ESAB OrigoArc 150 User manual

0740 800 162 Valid for serial no. 316--xxx--xxxx to 405--xxx--xxxx040830
OrigoArc 150
Service manual

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Rights reserved to alter specifications without notice.
READ THIS FIRST 3.................................................................
INTRODUCTION 3...................................................................
TECHNICAL DATA 4.................................................................
WIRING DIAGRAM 4.................................................................
Component description 5..........................................................
OrigoArc 150 6....................................................................
DESCRIPTION OF OPERATION 8.....................................................
2AP1 Power supply board 8.......................................................
2AP1:1 Interference suppressor circuit 8............................................
2AP1:2 Primary and secondary circuit 8............................................
2AP1 Component positions 9....................................................
15AP1 Power board 10.............................................................
Charging circuit 10..................................................................
Supply to 2AP1 11..................................................................
Gate driver stages 11................................................................
Switching circuit 11..................................................................
15AP1 Component positions 12....................................................
15AP2 Secondary board 13.........................................................
15AP2 Component positions 13....................................................
20AP1 Control board 14............................................................
20AP1:1 Power supply 14...........................................................
20AP1:2 Current reference input 14..................................................
20AP1:3 Pulse width modulator 14...................................................
20AP1:4 Temperature monitoring 15..................................................
20AP1:5 Shunt input 15............................................................
20AP1:6 Arc voltage monitoring 16...................................................
20AP1 Component positions 16....................................................
SERVICE INSTRUCTIONS 17..........................................................
What is ESD? 17...................................................................
Special tools 17....................................................................
Soft starting 18....................................................................
Checking rectifier and freewheel diodes 20..........................................
Checking the gate pulses 21........................................................
Checking the semiconductor module 22.............................................
Mounting components on the heat sink 23...........................................
INSTRUCTIONS 24...................................................................
SAFETY 24........................................................................
INSTALLATION 25..................................................................
OPERATION 26....................................................................
Connections and control devices 26.................................................
Welding 26
........................................................................
Overheating protection 26..........................................................
MAINTENANCE 26.................................................................
SPARE PARTS 26....................................................................
NOTES 27...........................................................................

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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 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 manual is valid for OrigoArc 150 with serial no. 316--xxx--xxxx, 328--xxx--xxxx,
341--xxx--xxxx, 405--xxx--xxxx.
The OrigoArc 150 is designed and tested in accordance with international and
European standards IEC/EN 60974--1 and EN 50199.
On completion of service or repair work, it is the responsibility of the person(s)
performing the work to ensure that the product still complies with the requirements of
the above standard.
INTRODUCTION
The OrigoArc 150 is a welding current power source intended for use with coated
electrodes (MMA welding).
The power module of the power source is a single forward converter, operating at a
switching frequency of 65 kHz. IGBT transistors are used as the switching elements. All
power semiconductors are built into modules.
Schematic diagram of the power source

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TECHNICAL DATA
Mains voltage 230 V ±10% 1µ50/60 Hz
Fuse (delayed--action) 16 A
Primary current Imax 36 A
Primary current Ieff 21 A
Voltage/current range (DC) 8 A / 20 V -- 150 A / 26 V
Maximum permissible load at
25% duty cycle
35% duty cycle
60% duty cycle
100% duty cycle
150 A / 26 V
140 A / 25.5V
110 A / 24.5V
90 A / 23.5V
Power factor at maximum current 0.62
Efficiency at maximum current 77%
Open--circuit voltage 58 -- 75 V
Operating temperature -- 1 0 ˚C-- +40˚C
Constant A--weighed sound pressure <70db
Dimensions, l x b x h 380 x 180 x 300 mm
Weight 8kg
Enclosure class IP23C
Application class
Duty cycle
The duty cycle refers to the time as a percentage of a ten--minute period that you can weld at a cer-
tain load without overloading.
Enclosure class
The IP code indicates the enclosure class, i. e. the degree of protection against penetration by solid
objects or water. Equipment marked IP23 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.
WIRING DIAGRAM
The power source consists of a number of function modules, which are described in the
component descriptions on the following pages. Wire numbers and component names in
the wiring diagrams show to which module each component belongs.
Wires/cables within modules are marked 100 -- 6999.
Circuit boards within each module have names such as 20AP1 -- 20AP99.
15 = module association, 1--69
AP = circuit board
1 = individual identification number, 0--99
Components within modules -- are named in a similar way.

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WARNING !
STATIC ELECTRICITY can damage circuit
boards and electronic components.
SObserve precautions for handling electrostatic--
sensitive devices.
SUse proper static--proof bags and boxes.
ESD
Component description
1MMC module.
1D1 LED, lights when the mains switch is on.
1D2 LED, lights when the thermal switches 15ST1 and / or 15ST2 are open due to
overtemperature.
2Mains module.
2AP1 Power supply board.
2L1 2 ferrite rings. The yellow/green cable must be wound two turns through the
ferrite rings.
2L2 Ferrite ring.
2QF1 Mains switch.
2XS1 Flat pin sockets. Important: to obtain a proper electrical connection, the
complete cord set must be replaced if the sockets have to be replaced.
15 Power module.
15AP1 Power board.
15AP2 Secondary board.
15C1 Smoothing capacitor, 1000 uF.
15D1 Diode module with rectifier and freewheel diodes.
15EV1 Fan.
15L1 Inductor.
15RS1 Shunt. 60 mV at 100 A.
15ST1 Thermal switch, fitted in the winding of main transformer 15TM1. See page 15.
15ST2 Thermal switch, fitted on the heat sink. See page 15.
15TM1 Main transformer.
20AP1 Controller circuit board.
20RP1 Potentiometer for setting of welding current.

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OrigoArc 150

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DESCRIPTION OF OPERATION
This description of operation describes the function of circuit boards and other components
in the power source. It is divided into sections, numbered to correspond to the circuit board
numbers and divisions into function blocks.
2AP1 Power supply board
The power supply board filters the mains voltage and generates internal supply voltages for
the machine.
2AP1:1 Interference suppressor circuit
WARNING! Dangerous voltage -- mains voltage.
The mains voltage is filtered by the power supply board. Power board 15AP1
rectifies the mains voltage.
2AP1:2 Primary and secondary circuit

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WARNING! Dangerous voltage -- mains voltage.
The primary circuit is supplied with 325 V DC from the power board, 15AP1.
S1 is a fuse with high rupturing capacity.
Transistor Q3 is the switching element in a switched voltage supply. The
secondary voltage, +24 V, is sensed by IC2 and controlled by IC1. It has a
tolerance of ±0.6 V.
The isolation voltage of transformer T1 and optocoupler IC3 is 4 kV.
2AP1 Component positions
WARNING! Dangerous voltage -- mains voltage.

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WARNING!
Dangerous voltage -- mains voltage.
Never make any measurements on this
board when the machine is connected to
the mains supply.
15AP1 Power board
The power module is a single forward converter, operating at a switching frequency of
65 kHz. IGBT transistors are used as the switching elements. See page 21 and 22 for
screen traces of waveforms and measurement instructions.
If the power board has failed, a replacement board must be mounted in accordance with the
instructions on page 23.
The power board carries the mains rectifier, the charging circuit, the switching circuit and the
gate circuit.
The mains rectifier and the switching transistors are integrated in a semiconductor module,
PM1, which is part of the power board.
Charging circuit
When the mains power supply is turned on, the rectified mains voltage charges smoothing
capacitor 15C1 via resistor R31. Thyristor TY1 short--circuits charge resistor R31 when the
machine is loaded. If TY1 did not conduct, resistor R31 would burn out when the power
source is on load.

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Supply to 2AP1
The board supplies power supply board 2AP1 with 325 V DC (pins F1 and F3, connector
15XS1).
Gate driver stages
Transformer TR1 is a gate driver transformer for galvanic isolation of the drive circuits from
controller board 20AP1. Fuses S10 and S20 protect the gate driver circuit if the IGBT
transistors fail.
Switching circuit
The switching transistors are integrated in the semiconductor module. They are parallel--
connected three and three.

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15AP1 Component positions
Pin positions of the semiconductor module

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15AP2 Secondary board
The secondary board is fitted on the main transformer 15TM1, diode module 15D1 and
inductor 15L1.
Diode module 15D1 comprises two diodes, rectifier and freewheel diode. During the time
interval between two voltage pulses from transformer 15TM1, the freewheel diode maintain
the welding current from inductor 15L1.
If the diode module has failed, a replacement module must be fitted in accordance with the
instructions on page 23.
Inductor L1 forms an LC circuit with C3//C4 and D1 to reduce the risk of arc extinction at low
welding currents. When rectifier diode 15D1 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 D1 prevents capacitor C3//C4 from going negative.
15AP2 Component positions

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20AP1 Control board
The control board monitors and controls the various functions of the power source.
If the board is faulty, it must be replaced. After replacing the board, soft--start the machine.
See the instructions on page 18.
20AP1:1 Power supply
Voltage regulator VR1 produces an output voltage of +20 ¦1.0 V. All circuits
on the control board, except the current reference, are supplied from VR1.
20AP1:2 Current reference input
The reference input is supplied with +5.1 V generated by IC3, the pulse width
modulator.
Potentiometer R1 adjusts the reference voltage from potentiometer 20RP1 for
correct maximum current value.
20AP1:3 Pulse width modulator

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The pulse width modulator determines the frequency and pulse duration of the
switch transistors’ control pulses. IC3 controls the pulse frequency, the pulse
time and inhibition of pulses.
The pulse frequency is 65 kHz +/--1 kHz, with a maximum pulse width of 42 --
44 % of the cycle width. See page 21 for screen traces of waveforms and
measurement instructions.
Transistor Q5 controls the primary winding of the pulse transformer on circuit
board 15AP1.
The reference voltage, +5.1 V, from IC3 is used as reference for the shunt
voltage and the current reference input.
20AP1:4 Temperature monitoring
The thermal overload switches, 15ST1 and 15ST2, are normally closed, which
means that input T2 is at about 9 V.
15ST2 opens at 85 _C, and is fitted on the heat sink. 15ST1 opens at 130 _C,
and is fitted in the winding of the main transformer, 15TM1.
If either of the switches operates, the power source is stopped and 1D2, the
yellow LED on the front panel lights. The power source cannot be restarted
until it has cooled sufficiently for the switch(es) to reclose.
20AP1:5 Shunt input
The shunt produces 60 mV at a welding current of 100 A. The shunt response
is linear to the welding current.
If the shunt is not connected to the circuit board, resistor R67 supplies about
0.6 to 0.9 V at the shunt input. This blocks the current control amplifier, i.e. the
machine does not deliver any welding current.
Note: the reference level for the shunt voltage is +5.1V, voltages mentioned
above are measured between terminals S1 and S2.

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20AP1:6 Arc voltage monitoring
The open--circuit voltage controller senses the voltage at the welding current
terminals and limits it to a level between 60 and 71 V. This function is inactive
during welding, i.e. when the shunt voltage is higher than 2.1 mV.
When the OrigoArc is in welding mode, the maximum output voltage is 110 V.
20AP1 Component positions

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SERVICE INSTRUCTIONS
What is ESD?
A sudden transfer or discharge of static electricity from one object to another. ESD stands for
Electrostatic Discharge.
How does ESD damage occur?
ESD can cause damage to sensitive electrical components, but is not dangerous to people.
ESD damage occurs when an ungrounded person or object with a static charge comes into
contact with a component or assembly that is grounded. A rapid discharge can occur,
causing damage. This damage can take the form of immediate failure, but it is more likely
that system performance will be affected and the component will fail prematurely.
How do we prevent ESD damage?
ESD damage can be prevented by awareness. If static electricity is prevented from building
up on you or on anything at your work station, then there cannot be any static discharges.
Nonconductive materials (e.g. fabrics), or insulators (e.g. plastics) generate and hold static
charge, so you should not bring unnecessary nonconductive items into the work area.
It is obviously difficult to avoid all such items, so various means are used to drain off any
static discharge from persons to prevent the risk of ESD damage. This is done by simple
devices: wrist straps, connected to ground, and conductive shoes.
Work surfaces, carts and containers must be conductive and grounded. Use only antistatic
packaging materials. Overall, handling of ESD--sensitive devices should be minimized to
prevent damage.
WARNING !
STATIC ELECTRICITY can damage circuit
boards and electronic components.
SObserve precautions for handling electrostatic--
sensitive devices.
SUse proper static--proof bags and boxes.
ESD
Special tools
Torx key
Torx key no. T10 and T25
Soft--starting tool SST 1
The soft--starting tool SST 1 is made for the CaddyArc, CaddyTig, OrigoTig and OrigoArc. It
can be ordered from ESAB, ordering no. 0459 534 880.
The tool includes: Soft starting rectifier, cable set, voltage test board, gate pulse load and
shunt voltage resistor for the OrigoArc.

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Soft starting
We recommend soft starting of the machine after replacing control circuit board 20AP1,
power supply board 2AP1 and circuit boards or components in the power module. Soft
starting supplies the power module with a low voltage in order to avoid injury to persons or
damage to components.
It is a good idea to use soft starting when fault tracing.
Special equipment
To soft--start the machine you need soft--starting tool SST 1, this is described on page 17.
Instructions
1. Disconnect wires 1501, 1502, 1503 and 1504 from circuit boards 2AP1 and 15AP1.
Disconnections prior to soft starting
2. Connect the 230 V AC input of the SST 1 to terminals B1 and B2 on circuit board
2AP1.
3. Connect the 325 V DC output of the SST 1 to terminals F1 and F3 on circuit board
2AP1.
The SST 1 connected to 2AP1
4. Disconnect connector 20XS4 from terminal PS of power supply board 2AP1. Connect
the voltage test cable of the SST 1 to terminal PS of power supply board 2AP1.
5. Connect the power source to the mains and turn on the mains switch.
6. Verify the output voltages from 2AP1, all LEDs must light.
(OrigoArc: only the +24V LED must light).
7. Switch off the machine. Disconnect the voltage test cable and reconnect connector
20XS4 to terminal PS of circuit board 2AP1.
8. Disconnect connector 15XS3 (supply to the fan) from terminal E of circuit board 2AP1.
Connect the 24 V DC input of the SST1 to terminal E of circuit board 2AP1.

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9. Connect the 24 V DC output of the SST 1 to terminals C1 and C2 of power board
15AP1.
Circuit connections and measuring points for soft starting
10. Switch on the machine and set it to MMA mode.
11. Check that the DC voltage across smoothing capacitor 15C1 is 22--24 V.
12. Check that the DC voltage at the welding terminals is 7--8 V.
13. If all the measurements are as described above, reconnect the wires to restore the
power source to normal operation mode and make a test weld.

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Checking rectifier and freewheel diodes
1. Disconnect the machine from the mains.
2. Dismantle the housing of the machine.
3. Use a Torx key no. T25 to unscrew and remove five screws from circuit board 15AP2.
The screws are marked on the picture below,
4. Bend out the circuit board so that it has no contact with the connections of the diode
module.
5. Use a multimeter in diode test position to measure the forward voltage drop of the two
diodes: see the picture below. The voltage drop must be 0.3 to 0.5 V.
6. If the diode module has to be replaced, follow the instructions on page 23.
Measuring points, circuit board 15AP2
Circuit diagram and measuring points, circuit board 15AP2