0740 801 016
020226
LTS 160/250
Prowelder 160/250
Service manual
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LIST OF CONTENTS Page
READ THIS FIRST 4................................................................
TECHNICAL DATA 5................................................................
LOAD CHARACTERISTICS 6........................................................
COMPONENT DESCRIPTION 7......................................................
CONNECTION DIAGRAM LTS 160 10..................................................
CONNECTION DIAGRAM LTS 250 12..................................................
DESCRIPTION OF OPERATION, CIRCUIT BOARD AP1 14..............................
AP1:1 Power supply 14..........................................................
AP1:2 Shunt input with amplifier AP10 16..........................................
AP1:3 Arc voltage input 17.......................................................
AP1:4 Gate circuit, AP4 18.......................................................
LTS 160: Checking the gate pulses from AP4 19..............................
LTS 160: Checking the gate pulses from AP1 to AP4 20.......................
LTS 250: Checking the gate pulses from AP4 21..............................
LTS 250: Checking the gate pulses from AP1 to AP4 22.......................
AP1:5 CAN bus 23..............................................................
AP1:6 Thermal overload switch 24.................................................
AP1:7 Input for a water flow monitor switch 25......................................
Component positions, circuit board AP1 27............................................
LTS 160: TRANSISTOR BOARD AP2 28...............................................
LTS 160: TRANSISTOR BOARD AP3 30...............................................
LTS 250: TRANSISTOR BOARD AP2 32...............................................
LTS 250: TRANSISTOR BOARD AP3 34...............................................
MOSTEST ER 36.....................................................................
LTS 160: SOFT STARTING 37........................................................
LTS 250: SOFT STARTING 38........................................................
LTS 160: SUPPRESSION BOARD AP5 39.............................................
LTS 250: SUPPRESSION BOARD AP5 39.............................................
DESCRIPTION OF OPERATION, CIRCUIT BOARD AP6 40..............................
AP6:1 Power supply / The CAN bus 40...........................................
AP6:2 Torch switch 40...........................................................
AP6:3 HF generator 41..........................................................
AP6:4 Gas valve 41.............................................................
AP6:5 Gas flow monitor 42.......................................................
AP6:6 Extra inputs and outputs 42.................................................
Component positions, circuit board AP6 43............................................
DESCRIPTION OF OPERATION, CIRCUIT BOARD AP8 44..............................
Component positions, circuit board AP8 45............................................
DESCRIPTION OF OPERATION, CIRCUIT BOARD AP9 46..............................
AP9:1 Power supply / CAN bus 47................................................
AP9:2 Motor drive, rotation 48....................................................
AP9:3 Tools 50.................................................................
AP9:4 Motor drive, wire feed 51...................................................
Component positions, circuit board AP9 53............................................
DESCRIPTION OF OPERATION, SETTING UNIT 54.....................................
B1 Power supply 54..........................................................
B2 The display window 54.....................................................
B3 Communication 56........................................................
B4 Sounder 56...............................................................
Component positions, circuit board AP1B 57...........................................
Circuit board AP3B 58..............................................................
Replacing the battery 59............................................................
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ERROR LOG 60.....................................................................
Error codes 60.....................................................................
Overview of Error Codes 62.........................................................
Specification of Error Codes 63......................................................
Incorrect--editing codes 67...........................................................
SERVICE FUNCTIONS 68............................................................
DISASSEMBLY / REASSEMBLY 82....................................................
Removal of transistor circuit boards AP2 and AP3 82...................................
Refitting the transistor circuit board 82................................................
Assembling the diode modules 83....................................................
Fitting the main transformer , TC2 84.................................................
INSTRUCTIONS 85..................................................................
SAFETY 85........................................................................
INTRODUCTION 86.................................................................
Equipment 86......................................................................
Programming box 86...............................................................
Applications 87....................................................................
INSTALLATION 87..................................................................
Lifting instructions 87...............................................................
Mains voltage connection 88.........................................................
Termination resistance 88...........................................................
Connection of complete welding system 89............................................
OPERATION 90.....................................................................
Controls and connections 90.........................................................
Cooling unit 91.....................................................................
Overheating protection 91...........................................................
Flow guard, water 91...............................................................
Flow guard, gas 91.................................................................
Error messages 91.................................................................
MAINTENANCE 91..................................................................
ACCESSORIES 92..................................................................
ORDERING OF SPARE PARTS 94....................................................
SPARE PARTS LIST 95..............................................................
NOTES 111..........................................................................
Rights reserved to alter specifications without notice.
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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 connection diagrams as a form of index for the descriptions of operation. The
circuit board is divided into numbered blocks, which are described individually in more
detail in the descriptions of operation. All component names in the connection diagram are
listed in the component description.
This manual contains details of all design changes that have been made up to and including
February 2002.
The LTS 160 and LTS 250 are 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
READ AND UNDERSTAND THE INSTRUCTION MANUAL BEFORE INSTALLING OR OPERATING.
ARC WELDING AND CUTTING CAN BE INJURIOUS TO YOURSELF AND OTHERS. TAKE PRECAU-
TIONS 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.
PROTECT YOURSELF AND OTHERS!
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TECHNICAL DATA
LTS 160 LTS 250
Mains voltage 230 V ±10%, 1 50/60 Hz 400 V ±10%, 3 50/60 Hz
Permissible load at
35 % duty cycle
60 % duty cycle
100 % duty cycle
160 A / 16 V
110A/15V
80 A / 13 V
250 A / 20 V
180 A / 17 V
140 A / 16 V
No--load power 50 W 55 W
Power factor 0.68 0.61
Efficiency ≥0.75 ≥0.75
No--load voltage 70 V 70 V
Primary current
at 100% duty cycle
9A 8A
Arc strike HF HF
Dimensions l x w x h
without cooling unit
with cooling unit
515 x 285 x 620 mm
515 x 285 x 835 mm
515 x 285 x 620 mm
515 x 285 x 835 mm
Weight without cooling unit
with cooling unit
37 kg
56.5 kg
38 kg
57.5 kg
Temperature class F (155 _C) F (155 _C)
Enclosure type IP 23 IP 23
Application class
Setting range
LTS 160 LTS 250
Operating range, current 5 A / 10 V -- 160 A / 16 V 5 A / 10 V -- 250 A / 20 V
Steps of adjustment, current 1A 1A
Wire feed speed 0.10 -- 2.50 m/min 0.10 -- 2.50 m/min
Pulse and background time 0.01 -- 25.0 seconds 0.01 -- 25.0 seconds
Pre--heat time 0 -- 600 seconds 0 -- 600 seconds
Gas pre-- and post--flow 0 -- 6000 seconds 0 -- 6000 seconds
Slope--up and slope down 0.1 -- 25 seconds 0.1 -- 25 seconds
Sector 0 -- 10 revolutions 0 -- 10 revolutions
Steps of adjustment, sector
break point
0.001 revolution 0.001 revolution
These welding power units fulfil the requirements of 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 with increased electrical
hazard.
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LOAD CHARACTERISTICS
LTS 160
LTS 250
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COMPONENT DESCRIPTION
WARNING !
STATIC ELECTRICITY can damage circuit
boards and electronic components.
S
SS
S Observe precautions for handling electrostatic
sensitive devices.
S
SS
S Use proper static--proof bags and boxes.
ESD
WARNING
Many parts of the power unit ar e at mains voltage.
AP1 Control circuit board; see the function description on page 14.
AP2 Circuit board with power transistors for the positive pole, see description
for the LTS 160 on page 28 and for the LTS 250 on page 32.
WARNING! the transistors are connected to mains voltage potential.
AP3 Circuit board with power transistors for the n egative pole, see description
for the LTS 160 on page 30 and for the LTS 250 on page 34.
WARNING! the transistors are connected to mains voltage potential.
AP4 Gate pulse driver board; see the description on page 18.
AP5 Circuit board, suppression (EMC). See circuit diagram on page 39.
AP6 Circuit board for TIG welding; see the function description on page 40.
AP8 Interface circuit board for PC; see the function description on page 44.
AP9 Motor circuit board for rotation and wire feed; see the function description
on page 46.
AP10 Circuit board with shunt amplifier; see the description on page 16.
AP11 HF generator; see the description on page NO TAG.
C1 Capacitor, transient protection.
C2, C3 Capacitor, 1000←F, buffer/smoothing capacitor.
Time to discharge after turning off the unit: about two minutes.
Capacitor C3 is only mounted in the LT S 250.
C4 Capacitor, transient protection.
C5 2 -- capacitors, 4.7←F, see L02.
C6, C7, C9 Capacitor, transient protection.
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C10 LTS 250: 2 -- capacitors, 1 nF. P rotection against transient voltages.
EV1 Fan, 24 VDC.
EV2 Fan, 24 VDC. Only monted in the LTS 250.
FU1 Fuse 2 A, slow blow.
FU2 Fuse 3.15 A, slow blow.
FU3 Fuse 2 A, slow blow.
FU4 Fuse 800 mA, slow blow.
FU8, FU9 Fuse 1.25A, slow blow.
HL1 Lamp, 28 V, white, lights when mains power is on.
L1 Secondary inductor.
L2 Inductor, forms an LC circuit with C5 and V6 to reduce the risk of arc
extinction at low welding currents.
When V3 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 V6 prevents capacitor C5 from going negative.
L3 LTS 160: Primary inductor, improves the machine’s form factor, i.e.
reduces the mains load.
LTS 250: Ferrite ring core, transient protection.
L4, L5 Ferrite ring core, t ransient pr otection.
QF1 Mains power supply switch.
R1 Resistor.
RS1 LTS 160: Shunt, 119 mV at 140 A.
LTS 250: Shunt, 119 mV at 250 A.
SL2 Gas flow switch; see the description on page 42.
ST1 Thermal overload cutout; see the description on page 24.
TC1 Control power transformer.
TC2 Main transformer. For fitting instructions, see page 84.
TV1 HF transformer; see t he description on page 41.
V1, V2 Mains rectifier bridge, 35 A, 1200 V. After replacing the rectifier bridges,
the machine must be soft--started: see instructions on page 37.
Rectifier bridge V2 is only mounted in the LTS 250.
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V3, V4 Rectifier and freewheel diodes.
V3 rectifies the welding current.
During the time interval between two voltage pulses from transformer TC2,
the freewheel diode V4 maintain the welding current from inductor L1.
On the cooling fins one respectively three diode modules are mounted.
Each diode module consists of two diodes.
For installation instructions, see page 83.
From serial number 008--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 in the
LTS 250. The ordering no. for the new module is the same as for the old.
V5 LED, yellow. Lights when thermal cutout ST1 operates (breaks) as a result
of high temperature.
V6 Diode, see L2.
X.. Terminal block.
XP . . Pin connector.
XS . . Sleeve connector.
XS12 Connector for voltage supply to cooling unit.
XS13, XS14 Welding current terminal, OKC type.
XS53 Panel jack, for connection of water--flow guard
YV1 -- YV3 Solenoid valves for gas.
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CONNECTION DIAGRAM LTS 160
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CONNECTION DIAGRAM LTS 250
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DESCRIPTION OF OPERATION, CIRCUIT BOARD AP1
Sections AP1:1 -- AP1:7 r efer to the connection diagrams for LTS 160 and LTS 250 and the
components position diagram for circuit board AP1.
If circuit board AP1 is replaced, the gate pulses must be checked and the machine must be
soft--started: see pages 18, 37 and NO TAG.
AP1:1 Power supply
Voltage regulator VR2 supplies fan EV1 and EV2 with 28V. F an EV2 is only
fitted in the LTS 250. FU4 is a 800 mA slow-- blow fuse.
FU3 is a 2 A slow--blow fuse. Indicating lamp HL1 is fitted on the front of the
machine.
+5V The +5V supply is regulated by voltage regulator VR5. IC16 forms a
reset circuit that monitors both the regulated 5V supply after the
regulator and the +15V.
If the voltage after the regulator drops below 4.65V, IC16 generates a
reset signal to the processor, the CAN controller and the PWM circuit.
The setting unit displays error code 5.
When the voltage rises through 4.65V on starting, IC16 maintains the
reset signal for 200 ms to ensure that the machine program starts
correctly.
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IC16 monitors the voltage to the regulator input in order to make a
controlled shutdown in the event of low mains voltage, loss of power
supply or turning off the machine.
If the voltage across C110 drops below 6V, the gate pulses to the IGBT
transistors are cut off immediately and the processor receives an ’early
warning’ signal that enables it to shut down the process in a controlled
manner.
+15V If the +15V supply is outside its tolerance of 14.0 -- 15.6V, the setting
unit displays error code 8.
--15V If this voltage varies outside its tolerance of 14.0 -- 16.1V, the setting
unit will display error code 9.
+20V Supplies the pulse transformer that drive the switch transistors.
The voltage must be between 19.4V and 21.7V. If it is not, the gate
pulses to the switch transistors are interrupted, and the setting unit
displays error code 10.
Power supply to the CAN bus
SeeCANBUSonpage23.
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AP1:2 Shunt input with amplifier AP10
Shunt amplifier circuit board AP10 is supplied with ¦15 V from circuit board
AP1. At no--load voltage, the circuit board’s neutral voltage (0 V) is at the same
potential as the welding circuit negative connection.
In the LTS 160 and LTS 250 the welding current can be set in 1 A steps. The
lowest current that can be set is 5A.
In the LTS 160, 119mV ¦1mV shunt voltage corresponds to 140 A welding
current. In the LTS 250, 119mV ¦1mV shunt voltage corresponds to 250 A
welding current. The signal from the shunt is amplified by the shunt amplifier,
so that a 119 mV input signal from the shunt produces a 6.66 V output signal.
If AP1, AP10 or the shunt RS1 are replaced, the machine must be recalibrated to
ensure that it delivers the correct current. Apply a resistive load to the machine
and adjust the current by means of potentiometer R21.
Adjust the LTS 160 to give 100 A±0.5A at 14 V.
Adjust the LTS 250 to give 100 A±0.5A at 14 V.
Use an accurately calibrated external shunt and multimeter when making
the adjustments.
Use the service functions on page NO TAG to set the current when adjusting the
machine.
Remember also to check the current at low values: 8A at 10.3 V, for which the
tolerance is 0.3A. If the current is outside this tolerance, adjust it by means of
offset potentiometer R201.
Component positions for shuntamplifier AP10
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AP1:3 Arc voltage input
The arc voltage input senses the output voltage from the power unit. The arc
voltage signal is used to display the arc voltage on the setting unit and to
generate measuring values to the Weldoc WMS 4000.
Checking the arc voltage input
The circuit board has been correctly adjusted when the machine is supplied.
These instructions allow the arc voltage input to be checked and, if necessary,
adjusted.
Use an accurately calibrated external instrument for the work.
Connect the voltmeter and dummy load as shown below: the dummy load
should be resistive, to produce a current of 100A at 14V.
Use the service functions on page NO TAG to set the current.
V = external voltmeter. R = load resistance.
The setting unit must display a value which is 0.1 -- 1.2V lower than the value of
the external voltmeter.
Use potentiometer R103 to adjust the reading on the setting unit.
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AP1:4 Gate circuit, AP4
Pulse width modulator and gate circuit
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 the instructions fo r checking t he gate pulses on the
following pages.
The PWM cir cuit on circuit board AP1 controls the pulse frequency, the pulse
time and inhibition of pulses. Transistor Q2 supplies the pulse transformer’s
primary winding. Diodes D27 -- D30 are squelch diodes that protect Q2 against
back--emf from the transformer.
NOTE
The frequency and pulse time is not the same for the LTS 160 and the LTS 250.
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.
The gate circuits are galvanically isolated from circuit board AP1.
The insulation voltage between the pulse width modulator and the gate circuits
is 4kV.
WARNING! The gate circuits are at mains voltage.
The two gate circuits are identical, and so only one is described here.
When Q2 conducts, a voltage pulse is produced on the transformer’s secondary
winding. This pulse is conducted via D8, D6 and output C1 to the gate on the
MOSFET transistors. The pulse returns via the source, connection C2, D9 and
C6--C9. The mean peak gate -- source voltage is about 14 V.
The gate pulse between C1 and C2 charges C6--C9 to 5.6 V. When Q2 turns off,
the voltage from the secondary of the pulse transformer changes polarity,
causing Q4, Q5 and Q6 to start to conduct. The gate voltage becomes negative,
turning off the MOSFET transistors.
Dummy gate load
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Component positions for circuit board AP4
LTS 160: Checking the g ate pulses from AP4
If circuit board AP2 or AP3 has failed, the gate pulses must
always be checked.
Remove connections XS10 and XS11 (gate pulses). Connect a
dummy gate load to outputs C1 and C2 and to D1 and D2.
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, LTL 315, LUB 315,
LHN, LTN, LTO, LTP, LTR, LTS, MechTig 315 and Protig 315.
IMPORTANT:
Never check the gate pulses when AP2 and AP3 are connected to AP4: use
a dummy gate load. AP2 and AP3 are at mains voltage.
The minimum gate pulse level must be --2 to -- 4 V and its maximum value must
be 13.5 to 16 V. The frequency must be 36.5 kHz ¦0.5 kHz. Check that the
maximum pulse time is 40.5 ¦1% of the cycle time, measured at a level of +5V.
If the gate pulse does not lie within these tolerances, check also the pulses from
circuit board AP1, see the instructions on page 20.
The frequency and pulse time are very important parameters. If they are
incorrect, they can result in transistor failure in the m ain circuit.
Gate pulses as measured across a gate load on circuit board AP4 in the LTS 160
If the pulse shape, pulse time and cycle time are correct, the check can be
concluded here.
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LTS 160: Checking the g ate pulses from AP1 to AP4
Pulse width modulator and gate circuit
Measure the pulses when they are loaded by a 1kΩ resistor.
Start the machine and use the service functions to set a current, see page
NO TAG. The pulse shapes should be as shown below.
LTS 160
Gate pulses from AP1 when the output is connected to a 1kΩ resistor
Connect the oscilloscope with its screen to connector G1 and the probe to G2.
Measure the following pulse par ameters:
S Frequency: 36.5 + 0.5 kHz.
S Pulse time: 38.5% ¦1% of the cycle time, as measured at 10V
S The maximum pulse voltage must be about 20V
S The minimum voltage must be about 0V
If the gate pulse does not lie within these tolerances, replace circuit board AP1.
If the gate pulse lie within the tolerances, but not the pulses from AP4, replace
circuit board AP4.
After replacing AP1 and/or AP4, check the gate pulses again and soft--start the
machine, as described on page 37.
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