gate on the
MOSFET transistors. The pulse returns via the source, connection E2, D16 and
C36. The mean peak gate -- source voltage is 12--15V.
The gate pulse between E1 and E2 charges C36 to 5.6V. When Q12 turns off, the
voltage from the secondary of the pulse transformer changes polarity, causing Q14
and Q13 to start to conduct. The gate voltage becomes negative, turning off the
MOSFET transistors.
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-- 18 --
Checking the gate pulses
If circuit board AP02 or AP03 has failed, the gate pulses must always be checked.
Remove connections XS06 and XS07 (gate pulses). Connect a dummy gate load to
outputs E1 and E2 and to F1 and F2.
Dummy gate load
A set of different gate loads can be ordered from ESAB.
The part number is 0468 469 003. The gate loads can be used to the following
machines: LUC, LHL 130/160, LHL 250/315, LTL 160, LTL315, LUB 315,
LHN, LTN, LTR, LTO, MechTig 315 and Protig 315.
IMPORTANT: never check the gate pulses when AP02 and AP03 are
connected: use a dummy gate load.
The gate pulse minimum level must be - 3.5 to - 5.5V, and the average maximum
level 12 to 15V. Frequency must be 48.5 kHz ±0.5 kHz. Check that the maximum
pulse time, measured at a voltage level of +5V, is 43 ±1% of the cycle time.
IMPORTANT: The frequency and pulse time are very important parameters.
If they are incorrect, they can result in transistor failure in the main circuit.
If the gate pulse does not lie within these tolerances, replace circuit board AP01.
After replacing AP01, check the gate pulses again and soft--start the machine, as
described on page 27.
Gate pulses as measured across a dummy gate load on circuit board AP01
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-- 19 --
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-- 20 --
Component positions, circuit board AP01
1
1
1
WARNING:
High voltage within
the shaded area.
1
1
1
Terminals X1 to X6 are tied to
0V on the circuit board, and
must have good electrical contact with the screen enclosure.
1
26
1
1
1
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-- 21 --
TRANSISTOR BOARD AP02
Circuit diagram circuit board AP02 (transistor board positive)
Individual transistors must not be replaced: if the circuit board is faulty, it must be replaced
in its entirety. In addition, circuit board AP03 must also be replaced.
Instructions on removing and fitting the circuit board are to be found on page 37.
A01, A02
Connections A01 -- A02 are for the gate pulses from circuit board AP01.
D1 -- D3
Transient voltage protection.
D5
Back--emf protection diode (squelch diode) for main transformer TC02
when the transistors turn off.
D6
See R21.
F1
Fuse, for protection of circuit board AP01 if circuit board AP02 fails.
R21
R21, C3, C4 and D6 are limiting the peak voltage at transistors Q1 -- Q8.
Q1 -- Q8
MOSFET transistors. These require a special instrument
(see MOS TESTER on page 26) for testing.
Due to a change to transistors with higher current rating, transistor Q6
might not be fitted to the board. Spare part boards may have 7 or 8
transistors.
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-- 22 --
Component positions, circuit board AP02
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-- 23 --
TRANSISTOR BOARD AP03
Circuit diagram circuit board AP03 (transistor board negative)
Individual transistors must not be replaced: if the circuit board is faulty, it must be replaced
in its entirety. In addition, circuit board AP02 must also be replaced.
See on page 37 for instructions on removing and fitting the circuit board.
A01, A02
Connections A01 -- A02 are for the gate pulses from circuit board AP01.
B01, B02
When the machine is loaded, pulses from a trigger pulse winding on main
transformer TC02 are supplied to connections B01 and B02, for use as
gate pulses in controlling thyristor TY1.
D1 -- D3
Transient voltage protection.
D5
Back--emf protection diode (squelch diode) for main transformer TC02
when the transistors turn off.
D12
See R29.
Q1 -- Q8
MOSFET transistors. These require a special instrument
(see MOS TESTER on page 26 for testing.
Due to a change to transistors with higher current rating, transistor Q8
might not be fitted to the board. Spare part boards may have 7 or 8
transistors.
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-- 24 --
R21
Charging resistor, 12Ω, 10W, for buffer capacitors C02 and C03. When
energising the power unit, pulses from control circuit board AP01 are
delayed by 300 ms to allow the buffer capacitor to charge.
R26
Discharge resistor for buffer capacitor C03. Discharge time for the
capacitor, after turning off the mains power supply, is about two minutes.
R27
Discharge resistor for buffer capacitor C02. After turning off mains
power supply, discharge time for the capacitor is about two minutes.
R29
R29, C7, C8 and D12 are limiting the peak voltage at transistors Q1 - Q8.
TY1
Thyristor for shunting charging resistor R21 when the machine is loaded.
If TY1 did not conduct, resistor R21 would burn out when the unit is on
load.
Component positions, circuit board AP02
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-- 25 --
MOS TESTER
The MOS tester is a special instrument, and can be ordered only from ESAB.
Order number: 0468 469 001
Connect the instrument as follows:
S
Disconnect the power unit from the mains.
S
Disconnect capacitor C02 and C03.
S
Remove the gate connections from AP01.
S
Connect the clip on the red wire of the instrument to the red wire (the gate wire) on the
transistor board.
S
Connect the clip on the yellow wire of the instrument to the yellow wire (the source) on
the transistor board.
S
Connect the black wire to the cooling fins (drain).
Testing:
S
Press the pushbutton marked TEST.
S
If the board is healthy, both the red and green LEDs should flash alternately, about once a
second.
S
If the transistor board is short--circuited, the red LED will light continuously. (Note that
the green LED may also flash, or be continuously lit.)
S
If the transistor board is open--circuited, the green LED will be continuously lit. Check
that there is good electrical contact between the clip of the black wire and the cooling
fins.
IMPORTANT
Even if only one transistor board is indicated as faulty, both boards must be replaced.
Check the gate pulses from AP01 before commissioning the new transistor boards.
See instruction on page 19.
After replacement of the boards, the machine must be soft--started.
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-- 26 --
SOFT STARTING
S
Remove and insulate wires 07 and 08 from rectifier bridge V01, also remove and insulate
wire 09 to rectifier bridge V02: see the circuit diagram on page 8.
S
Connect an external power supply, having a current limit of 1A, to the positive and
negative connections on V01.
S
Adjust the power supply voltage to 30V.
S
Power the remaining parts of the unit from the normal power supply.
S
Measure the output voltage from the machine. This must be 5.5V ±1V.
S
Measure the secondary voltage from transformer TC02. With a voltage of 30V across
the buffer capacitor, the waveform must appear as shown below.
Secondary voltage at TC02 for 30V across the buffer capacitors
S
Measure the voltage with the oscilloscope probe
connected to A and the screen to B according to
the picture below.
Measuring points for the secondary voltage at TC02
Up to and including ser. no. 011--147--xxxx
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From serial no. 011--148--xxxx
-- 27 --
CONTROL PANEL AP05
AP06
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Circuit diagram control panel AP05
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-- 28 --
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Component positions control panel AP05
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-- 29 --
DISPLAY BOARD AP06
AP05
AP07
Circuit diagram display board AP06
The pulse generator Sw0 is transmitting pulses only when it’s shaft is turned.
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-- 30 --
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Component positions display board AP06
AP07 SUPPRESSION BOARD
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Circuit diagram and component positions, suppression board AP07
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-- 31 --
SUPPRESSION BOARD AP08
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cltn0e34
Diagram and component positions for the old version (0486 356 880) of circuit board AP08
Most of the machines produced before October 1998 are deliverd with circuit board 0486 356
880. As spare part for those machines we recommend circuit board 0486 577 880. The new
circuit board suppresses noise better than the old board. To fit the new board in older
machines a new mounting hole must be drilled in the mounting plate.
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-- 32 --
Diagram and component positions for the new version (0486 577 880) of circuit board AP08
SUPPRESSION BOARD AP09
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cltn0e27
Diagram and component positions for circuit board AP09
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-- 33 --
FAULT CODES
If the integral fault monitoring system detects a fault, the display shows Exx, where xx is a
two--digit number identifying the fault.
Faults E01 - E06 can be detected during the automatic self--test routine that is run when the
unit is switched on. Other faults can be detected as and when they occur.
E01
Memory error in internal RAM (in the processor).
If this code occurs, turn the machine off and then on again. If it persists, replace
circuit board AP01.
E02
Memory error in external RAM (outside the processor).
If this code occurs, turn the machine off and then on again.
If it persists, replace circuit board AP01.
E03
Memory error, program memory (EPROM).
If this code occurs, turn the machine off and then on again. If it persists,
replace circuit board AP01.
E04
Memory error, RAM memory contents test.
Check that the battery voltage is at least 2.5V. If it less than this, replace the battery.
If the voltage is correct, turn the machine off and then on again: if the fault persists,
replace circuit board AP01.
E05
Memory error, variable values outside limits in battery--backed RAM.
Perform the same checks as for error code E04.
E06
Battery voltage below 2.5V. Measure the battery voltage: if it is less than 2.5V,
replace the battery. If the battery voltage is over 2.5V, replace circuit board AP01.
This error code can be reset by pressing one of the arrow pushbuttons. This will
have no effect other than to clear the error code. The display will return next time
the machine is turned on, and can again be cleared by pressing one of the arrow
pushbuttons.
If the battery is not replaced before its voltage has fallen below 2.0V, error code E04
or E05 will be displayed. These error codes cannot be cleared.
E10
Incorrect power supply voltage (should be 20V), tolerance ¦1V.
Use a voltmeter to verify this fault. Measure the voltage from transformer TC01.
If the transformer output voltage is correct, but the 20V supply voltage is wrong,
replace circuit board AP01.
E11
Incorrect power supply voltage (should be - 15V), tolerance +2/--1V.
Use a voltmeter to verify this fault. Measure the voltage from transformer TC01.
If the transformer output voltage is correct, but the - 15V supply voltage is wrong,
replace circuit board AP01.
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-- 34 --
E13
High temperature. The thermal cutout has operated and indicating lamp V05 lights.
The machine has been overloaded. Check that the cooling fan is running, and that
the air filter is not blocked.
E14
Current servo fault: excessive difference between the actual value and the set value
of welding current. The power electronics circuitry is not capable of maintaining
the welding current that the process regulator is demanding.
Tolerances: ¦5A in TIG mode and ¦10A in MMA mode.
This code may occur when welding with electrodes which needs a higher voltage
than the machine can produce. It can also occur if the arc length is too long.
cltn0p10
The process regulator control principle
The process regulator servo compares the actual value signal and the set value
signal, as shown above. The set value signal is the current control signal from the
process regulator. The actual value signal is provided by the shunt signal, supplied
to the processor analogue inputs. These two signals are put through low--pass filters,
each with the same time constant, and are then compared with each other.
The time constant is about two seconds.
This fault code is reset when the welding current returns to within the tolerance
values, when welding is restarted or when the machine is turned off.
It is also possible to reset the display by pressing any of the pushbuttons. Doing this
has no effect other than to reset the display.
This fault code can sometimes occur during abnormal welding conditions, e.g. as a
result of a failed start.
When starting and finishing welding, the current is briefly outside the tolerance
limits. However, the above--mentioned filtering prevents these brief excursions
from triggering the fault code display.
Too low a power supply voltage to the + 5V voltage regulator. The display briefly
shows this symbol when the machine is turned off. If the voltage drops below the
permissible value when the machine is in use, the display will show this symbol
briefly and the machine will then stop.
See also POWER SUPPLY MONITORING on page 11.
The display shows this symbol if the machine’s program has crashed. This can be
caused, for example, by extreme external interference.
If this error code occurs, find and rectify the source of the interference, turn off the
machine, wait five seconds, and start it again.
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-- 35 --
DISASSEMBLY / REASSEMBLY
Fitting the diode modules
1.
Clean the contact surface of the heat sink with extremely fine abrasive paper.
2.
Apply a thin film of contact oil (see item 453 and 553 in the spare parts list) to the
contact surfaces.
3.
Fit the diode modules and tighten the screws A (M6) to a torque of 6 Nm. Tighten the
screws B (M4) to a torque of 1 Nm.
The screws C (1/4” 20UNC2B) are to be tightened to a torque of 6 Nm.
Before serial number 011--xxx--xxxx
From serial number 011--xxx--xxxx
From serial number 011--148--xxxx
From serial number 011--148--xxxx a new diode module is used. The rated current for the new
module, SCOMES MKK300.4, is 300 A. The rated current for the old module, Motorola
MURP20040CT, is 200 A. Because of the higher rating only two modules are needed for the
rectifier unit. The ordering no. for the new module is the same as for the old.
When replacing the diode modules in machines with serial number prior to 011--148--xxxx it
is sufficient to use only two modules if the new type, SCOMES MKK300.4, is fitted.
The busbars with item numbers 433, 434, 436, 533 and 536, see the spare parts list, are not
more available. If they have to be replaced, fit the new type of diode modules and the busbars
with item no. 643.
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-- 36 --
Removal of transistor circuit boards AP02 and AP03
1.
Remove all wires and busbars connected to the board.
2.
Remove the springs that hold the board (2) in position by prising them off with a
screwdriver (1) between the cooling flange and the spring.
Removal/refitting of transistor circuit board
Refitting the transistor circuit board
1.
When replacing the transistor circuit board, both boards must always be replaced and
new springs must be fitted.
2.
Clean the contact surface (3) of the heat sink with extremely fine abrasive paper.
3.
Apply a thin film of contact oil (see item 453 and 553 in the spare parts list) to the
contact surfaces.
4.
Place the circuit board (2) on the cooling fins. Secure first one spring on each side of the
board by pressing the spring down with a screwdriver (4). Then secure the remaining
springs.
NOTE: The springs must be fitted where there are components that are to be in contact
with the heath sink. Due to a change to transistors with higher current rating, there might
be less transistors on the spare part board than on the original board.
5.
When fitting cable lugs and busbars to the boards, it is important that the washers are
fitted in the correct order. Start by placing the lug on the foil, and then fit a flat washer, a
spring washer and finally the screw.
Connections to circuit board AP03
a Wire 045 to the connection between C02
and C03
b Busbar connected to positive on C03
c Busbar connected to negative on C02
d Wire 013 from negative of rectifier V02
e Gate connection from circuit board AP01
f Connector XS17 from transformer TC02
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-- 37 --
Fitting the main transformer TC02
When replacing the main transformer, it is also necessary to replace the transformer core.
This is because the core is bonded with adhesive, and cannot be disassembled.
Adhesive and tape are required when fitting a new transformer, in addition to the coil and
core. Part numbers for the requisite adhesive and tape are shown as Item 428 in the spare
parts list.
1.
Transfer wire 020 and connector XS17 to the new transformer. If the wire needs to be
replaced, it is important to use the correct type of insulation (Teflon)
clhn1p08
Fitting wire 020
2.
Apply a layer of tape (t) to each of the three airgaps in the transformer core. Use the tape
specified in the spare parts list.
3.
Apply Loctite 649 to the contact faces between the cores and between the core and coil.
Secure the transformer in position in the machine. The adhesive takes about 20 minutes
to harden.
cmha2p33
Airgap (t) in the transformer core
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-- 38 --
TECHNICAL DATA
Permitted load at:
35% duty cycle, TIG
35% duty cycle, MMA
60% duty cycle
100% duty cycle
250 A / 20 V
250 A / 30 V
180 A / 27 V
140 A / 26 V
Setting range, TIG
3 -- 250 A
Setting range, MMA
4 -- 250 A
Slope up
0 -- 10 sec
Slope down
0 -- 10 sec
Gas pre--flow
0 -- 25 sec
Gas post--flow
0 -- 25 sec
Pulse time
0.02 -- 5.0 sec
(0.001 -- 5.0 sec)
Pause time
0.02 -- 5.0 sec
(0.001 -- 5.0 sec)
Open--circuit voltage
70 -- 80 V
Open circuit power
40 W
Active power at max current MMA
8.78 kW
Apparent power at max current MMA
13.3 kVA
Power factor at max current MMA
0.65
Efficiency at max current MMA
0.85
Mains connection
Mains fuse, slow--blow
Mains cable, cross section
400 V 50--60 Hz
16 A
4 x 1.5mm2
Weight
25 kg
Dimensions l x w x h
515 x 285 x 415
Application class
Class of enclosure
IP23
The welding power source comply with the requirements set out in IEC 974--1
Duty cycle
The duty cycle refers to the time in per cent of a ten--minute period that you can weld at a
certain load without overloading the welding power source.
Enclosure class
The IP code indicates the enclosure class, i. e. the degree of protection against penetration by
solid objects or water. Equipment marked IP 23 is designed for indoor and outdoor use.
Application class
The symbol
indicates that the power source is designed for use in areas where there is an
increased electrical hazard.
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-- 39 --
LOAD CHARACTERISTICS
MAINTENANCE
LTN 255 normally need only a minimum of
maintenance. It is usually sufficient to blow it
clean with compressed air once a year and to
clean the fan air filter regularly.
If the machine is used in a dusty or dirty
environment, it should be blown clean more often.
Removing the filter
bt07d109
The machine’s memory is battery--backed. If the display shows the E06 error code, battery
voltage is low. See Error Codes on page 34.
NOTE that all guarantee obligations will be void if the customer carries out any work on the
machine during the guarantee period to rectify any faults.
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-- 40 --
INSTRUCTIONS
This chapter is an extract from the instruction manual for the LTN 255.
INTRODUCTION
Note:
This product is solely intended for arc welding.
LTN 255 is equipped with ARC PLUS, a new type of control that with MMA welding
provides a more intensive, more concentrated and smoother arc. It reacts quicker after a short
circuiting drop transfer, which reduces the risk of the electrode sticking.
In addition, the machine is equipped with Arc Force, which means that the power source’s
dynamics can be adjusted, softer or harder depending on the type of electrode and the
welder’s preference.
ARC PLUS -- because of the regulator’s good characteristics it is only necessary to change
the Arc Force settings in exceptional circumstances.
When drop welding using stainless steel electrodes a special feature on the machine can be
activated to facilitate welding.
LTN 255 is available in two designs, one with a central connector and one with an OKC
connector for a TIG torch. LTN 255 is supplied complete with a 5 metre mains cable, 5
metre return cable, gas hose and hose clips. Machines with a central connector are also fitted
with a safety bar to protect the connectors from impact.
As an accessory there is a loop handle to fit on the machines which acts as a cable reel as well
protecting the control panel. There are also two carriages available for transportation with a
gas cylinder and cooling unit.
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-- 41 --
INSTALLATION
WARNING
This product is intended for industrial use. In a domestic environment it may cause
radio interference. It is the user’s responsibility to take adequate precautions.
Mains voltage
400 V ¦10 %, 3--phase
Mains frequency
50 -- 60 Hz
Fuse, slow rupture
16 A
Mains cable, cross section
4x1.5 mm2
Welding cable, cross section
35 mm2
LTN 255 is equipped with mains voltage compensation, which means that a ¦10% variation
in the mains voltage only results in a ¦0.2% variation in the welding current.
To reduce the voltage drop when using a long cable it can be advisable to select a heavier
cable cross section.
1.
Place the equipment in a suitable place and make sure the rectifier is not covered or
set--up so that cooling is prevented.
2.
Make sure the machine is connected to the correct mains voltage.
Earth according to applicable directives.
3.
Connect the shielding gas.
4.
Connect the TIG torch and the return cable or the MMA welding cables.
The machine is now ready for welding.
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-- 42 --
OPERATION
4
5
3 2
8
1
9
10
11 12
7
6
1. Mains power switch
9. Gas nipple (connection of gas cylinder)
2. Yellow LED, indicating overtemperature
10. Connection for TIG torch
3. White indicating lamp
12. Connection for return cable when TIG
welding
ldi
4. Display
5. Setting knob
6. Push--buttons
7. Remote control connection
The welding cable and return cable should
b connectedd to 11 andd 12 when
be
h welding
ldi with
ih
coated electrodes
8. Dust filter
When the main power switch is switched on the white indicating lamp, on the front, is lit.
To take your mind off the risk of overloading the machine it has been equipped with an
integrated thermostat that trips if the temperature becomes too high.
When this occurs the welding current is cut out and the yellow indicating lamp comes on. In
addition, the error code ”E13” is displayed. When the temperature has dropped the thermostat
automatically resets.
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-- 43 --
Control panel
On the front of the machine there is a control panel for the selection of functions and setting
of parameters. This consists of a display, setting knob, LEDs and push--buttons.
By using the push--buttons you can move between the different functions. The selected
function is indicated by respective LEDs coming on.
One line at a time is set. The current line is indicated by a red LED. Movement between lines
takes place using the red arrow keys.
Movement within each line takes place using the green arrow keys.
All settings are made using the setting knob. The LEDs to the right of the display indicate the
actual unit (ampere/volt/seconds). On the lines where only a function is selected, ”------” is
shown on the display.
Description of the functions:
S
S
S
S
Line 1
Line 2
Line 3
Line 4
S
Line 5
S
S
Line 6
Line 7
bt07d002
Line 1
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TIG welding or MMA welding
If MMA welding is chosen, the current is set here and lines 2--5 are ignored.
-- 44 --
Line 2
TIG/HF ignition or TIG/Liftarc ignition
If HF ignition has been selected, the HF generator will be activated when the torch
trigger switch is operated. The HF generator is activated for 0.75 seconds: if the arc
has not struck during this time, the machine turns off the HF generator.
Operate the LIFTARC ignition feature as shown below.
bt07t00
Place the electrode against the workpiece .
Press the torch switch
Tilt the torch a little, lift and an arc is produced
To stop -- release the torch trigger
bt07t002
Line 3
Continuous current or pulsed current O O -- O
Line 4
2 stroke or 4 stroke trigger action
2 stroke trigger action means that the arc is ignited when the torch trigger is
pressed in and is extinguished when the trigger is released.
4 stroke trigger action means that when the torch trigger is pressed in ”1” the
machine starts with the pilot current and then slopes up to the set current
when the trigger is released ”2”. When the trigger is pressed in again ”3” the
machine slopes down to the pilot current. The arc is extinguished when the
trigger is released ”4”.
bt07d003
cltn1de4
-- 45 --
Line 5
Parameter setting
1. Gas pre flow
2. Slope up
3. Pulse current or continuous current
4. Pulse time
5. Pause current
6. Pause time
7. Slope down
8. Gas post flow
0--25 s
0--10 s
3--250 A
0.02--5.0 s (0.001--5.0 s)
3--250 A
0.02--5.0 s (0.001--5.0 s)
0--10 s
0--25 s
Line 6
Measurement instrument
Shows the welding current or arc voltage during the present welding run.
The measurement instrument has a hold function that locks the measurement
value when the welding run is stopped.
Line 7
Welding data memory O O 1 O 2 O1--2 O
A
Four different sets of welding data settings can be stored in the machine’s
memory, two for TIG mode and two for MMA mode.
The following can be stored:
TIG: selected option from line 3 (continuous or pulsed current) All settings
on line 5.
MMA: Welding current
The welding data memory is changed using the green arrow
keys.
Changes can also be made by quickly pressing the torch trigger, regardless of
whether you are welding or not.
To activate the possibility of jumping between programs both the green
arrow
keys should be pressed simultaneously.
When the jump function is activated an indicating lamp comes on. O 1--2
If the 4 stroke trigger action is selected, quickly pressing the trigger will
switch the welding data. The same thing applies in 2 stroke trigger action if
you are not welding. During welding, using 2 stroke trigger action, you
release the trigger momentarily to change the welding data.
Aristotig has battery backup so that the settings remain in memory even
when the machine is switched of or disconnected from the power supply.
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-- 46 --
Other functions
Drop welding (MMA)
Drop welding can be used when welding with stainless steel electrodes.
The technique involves the arc switching between igniting and extinguishing to allow better
control over the heat transfer. The electrode only needs to be lifted a little for the arc to be
extinguished.
The machine should be in the current setting mode when the function is activated. Press both
of the green arrow
keys simultaneously for 2 seconds and the symbol ”--_--” indicates
that the function is activated.
This mode remains active even if the machine is switched off. The machine is reset for
normal welding again using the same method and ”-- - - ” is then indicated on the display.
Arc Force (MMA)
The Arc Force setting changes the machine’s dynamic. A softer or harder arc can be obtained.
The machine should be in the current setting mode when activating the function by pressing
simultaneously for 2 seconds. The display shows a value
the two red arrow keys
between 0 and 100. The higher the value the harder the arc.
Press one of the buttons and the power source returns to the normal operating mode. The set
Arc Force value remains. Different Arc Force settings can be stored in the machine’s two sets
of welding data memory.
Pulse time/Pause time (TIG)
Normally the setting range for these parameters is 0.02--5.0 s. Through pressing the two green
arrows simultaneously for 2 seconds, times down to 0.001 s can be set. This extended setting
range remains until the machine is reset using the same method. When activating the function
the machine should be in the mode for setting the pulse time/pause time. Note that times
below 0.250 s are displayed without the decimal point.
Remote control
Using the remote control socket on the machine the current can be remotely regulated in TIG
and MMA modes.
If pulsed current is selected in TIG mode, it is the pulsed current that is remotely regulated.
The set value from the remote control is shown on the display by stepping to the position
where the current should be set when not using the remote control.
Switching to the remote mode takes place automatically when the unit is connected.
This is confirmed by the LED coming on. O
A
(NOTE! the pins L and M in the remote control’s connecting plug must be strapped for
automatic connection to take place).
The following remote controls can be connected:
PHA1, PHA2, PHA5, PHB1, PHB2, PHC2 and FS002.
NOTE: When using FS002 the slope--up and slope--down times should be set to 0 seconds.
SPARE PARTS
The spare parts list for the LTN 255 is published in a separate document with filename /
ordering no. 0457 328 990
cltn1de4
-- 47 --
NOTES
notes
-- 48 --
notes
-- 49 --
ESAB subsidiaries and representative offices
Europe
AUSTRIA
ESAB Ges.m.b.H
Vienna--Liesing
Tel: +43 1 888 25 11
Fax: +43 1 888 25 11 85
BELGIUM
S.A. ESAB N.V.
Brussels
Tel: +32 2 745 11 00
Fax: +32 2 726 80 05
THE CZECH REPUBLIC
ESAB VAMBERK s.r.o.
Prague
Tel: +420 2 819 40 885
Fax: +420 2 819 40 120
DENMARK
Aktieselskabet ESAB
Copenhagen--Valby
Tel: +45 36 30 01 11
Fax: +45 36 30 40 03
FINLAND
ESAB Oy
Helsinki
Tel: +358 9 547 761
Fax: +358 9 547 77 71
FRANCE
ESAB France S.A.
Cergy Pontoise
Tel: +33 1 30 75 55 00
Fax: +33 1 30 75 55 24
GERMANY
ESAB GmbH
Solingen
Tel: +49 212 298 0
Fax: +49 212 298 204
GREAT BRITAIN
ESAB Group (UK) Ltd
Waltham Cross
Tel: +44 1992 76 85 15
Fax: +44 1992 71 58 03
ESAB Automation Ltd
Andover
Tel: +44 1264 33 22 33
Fax: +44 1264 33 20 74
HUNGARY
ESAB Kft
Budapest
Tel: +36 1 20 44 182
Fax: +36 1 20 44 186
ITALY
ESAB Saldatura S.p.A.
Mesero (Mi)
Tel: +39 02 97 96 81
Fax: +39 02 97 28 91 81
THE NETHERLANDS
ESAB Nederland B.V.
Utrecht
Tel: +31 30 248 59 22
Fax: +31 30 248 52 60
NORWAY
AS ESAB
Larvik
Tel: +47 33 12 10 00
Fax: +47 33 11 52 03
POLAND
ESAB Sp.z.o.o
Warszaw
Tel: +48 22 813 99 63
Fax: +48 22 813 98 81
PORTUGAL
ESAB Lda
Lisbon
Tel: +351 1 837 1527
Fax: +351 1 859 1277
SLOVAKIA
ESAB Slovakia s.r.o.
Bratislava
Tel: +421 7 44 88 24 26
Fax: +421 7 44 88 87 41
SPAIN
ESAB Ibérica S.A.
Alcobendas (Madrid)
Tel: +34 91 623 11 00
Fax: +34 91 661 51 83
SWEDEN
ESAB Sverige AB
Gothenburg
Tel: +46 31 50 95 00
Fax: +46 31 50 92 22
ESAB International AB
Gothenburg
Tel: +46 31 50 90 00
Fax: +46 31 50 93 60
SWITZERLAND
ESAB AG
Dietikon
Tel: +41 1 741 25 25
Fax: +41 1 740 30 55
North and South America
Asia/Pacific
CHINA
Shanghai ESAB A/P
Shanghai
Tel: +86 21 6539 7124
Fax: +86 21 6543 6622
INDIA
ESAB India Ltd
Calcutta
Tel: +91 33 478 45 17
Fax: +91 33 468 18 80
INDONESIA
P.T. Esabindo Pratama
Jakarta
Tel: +62 21 460 01 88
Fax: +62 21 461 29 29
MALAYSIA
ESAB (Malaysia) Snd Bhd
Selangor
Tel: +60 3 703 36 15
Fax: +60 3 703 35 52
SINGAPORE
ESAB Singapore Pte Ltd
Singapore
Tel: +65 861 43 22
Fax: +65 861 31 95
ESAB Asia/Pacific Pte Ltd
Singapore
Tel: +65 861 74 42
Fax: +65 863 08 39
Representative offices
BULGARIA
ESAB Representative Office
Sofia
Tel/Fax: +359 2 974 42 88
EGYPT
ESAB Egypt
Dokki--Cairo
Tel: +20 2 390 96 69
Fax: +20 2 393 32 13
ROMANIA
ESAB Representative Office
Bucharest
Tel/Fax: +40 1 322 36 74
RUSSIA-- CIS
ESAB Representative Office
Moscow
Tel: +7 095 937 98 20
Fax: +7 095 937 95 80
ESAB Representative Office
St Petersburg
Tel: +7 812 325 43 62
Fax: +7 812 325 66 85
Distributors
For addresses and phone
numbers to our distributors in
other countries, please visit our
home page
www.esab.com
SOUTH KOREA
ESAB SeAH Corporation
Kyung--Nam
Tel: +82 551 289 81 11
Fax: +82 551 289 88 63
UNITED ARAB EMIRATES
ESAB Middle East
Dubai
Tel: +971 4 338 88 29
Fax: +971 4 338 87 29
ARGENTINA
CONARCO
Buenos Aires
Tel: +54 11 4 753 4039
Fax: +54 11 4 753 6313
BRAZIL
ESAB S.A.
Contagem--MG
Tel: +55 31 3369 4333
Fax: +55 31 3369 4440
CANADA
ESAB Group Canada Inc.
Missisauga, Ontario
Tel: +1 905 670 02 20
Fax: +1 905 670 48 79
MEXICO
ESAB Mexico S.A.
Monterrey
Tel: +52 8 350 5959
Fax: +52 8 350 7554
USA
ESAB Welding & Cutting Products
Florence, SC
Tel: +1 843 669 44 11
Fax: +1 843 664 44 58
ESAB AB
SE-- 695 81 LAXÅ
SWEDEN
Phone +46 584 81 000
www.esab.com
031021
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