Caddy Arc 251i Service Manual

Caddyt

Arc 251i

Service manual

0740 800 188

090819

Valid for serial no. 810−xxx−xxxx

READ THIS FIRST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TECHNICAL DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WIRING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Component description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Arc 251i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DESCRIPTION OF OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 MMC unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2AP1 EMC board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2AP2 Power supply board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2AP2:1 Primary circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2AP2:2 Secondary circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2AP2 Component positions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15AP1 Power module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15AP1:1 Switching circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15AP1:2 Gate driver stages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15AP1:3 Secondary power circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15AP1:4 Temperature monitoring circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15AP1:5 Thyristor firing circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15AP1 Component positions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17AP1 PFC board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17AP1:1 Power supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17AP1:2 Power factor corrector (PFC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17AP1:3 Thyristor firing circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17AP1:4 Temperature monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17AP1 Component positions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20AP1 Control board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20AP1:1 Power supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20AP1:2 Control panel interface circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20AP1:3 Remote control input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20AP1:4 Pulse width modulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20AP1:5 Temperature monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20AP1:6 Shunt and current control amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20AP1:7 Arc voltage feedback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20AP1:8 TIG functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20AP1:9 Welding process control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20AP1:10 Power−up starting sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20AP1:11 Fan On/Off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20AP1 Component positions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20AP1 VRD strapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FAULT CODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SERVICE INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . What is ESD? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Service aid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Special tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Checking power board 15AP1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Checking PFC board 17AP1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Soft starting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Checking the gate pulses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mounting components on the heat sink . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IN−SERVICE INSPECTION AND TESTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . General requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Periodic inspection and test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . After repair, inspection and test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Visual inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Electrical test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Functional test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Test report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4 4 5 6 7 8 10 10 11 12 12 13 14 16 16 16 17 18 18 19 20 20 20 21 21 22 23 23 24 24 25 25 26 26 27 28 29 29 30 30 31 32 32 33 33 34 36 38 40 41 43 43 43 43 44 45 47 48

Rights reserved to alter specifications without notice.

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INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SAFETY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mains power supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Connections and control devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Overheating protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Power source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FAULT−TRACING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SPARE PARTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

49 49 49 49 49 50 50 50 50 51 51 51

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 wiring diagram as a form of index for the description of operation. The circuit boards are divided into numbered blocks, which are described individually in more detail in the description of operation. Component names in the wiring diagram are listed in the component description. Use the spare parts list as a guide to where the components are located in the equipment. The spare parts list is published as a separate document, see page 51. This manual contains details of design changes that have been made up to and including August 2009. The manual is valid for: Arc 251i with serial number 810−xxx−xxxx. The Arc 251i is designed and tested in accordance with international and European standards IEC/EN 60974. 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.

WARNING! Many parts of the power source are at mains voltage.

CAUTION! Read and understand the instruction manual before installing or operating.

INTRODUCTION Caddy Arc 251i is a welding power source intended for MMA and TIG welding, where all settings are made from the control panel.

Design structure of the power source Caddy Arc 251i is a microprocessor controlled power source based on the inverter principle. It consists of a number of function modules, as shown in the schematic diagram below. Each module has a module number, which is always included as the first part of the name/identification of components in the module.

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Principle block diagram of the Arc 251i

The modules have the following main functions: 2AP1 EMC module The EMC module suppresses interference to the mains. 17AP1 PFC The PFC module handles the power factor correction for the power source. The 3 phase voltage is rectified and feeds a switching circuit that forms a controlled high voltage DC supply to the power board, 15AP1. 15AP1 Power board This module is a forward inverter, operating at a switching frequency of 45 kHz. IGBT transistors are used as the switching elements. All power semiconductors are built into modules. 2AP2 Power supply unit The power supply unit (PSU) is supplied by the PFC module. It generates supply voltages to the fan, the control board and the switching circuit of the PFC module. 20AP1 Control board The control board, 20AP1, checks the status of the control elements of the control panel and controls the function of the power board, 15AP1.

TECHNICAL DATA Arc 251i Mains voltage Mains supply Primary current Imax MMA Imax TIG No−load power demand when in the energy−saving mode, 6.5 min. after welding Setting range MMA TIG Permissible load at MMA 30 % duty cycle 60 % duty cycle 100% duty cycle

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400 V $15%, 3∼ 50/60 Hz Ssc min 3.3 MVA 14 A 10 A 30 W 4 − 250 A 3 − 250 A 250 A / 30 V 190 A / 27.6 V 150 A / 26 V

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Arc 251i Permissible load at TIG 30 % duty cycle 60 % duty cycle 100% duty cycle Power factor at maximum current MMA TIG Efficiency at maximum current MMA TIG Open−circuit voltage without VRD with VRD Operating temperature Transportation temperature Constant sound pressure when idling Dimensions lxwxh Weight Insulation class transformer Enclosure class Application class

250 A / 20 V 190 A / 17.6 V 150 A / 16 V 0.94 0.93 83 % 79 % 62 V <35 V −10 to +40°C −20 to +55°C <70 db (A) 418 x 188 x 208 mm 10.5 kg H IP 23

Mains supply, Ssc min Minimum short circuit power on the network in accordance with IEC 61000−3−12 Duty cycle The duty cycle refers to the time as a percentage of a ten−minute period that you can weld at a certain load without overloading. The duty cycle is valid for 40°C. 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 diagram show to which module each component belongs. Wires/cables within modules are marked 100 − 6999. Wires/cables between modules are marked 7000 − 7999. Components outside modules − e.g. capacitors − are named such as C1 − C99, connectors XS1 − XS99 (S = socket), XT1 − XT99 (T = terminal). Circuit boards within each module have names such as 20AP1 − 20AP99.

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20 = module association, 1−69 AP = circuit board 1 = individual identification number, 0−99

Transistors within particular modules have identification numbers such as 15Q1 − 15Q99. 15 Q 1

= module association, 1−69 = transistor = individual identification number, 0−99

Component description Component

Description

1

MMC module. This module is described in separate manuals for the control panels.

2

Mains module. Wire numbers 200 − 299.

2AP1

EMC board, see page 11.

2AP2

Power supply board, see page 12.

2QF1

Main switch.

2L1 − 2L5

Ferrite ring cores.

15AP1

Power board, see page 16.

15AP2

LC−filter board, see page 17

15TM1

Main transformer

15L2

Inductor, welding circuit.

15ST1

Thermal switch in the winding of 15L2.

15D1 − 15D3

Diode modules Each module consists of two diodes. Two diodes are rectifier diodes, one from 15D1 and one from 15D2. Three diodes are frewheel diodes, one from each module. One diode from 15D3 is a filterdiode. See page 41 for assembly instructions.

15EV1

Fan.

15RS1

Shunt. 119 $1 mV at 250 A

17AP1

PFC board, see page 20.

17L1

PFC inductor

20AP1

Control board, see page 23.

CAUTION ! STATIC ELECTRICITY can damage circuit boards and electronic components.

ESD

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S

Observe precautions for handling electrostatic− sensitive devices.

S

Use proper static−proof bags and boxes.

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Arc 251i

Placement of the circuit boards

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DESCRIPTION OF OPERATION This description of operation describes the function of circuit boards and other components in the equipment. It is divided into sections, numbered to correspond to the circuit board numbers and divisions into function blocks.

1 MMC unit The MMC unit consists of a operator’s control panel and a display board. The MMC is used for setting and displaying welding data. The welding data are stored by the control board, 20AP1. The control panel consists of pushbuttons, control knob, LEDs and a 3−digit display. The control panels are described in separate instruction and service manuals. The control panels are: S

A32 intended for MMA− and DC TIG−welding

S

A34 intended for MMA− and DC TIG−welding.

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2AP1 EMC board The combination of coils and capacitors prevents interference from the inside of the machine to reach the electric mains network.

Circuit diagram

WARNING!, Dangerous voltage − mains voltage.

Component positions

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2AP2 Power supply board The power supply board receives rectified mains voltage, about 565 V DC, from the PFC board. From this it generates supply voltages for the power source.

2AP2:1

Primary circuit WARNING! Dangerous voltage − mains voltage.

The primary circuit is supplied at 565 V DC from the PFC board, 17AP1. Transistors Q1 and Q2 are the switching elements in a switched voltage supply. The sensing circuit uses the secondary voltage +24V that is connected to IC5. Through optocoupler IC2, IC5 controls switch regulator IC3, which generates gate pulses to Q1 and Q2, via TR1. +15VA and 0VA Internal power supply for the 2AP2 and for circuits on the 17AP1 and 15AP1. It is regulated to 15$0.75 V by VR3. It is part of the primary side as it shares the 0VA with the 565 V supply voltage.

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2AP2:2

Secondary circuit

The output voltages can be tested by the SST 3, see soft−starting on page 38. +13VB and 0VB Unregulated voltage at 13$1.5 V with galvanic isolation, used for remote control. +5V and 0V The voltage is regulated by VR1 to 5$0.25 V. +24V and 0V This voltage is regulated to 24$0.75 V by IC3 on the primary side togheter with IC5 on the secondary side. −15V and 0V This voltage is regulated to −15$0.75 V by VR4. Fan On/Off The fan, 15EV1, is supplied at +24V. It is controlled by 20AP1 with the signal Fan On/Off. See also “20AP1:11 Fan On/Off” on page 29. Early warning power shut down If the voltage goes low, the output CN1:8 generates a warning signal to the processor on the control board 20AP1. The control board AP201 then shuts down in a controlled manner.

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2AP2

Component positions

WARNING! Dangerous voltage − mains voltage. The shaded area is at mains voltage potential.

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emptypage

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15AP1 Power module

Power module main circuits

WARNING! Dangerous voltage − mains voltage. Never make any measurements on this board when the machine is connected to the mains supply. The power module is a single forward converter, operating at a switching frequency of 45 kHz with IGBT transistors as the switching elements. The power board carries the gate circuit and the switching circuit. The switching transistors are integrated in a semiconductor module, PM1, which is part of the power board. See page 40 for screen traces of waveforms and measurement instructions. On page 34 there are instructions on how to check the power board. If the power board has failed, a replacement board must be mounted in accordance with the instructions on page 41.

15AP1:1

Switching circuit The switching transistors are integrated in the semiconductor module, PM1. They are connected in parallel four and four.

15AP1:2

Gate driver stages Transformer TR1 is a gate driver transformer for galvanic isolation of the drive circuits from circuit board 20AP1. The gate pulses are measured on circuit board 20AP1, see instructions on page 40.

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15AP1:3

Secondary power circuits

The secondary power circuits are: transformer 15TM1, diode modules 15D1,15D2,15D3, inductor 15L2 and LC filter 15AP2. Diode modules Each diode module consists of two diodes. Two diodes are rectifier diodes, one from 15D1 and one from 15D2. Three diodes are frewheel diodes, one from each module. One diode from 15D3 is a filterdiode. During the time interval between two voltage pulses from transformer 15TM1, the freewheel diodes maintain the welding current from inductor 15L2. If a diode module has failed, a replacement module must be fitted in accordance with the instructions on page 41. 15AP2 Filter board Inductor L1 forms an LC circuit with C1//C2 and D2 to reduce the risk of arc extinction at low welding currents. When rectifier diodes 15D1//15D2 conducts, the LC circuit charges up. The circuit is capable of temporarily maintaining a high arc voltage at low current.

15AP2, circuit diagram and component positions

Diode D2 prevents capacitor C1//C2 from going negative.

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15AP1:4

Temperature monitoring circuits

WARNING! Dangerous voltage − mains voltage. +15VA, +14VA, +5V1A and 0VA are at mains voltage potential. The control board, 20AP1, uses a digital input to monitor the temperatures of the power source. The temperature feedback from the NTC resistors on the PFC and power boards is analogue. The monitoring circuits on the power board handles the threshold levels and hysteresis of the temperature measument. See also “20AP1:5 Temperature monitoring” on page 25.

15AP1:5

Thyristor firing circuit See “17AP1:3 Thyristor firing circuit” on page 21.

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15AP1

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Component positions

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17AP1 PFC board The PFC board consists of the main rectifier, the thyristor firing circuit, the temperature circuit and the PFC control circuit. If the PFC board has failed, a replacement board must be mounted in accordance with the instructions on page 42. On page 36 there are instructions on how to check the PFC board. WARNING! Dangerous voltage − mains voltage. All parts of this circuit board are at mains voltage potential.

17AP1 main circuits

17AP1:1

Power supply The three−phase mains voltage is rectified by semiconductor module PM1. When the power source is in idle mode, the rectified voltage (565 V) is supplied through the charging resistors, R78 and R79. In welding mode the thyristor in PM1 by−passes the resistors. If the thyristor did not conduct, resistors R78 and R79 would burn out when the unit is in welding mode. The 565 V supplies the PFC circuit that boosts the voltage to 710 V.

17AP1:2

Power factor corrector (PFC) The aim with the power factor corrector is to keep the mains current in phase with the mains voltage. The PFC circuit holds the intermediate voltage (+DCbus) at 710 V. If the PFC circuit does not work the intermediate voltage is 565 V or less. When the PFC is working properly, the voltage across the DCbus is 710 V.

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17AP1:3

Thyristor firing circuit

When the mains power supply is turned on and during idle mode the thyristor in PM1 is off. When the switching circuit on power board 15AP1 receives gatepulses from the control board, the firing circuit turns on the thyristor in PM1 so that it by−passes the charging resistors.

17AP1:4

Temperature monitoring

The PM1 module havs a built−in NTC−resistor that monitors the internal temperature. It is connected to the temperature circuits on the power board. See “15AP1:4 Temperature monitoring” on page 18 and “20AP1:5 Temperature monitoring” on page 25.

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17AP1

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Component positions

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20AP1 Control board The processor on the control board monitors and controls the various functions of the power source. It obtains information on welding data from the control panel. If the circuit board is faulty, it must be replaced. After replacing the circuit board, soft−start the machine. See the instructions on page 38. Note! There are jumpers on the board that must be moved to the replacement board, see page 30.

20AP1:1

Power supply +5 V and +2.5 V

IC6 monitors the 24 V voltage supply to the 5 V regulator on circuit board 2AP2. IC16 monitors the 5 and 2.5 V supplies. Regulator VR4 supplies the processor with +2.5 V. The voltage on terminal PF6 is normally about 24 V, when this drops below 20 V, pin 14 of IC6 goes low, providing the processor with a low power supply voltage signal. The processor then stores current data and generates fault code E4. When the 5 and 2.5 V voltages are passing below their treshold values, the processor receives a reset signal from IC16. Fault code E4 is not displayed at normal power off +15 V and +20 V

Voltage regulator VR2 produces an output voltage of +20 $1.0 V, which supplies the pulse width modulator output stage. Voltage divider R70/R75 supplies 2.6 V to the processor. This provides a signal that the power supply is available. Voltage regulator VR1 produces an output voltage of +15 V, and this, together with the −15 V supply, powers the analogue circuits.

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−15 V

The −15 V power supply is monitored by the processor. +10 VB

Voltage regulator VR3 produces a stabilised +10 V supply, which is used to supply the remote control unit. This supply is referred to as +10 VB, and its neutral point, 0 VB, is separated from the electronic neutral (0 V). Potentiometer R56 is used to adjust the voltage.

20AP1:2

Control panel interface circuits See the service manual for the A32/A34 control panels.

20AP1:3

Remote control input

If the remote control input is activated, but there is no reference signal, resistor R54 holds the reference input low. This results in a welding current of 3 A for TIG welding and 4 A for MMA welding.

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20AP1:4

Pulse width modulator

The pulse width modulator determines the frequency and pulse time of the switching transistors’ control pulses. IC3 controls the pulse frequency, the pulse time and inhibition of pulses. The pulse frequency is 45 kHz +/− 1kHz, with a maximum pulse width of 43 − 44 % of the cycle width. See page 40 for screen traces of waveforms and measurement instructions. Transistor Q5 controls the primary winding of the pulse transformer on circuit board 15AP1.

20AP1:5

Temperature monitoring

Principle diagram of the temperature monitoring circuits

The temperature monitoring circuit operates when the temperature exceeds one of the threshold temperatures as decribed below. If the monitoring circuit operates, the power source is stopped. The power source cannot be restarted until it has cooled sufficiently. 15NTC_PM1 is fitted inside semiconductor module PM1 of the power board, 15AP1. The treshold temperature is 95_C and it resets at 62_C. 17NTC_PM1 is fitted inside semiconductor module PM1 of the PFC board, 17AP1. The treshold temperature is 88_C and it resets at 60_C. Thermal overload switch 15ST1 is fitted in the winding of inductor 15L2. It opens at 140_C.

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20AP1:6

Shunt and current control amplifier

The shunt produces 119 mV at a welding current of 250 A. The shunt response is linear to the welding current. If the shunt is not connected to the circuit board, resistor R2 supplies about 1.4 to 1.9 V to the shunt input. This blocks the current control amplifier, i.e. the machine does not deliver any welding current.

20AP1:7

Arc voltage feedback

This circuit measures and scales the arc voltage to a suitable level for the processor. 64 V arc voltage produces a voltage signal of 5.0 V at the cathode of diode D13. Open−circuit voltage control The open−circuit voltage control holds the voltage at 50 − 64 V. When the VRD (Voltage Reduction Device) function is active, the open−circuit voltage is < 35 V (19 − 30 V). The VRD function can only be activated or deactivated by changing the strapping of the control board, see the circuit diagram below and the component positions diagram on page 30. Note! Spare part boards are delivered with VRD inactive. VRD strapping

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MMA S The machine generates the actual open−circuit voltage, see: “Open−circuit voltage control” above. S Touch the electrode on to the workpiece. When the open−circuit voltage goes below 45 V (16 V when VRD is active), the open−circuit voltage control is disabled. S When the current exceeds 8 A the hot start current is activated. S When the arc voltage exceeds 52 V, welding stops and the open−circuit voltage control is activated. When the welding arc extinguishes the open circuit voltage is about 120 V, peak voltage. Within 0.3 seconds the open−circuit voltage control reduces the voltage to about 60 V, peak voltage, (30 V when VRD is active). TIG See: “20AP1:8

20AP1:8

TIG functions” below.

TIG functions Live TIG start S The machine generates the actual open−circuit voltage, see: “Open−circuit voltage control” above. S Touch the electrode on to the workpiece. The machine produces a current of about 24 A. S Lift the electrode from the workpiece. The arc strikes, the open−circuit voltage control is deactivated and the current increases to 30 A. S When the arc voltage exceeds 8 V, the current increases / decreases to the set current. S If the arc voltage is above 45 V for more than 100 milliseconds the open−circuit voltage control is activated. When the welding arc extinguishes the open circuit voltage is about 120 V, peak voltage. Within 0.3 seconds the open−circuit voltage control reduces the voltage to about 60 V, peak voltage, (30 V when VRD is active). Terminal TIG

Terminal TIG, shown above, is not used in this application. Terminals TIG1 and TIG5 are used for power supply during soft−starting, see page 38.

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20AP1:9

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

Current

Hot start MMA Peak current Adjustable starting current Set current

1 2 Starting current, MMA welding mode 1. Phase 1, fixed starting current depending on the set current. 2. Phase 2, hot start = adjustable starting current.

Time

MMA normal welding mode In the MMA normal welding mode, the welding current is briefly increased at the start of welding. The peak current, phase 1 in the diagram above, is engaged for 150 milliseconds. The peak current is twice the normal welding current up to 150 A (i.e. twice the set value), subject to a maximum of 350 A. The hot start current, phase 2 above, is engaged for 1.5 seconds. It is set in per cent of the set current, but does never exceed the peak current. MMA drop welding mode In the MMA drop welding mode, the peak current is three times the set value, but the duration is shorter at only 50 ms. The hot start current, phase 2 above, is engaged for 240 milliseconds. It is set in per cent of the set current, but does never exceed the peak current.

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20AP1:10 Power−up starting sequence On power−up, the board’s CAN controller reads in the bus speed from the micro processor: 400 kbit/s. The circuit board displays the starting sequence from power−up. LED1 lights red. Then LED1, LED2 and LED3 lights green. When the board has been initiated, and the power source is in the application program, LED1 flashes continously with a green light. LEDs on circuit board 20AP1

20AP1:11 Fan On/Off

The fan is controlled by the control signal Fan On/Off. The signal is connected to a power transistor on 2AP2 that switches the power to the fan on or off. See also “Fan On/Off” on page 13. The fan starts when the mains switch is turned on and runs for seven seconds. It starts when welding starts and continues to run six and a half minutes after welding is finished.

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20AP1

Component positions

Note! There must be a jumper between pin 5 and 6 on terminal RS.

20AP1

VRD strapping Strap terminal A1 and A2 to activate the VRD function. Strap terminal A2 and A3 to deactivate the VRD function. See also item 20AP1:7 Arc voltage feedback on page 26.

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FAULT CODES Code Description E04

5 V power supply too low The unregulated power supply voltage (+24 V) is too low: the smoothing capacitors cannot keep the voltage up enough for the processor to continue to operate. The processor stops all normal activities, expecting to be shut down. Action: Turn off the mains power supply to reset the unit. If the fault persists, check the power supply to circuit board 20AP1.

E06

High temperature The temperature monitoring circuit has operated. The power source is stopped, and cannot be restarted until the circuit has reset. See also page 25. Possible causes: Overloading, fan not working properly, cooling air inlets or outlets blocked or obstructed or dirt on the heat exchanger.

E11

Current servo fault Automatic reset when the fault has cleared. May also be reset by pressing any pushbutton.

E16

High no−load voltage, VRD error The open circuit voltage is too high. Action: Turn off the mains power supply to reset the unit. Check the arc voltage monitoring circuits, see diagram on page 26. If the fault persists replace circuit board 20AP1.

E19

Error in persistent memory Action: Restart the machine. If the fault persists, replace circuit board 20AP1.

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SERVICE INSTRUCTIONS

CAUTION ! 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.

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.

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Service aid We can offer a number of service tools that will simplify the service.

Antistatic service kit Ordering no. 0740 511 001 The kit makes it easier to protect sensitve components from electrostatic discharge. Contents: S

A conductive mat (size 610 x 610 mm)

S

A 1.5 metre long ground cable with a crocodile clip

S

An adjustable wrist strap and cable with an inbuilt protective resistor

Antistatic service kit

Special tools Soft−starting tool SST 3 The soft−starting tool SST 3 is made for ESAB’s single phase inverters and for 3−phase inverters with 250 A output current. Ordering no. 0459 534 881 Functions for single phase inverters S Soft−starting rectifier S Voltage adapter with current limit S Voltage−test board S Gate pulse load with test terminals S Shunt voltage resistor. For single phase inverters with analogue control board: Arc 151i A31, Arc 152i A31 and OrigoArc

Functions for 3 phase inverters S Voltage adapter with current limit S Voltage−test board S Gate pulse load with test terminals S Temperature monitoring override jumper

Test box TB 1 To be used for in−service inspection and testing. Ordering no. 0460 868 880

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Checking power board 15AP1 1.

Disconnect the welding power source from the mains supply.

2.

Dismantle the cover.

3.

Measure the forward voltage drop of the freewheel diodes in the PM1 module.

4.

5.

a.

Connect the positive pole of the multimeter to CN4 and the negatve pole to CN5. The voltage drop must be 0.35 to 0.6 V.

b.

Connect the positive pole of the multimeter to CN6 and the negatve pole to CN3. The voltage drop must be 0.35 to 0.6 V.

Measure the resistance across gate and source of the transistors in the PM1 module. a.

Connect the negative pole of the ohmmeter to CN5 and the positive to PM1:9, PM1:10, PM1:12 and PM1:13 respectively. The resistance must be higher than 100 kohm.

b.

Connect the negative pole of the ohmmeter to CN4 and the positive to PM1:18, PM1:19, PM1:21 and PM1:22 respectively. The resistance must be higher than 100 kohm.

Measure the resistance of the NTC−resistor in PM1. Measure between PM1:23 and PM1:24. The resistance must be 1.5 to 2.0 kohm at an ambient temperature of about 20C.

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Measuring points for 15AP1

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Checking PFC board 17AP1 1.


2.


3.

Measure the forward voltage drop of the diodes of the rectifier bridge. The voltage drop must be 0.4 to 0.6 V.

4.

a.

Connect the negative pole of the multimeter to R78 and the positive pole to CN1, CN4 and CN6 respectively.

b.

Connect the positve pole of the multimeter to CN3 and the negative pole to CN1, CN4 and CN6 respectively.

Unscrew and remove the two screws that are connecting 17L1 to the circuit board. Insulate the terminals of 17L1 from the circuit board by fitting the tip of a plastic cable tie, or similar, between the connection terminals of 17L1 and the circuit board. a.

Measure the forward voltage drop of diode PM1:D1. Connect the positve pole of the multimeter to R79 and the negative pole to CN2. The voltage drop must be 0.4 to 0.6 V.

b.

Measure the forward voltage drop of diode PM1:D2. Connect the positve pole of the multimeter to 17L1 and the negative pole to CN2. The voltage drop must be 0.7 to 0.9 V.

5.

Connect 17L1 to the circuit board, tighten the connection screws to a torque of 4.5 Nm.

6.

Measure the resistance across the charge resistors R78 and R79. The resistance must be about 24 ohm.

7.

Measure the resistance of the NTC−resistor in PM1. a.

Measure between PM1:5 and PM1:6. The resistance must be 1 to 2 kohm at an ambient temperature of about 20C.

b.

Disconnect the ribbon cable from terminal CN5.

c.

Measure between PM1:5 and PM1:6. The resistance must be 5.5 to 6.5 kohm at an ambient temperature of about 20C.

d.

Reconnect the ribbon cable to terminal CN5.

8.

Connect the power source to the mains and switch it on.

9.

Measure the rectified mains voltage. Measure between R79 and CN3. The voltage must be 565 V DC ("15%).

10. Measure the output voltage from the PFC board. Measure between CN2 and CN3. The voltage must be 710 V DC ("5%). 11. Checking the thyristor firing circuit. a.

Connect a voltmeter across R78 and R79. The voltage at no load must be about 1.2 V DC.

b.

Connect the output of the power source to a resistive load of 200 ohm 100 W (test box TB 1 can be used).

c.

Set a welding current of 25 A. The voltage across R78 and R79 must be about 0.8 V DC.

12. Checking voltage 5V1. Measure between TP1 and CN3. The voltage must be 5.1 V DC ("2%). 13. Disconnect the power source from the mains. 14. Reassemble the cover.

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Measuring points for 17AP1

The circuit diagram of 17AP1 is on page 20.

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Soft starting

We recommend soft starting of the machine after replacing circuit board 20AP1, power supply board 2AP2 and circuit boards or components in the power module. Soft starting supplies the power board 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 the soft−starting tool SST 3, this is descrived on page 33. WARNING! Dangerous voltage − The PFC board, 17AP1, is at mains voltage during the soft−starting procedure. Placement of the circuit boards

Instructions 1.


2.


3.

Remove the two copper bars between the PFC board, 17AP1 and the power board, 15AP1. (Connections 17AP1:CN2 to 15AP1:CN5 and 17AP1:CN3 to 15AP1:CN6.)

4.

Disconnect the ribbon cable from terminal CN1 of the power supply board, 2AP2.

5.

Connect the cable “Voltage test” from SST 3 to terminal CN1 of 2AP2.

6.

Connect the power source to the mains supply.

7.

Turn the mains switch to ON.

8.

Verify the output voltages from 2AP1, all LEDs on the SST 3 must light.

9.

Check the +15VA voltage from 2AP2. Measure between terminals CN2:4 and CN2:5 on 2AP2. The voltage must be 15 V "0.75 V.

WARNING! Terminal CN2 is at mains voltage

10. Turn the mains switch to OFF. 11. Reassemble the ribbon cable between the power supply board and the control board. 12. Disconnect the power source from the mains supply.

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13. Connect SST 3 for soft starting of 15AP1. a.

Connect cable 20AP1 TIG to terminal TIG of the control board.

Connection of the SST 3 to the control board

b.

Connect cable 15AP1 CN5 to terminal CN5 of the power board.

c.

Connect cable 15AP1 CN6 to terminal CN6 of the power board. Connection of the SST 3 to the power board

14. Connect the power source to the mains supply. 15. Turn the mains switch to ON. 16. Set the power source to MMA mode. 17. Measure the supply voltage to 15AP1. Measure between CN5 (+) and CN6 (−). The voltage must be 22 to 25 V DC. 18. Measure the voltage across the welding outlets. The voltage must be about 4 V DC.

Circuit connections and measuring points for soft starting

19. Turn the mains switch of the welding power source to OFF. 20. Disconnect the power source from the mains supply. 21. Disconnect SST 3. 22. Reassamble the two copper bars between the PFC board and the power board. (Connections 17AP1:CN2 to 15AP1:CN5 and 17AP1:CN3 to 15AP1:CN6.) 23. Reassemble the cover.

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Checking the gate pulses When checking the gate pulses, the machine can either be in soft−starting mode or in normal operation mode.

Special equipment To measure the gate pulses, you need a gate pulse load. This is included in soft−starting tool SST3, which is described on page 33.

Instructions 1.

Disconnect the machine from the mains.

2.

Disconnect connector 20XS5 from terminal G on control board 20AP1.

3.

Connect the gate pulse test cable of the SST 3 to terminal G on control board 20AP1.

4.

Disconnect connector 20XS1 from terminal T on control board 20AP1.

Measuring connection for the gate pulses

5.

Connect the temperature−switch jumper to terminal T on control board 20AP1.

6.

Switch on the machine.

7.

Connect an oscilloscope to the SST 3, with the probe to terminal G2 and the screen to terminal G1 of SST 3.

8.

Set the machine to MMA welding mode.

9.

Measure the pulse frequency. It must be 45 kHz +/− 1kHz.

10. Measure the duration of the negative pulse. It must be 41 − 43 % of the cycle time, measured at a voltage level of −10 V. 11. The waveform of the pulses must be as shown below.

Gate pulses from circuit board 20AP1

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Mounting components on the heat sink Thermal paste Apply thermal conducting paste to the components before fitting them to the heat sink. Start by cleaning the heat sink, and then apply a very thin, even layer of thermal paste to the contact surfaces of the components. The purpose of the paste is to fill out any hollows in the surfaces of the components and the heat sink. Those parts of the component and the heat sink that are in true metallic contact may already have good thermal contact. Mount the components as described below. See the spare parts list for the order number for thermal paste, roller and roller handle. Use only the paste recommended by us.

Fitting instructions 15AP1

Power board with semiconductor module 1.

Clean the heat sink and apply thermal conducting paste to the semiconductor module as described above.

2.

Fit the board and tighten the screws to a torque of 2.5 Nm, and then further tighten them to 4.5 Nm.

3.

Tighten the screws that connect transformer 15TM1 and copper bars to circuit board 15AP1 to a torque of 4.5 Nm. CAUTION! Incorrectly fitted components can cause failure. Do not tighten the screws to more than 4.5 Nm. Note! If transformer 15TM1 has to be replaced, the power board must be removed and then refitted as described above.

15D1, 15D2, 15D3

Diode modules 1.

Clean the heat sink and apply thermal conducting paste to the diode module as described above.

2.

Fit the module and tighten the screws to a torque of 2.5 Nm, and then further tighten them to 4.5 Nm.

3.

Tighten all connections to the copper bars and circuit board 15AP1 to 4.5 Nm. CAUTION! Incorrectly fitted components can cause failure. Do not tighten the screws to more than 4.5 Nm.

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17AP1

PFC board with semiconductor module 1.

Clean the heat sink and apply thermal conducting paste to the semiconductor module as described above.

2.

Fit the board and tighten the screws to a torque of 2.5 Nm, and then further tighten them to 4.5 Nm.

3.

Tighten the screws that connect 17L1 and the copper bars to circuit board 15AP1 to a torque of 4.5 Nm. CAUTION! Incorrectly fitted components can cause failure. Do not tighten the screws to more than 4.5 Nm.

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IN−SERVICE INSPECTION AND TESTING in accordance with IEC 60974−4.

General requirements Qualification of test personnel Tests of welding power sources can be hazardous and shall be carried out by an expert in the field of electrical repair, preferably also familiar with welding, cutting and allied processes. Test conditions Tests shall be carried out at an ambient air temperature between 10 and 40 Measuring instruments The accuracy of measuring instruments shall be class 2.5 as a minimum, except for the measurement of insulation resistance, where the accuracy of the instruments is not specified but shall be taken into account for the measurement. The voltmeter shall have an internal resistance of at least 1M

Periodic inspection and test Periodic inspection and test shall be carried out in accordance with manufacturers instructions and local regulations. The periodic inspection and test consists of: S

Visual inspection, (see Visual inspection, page 44)

S

Electrical test (see Electrical test, page 45)

The inspection and test shall be documented in a test report, (see Test report, page 48). A signed and dated label shall be attached to the equipment after an approved test.

After repair, inspection and test After repair, inspection and test shall be carried out according to manufacturers instructions and local regulations. The after repair, inspection and test consists of: S

Visual inspection, (see Visual inspection, page 44)

S

Electrical test (see Electrical test, page 45)

S

Functional test (see Functional test, page 47)

The inspection and test shall be documented in a test report, (see Test report, page 48). A signed and dated label shall be attached to the equipment after an approved test.

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Visual inspection Disconnect the welding power source from the mains supply. During visual inspection, each safety related function judged as relevant by the test personnel, shall be checked for correct operation. During visual inspection, the following listed items shall be checked: 1.

2.

3.

4.

5.

Torch/electrode holder, welding current return clamp. S

missing or defective insulation

S

defective connections

S

defective, damaged switches

S

other damage

Mains supply S

defective, damaged cable

S

deformed, faulty plug

S

broken or thermally damaged plug pins

S

ineffective cable anchorage

S

cables and plugs unsuitable for the intended use and performance

Welding circuit S

defective damaged cable

S

deformed, faulty or thermally damaged coupler/sockets

S

ineffective cable anchorage

S

cables and coupler unsuitable for the intended use and performance

Enclosure S

missing or damaged parts

S

unauthorised modifications

S

cooling openings blocked or missing air filters

S

signs of overload and improper use

S

missing or defective protective covers

S

missing or defective lifting means, holder etc

S

conductive objects placed in the enclosure

Controls and indicators S

6.

defective switches, meters and lamps

General condition S

poor legibility of markings and labelling

S

other damage or signs of improper use

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Electrical test 1.


2.

Check continuity of the protective circuit. Measure the resistance of the protective circuit from the screw (1) to the protective earth connection in the the mains plug (2). During the measurement the cable shall be bent, flexed and twisted along the whole length in order to detect interuptions in the protective conductor. S

3.

Check the insulation resistance with an insulation tester with the measurement voltage set to 500 VDC. a.

Turn the mains switch of the the welding power source to ON.

b.

Measure from the supply pins in the mains plug (2) to the welding outlets (3,4). S

c.

d.

Required value not less than 2.5 MÙ

Measure from the supply pins in the mains plug (2) to the protective earth connection in the mains plug (2). S

e.

Required value not less than 5 MÙ

Measure from the welding outlets (3,4) to the protective earth connection in the mains plug (2). S

4.

Required value for cables up to 5 m, max 0.3 Ù

Required value not less than 2.5 MÙ

Turn the mains switch of the the welding power source to OFF.

Check the no−load voltage. Use the ESAB test box TB 1. If the welding power source has an activated VRD function then proceed to step 5. a.

Connect the positive (3) and negative (4) welding outlets to the positive and negative terminals (DCIN) of the TB 1.

b.

Connect a voltmeter to VPEAK of the TB 1.

c.

Connect the welding power source to the mains supply.

d.

Turn the control knob of the TB 1 anti−clockwise to 0.2.

e.


f.

Set the welding current control on the welding power souce to maximum.

g.

Slowly turn the control knob of the TB 1 clockwise from 0.2 to 5.2 while checking the voltmeter for the highest value. S

5.

Measured value shall not exceed the allowable value 113 VPEAK

h.


i.


Check of no−load voltage with the VRD activated. Use the ESAB test box TB 1. This test is only conducted when the VRD function is activated.

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a.

Connect the positive (3) and negative (4) welding outlets to the positive and negative terminals (DCIN) of the TB 1.

b.

Connect a voltmeter to VPEAK of the TB 1.

c.

Connect the welding power source to the mains supply.

d.

Turn the control knob of the TB 1 anti−clockwise to 0.2.

e.


f.

Set the welding current control on the welding power souce to maximum.

g.

Check the voltage with the voltmeter. S

Measured value shall not exceed 35 V.

h.

Check that the LED indicates active VRD function by a steady green light.

i.


j.


Test box TB 1

Circuit diagram of the TB 1

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Functional test 1.

Each safety related function judged as relevant by the test personnel shall be checked for correct operation. Conformity shall be checked by operating the device and by checking whether the welding power source operates correctly.

2.

Check the supply circuits on/off switching device a.


b.

Remove the cover

c.


d.

Measure from the supply pins of the mains plug to the EMC board, 2AP1. Measure L1−CN2:3. Required value, open circuit

S

Measure L2−CN2:1. Required value, open circuit

S

Measure L3−CN2:5. Required value, open circuit

e.


f.

Measure from the supply pins in the mains plug to the EMC board 2AP1.

g. 3.

S

S

Measure L1−CN2:3. Required value, less than 0.5

S


S


Reassemble the cover.

Check signal and control lamps Check the function of the display indicators by turning on the unit and visually check the front panel. The LED test starts with all LEDs dark, then the diodes are turned on and off, one at a time, until all diodes have been tested. If the test detects a fault, no fault code will be logged. Then the display test is made in the same way as the LED test but for each segment of the digits in the display. If the test detects a fault, no fault code will be logged. Finally the software version of the welding data unit is displayed.

4.

Check the function of the welding power source by welding.

5.


6.

Write the test report. See Test report, page 48).

7.

If the unit passes all the tests, attach appropriate label with signature and date of the test.

ch34_test

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S0740 800 188/E090819/P52

Test report Company:

Location:

Equipment: Arc welding power source Manufacturer: ESAB Testing equipment:

Serial number: Type:

PASSED

VISUAL INSPECTION ELECTRICAL TEST Protective conductor resistance Insulation resistance Input circuit/ Welding circuit (500 VDC)

Limit ≤ 0.3 Ω

ÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉ ÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉ ≥ 5 MΩ

Welding circuit/ Protective circuit (500 VDC)

≥ 2.5 MΩ

Input circuit/ Protective circuit (500 VDC)

≥ 2.5 MΩ

No−load voltage without VRD

Measured values

ÉÉÉÉ ÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉ ÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉ Vpeak

≤113 VDC

with VRD activated

Vpeak ≤35 VDC

Electrical test

PASSED

FUNCTIONAL TEST

PASSED

Remarks

Date Tested by

Signature

Testing company

cz01_testreport

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INSTRUCTIONS This chapter is an extract from the instruction manual for the Arc 251i.

SAFETY CAUTION! Read and understand the instruction manual before installing or operating.

INSTALLATION Location Place the power source so that its cooling air inlets and outlets are not obstructed.

Mains power supply Note! Mains supply requirements High power equipment may, due to the primary current drawn from the mains supply, influence the power quality of the grid. Therefore connection restrictions or requirements regarding the maximum permissible mains impedance or the required minimum supply capacity at the interface point to the public grid may apply for some types of equipment (see technical data). In this case it is the responsibility of the installer or user of the equipment to ensure, by consultation with the distrubution network operator if necessary, that the equipment may be connected.

Make sure that the welding power source is connected to the correct supply voltage and that it is protected by the correct fuse rating. A protective earth connection must be made in accordance with regulations.

Recommended fuse sizes and minimum cable area 400V

Mains voltage Mains cable area

mm2

Phase current I1eff

4 G 1.5 8A

Fuse anti−surge type C MCB

10 A 10 A

NOTE! The cable area and fuse rating above comply with Swedish regulations. Use the welding power source in accordance with the relevant national regulations.

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S0740 800 188/E090819/P52

OPERATION Connections and control devices 1

Mains voltage switch

4

Connection for remote control unit

2

Connection (+) MMA: welding cable or return cable TIG: return cable

5

Control panel, see separate instruction manual

3

Connection (−) MMA: return cable or welding cable TIG: torch

Overheating protection The welding power source has overheating protection that operates if the temperature becomes too high. When this occurs the welding current is interrupted and a fault code is displayed on the control panel. The overheating protection resets automatically when the temperature has fallen.

MAINTENANCE Regular maintenance is important for safe, reliable operation. Only those persons who have appropriate electrical knowledge (authorized personnel) may remove the safety plates.

CAUTION! All guarantee undertakings from the supplier cease to apply if the customer himself attempts any work in the product during the guarantee period in order to rectify any faults.

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S0740 800 188/E090819/P52

Power source Check regularly that the welding power source is not clogged with dirt. How often and which cleaning methods apply depend on: S

the welding process

S

arc times

S

placement

S the surrounding environment. It is normally sufficient to blow down the power source with dry compressed air (reduced pressure) once a year. Clogged or blocked air inlets and outlets otherwise result in overheating.

FAULT−TRACING Try these recommended checks and inspections before sending for an authorized service technician. Type of fault No arc.

Corrective action S S S S

The welding current is interrupted during welding.

S S

The thermal cut−out trips frequently.

S S

Poor welding performance.

S S S

Check that the mains power supply switch is turned on. Check that the welding current supply and return cables are correctly connected. Check that the correct current value is set. Check the mains power supply fuses. Check whether the thermal cut−outs have tripped (a fault code is displayed on the control panel). Check the mains power supply fuses. Make sure that you are not exceeding the rated data for the welding power source (i.e. that the unit is not being overloaded). Check that the welding power source is not clogged with dirt. Check that the welding current supply and return cables are correctly connected. Check that the correct current value is set. Check that the correct electrodes are being used.

SPARE PARTS The spare parts list is published in a separate document that can be downloaded from the internet: www.esab.com Product Arc 251i

ch34i1

Filename 0459 839 021

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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 2 745 11 28 THE CZECH REPUBLIC ESAB VAMBERK s.r.o. Vamberk Tel: +420 2 819 40 885 Fax: +420 2 819 40 120 DENMARK Aktieselskabet ESAB Herlev 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: +49 212 298 218 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. Amersfoort Tel: +31 33 422 35 55 Fax: +31 33 422 35 44

NORWAY AS ESAB Larvik Tel: +47 33 12 10 00 Fax: +47 33 11 52 03 POLAND ESAB Sp.zo.o. Katowice Tel: +48 32 351 11 00 Fax: +48 32 351 11 20 PORTUGAL ESAB Lda Lisbon Tel: +351 8 310 960 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. Alcalá de Henares (MADRID) Tel: +34 91 878 3600 Fax: +34 91 802 3461 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 ARGENTINA CONARCO Buenos Aires Tel: +54 11 4 753 4039 Fax: +54 11 4 753 6313

Asia/Pacific CHINA Shanghai ESAB A/P Shanghai Tel: +86 21 2326 3000 Fax: +86 21 6566 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 0188 Fax: +62 21 461 2929 JAPAN ESAB Japan Tokyo Tel: +81 45 670 7073 Fax: +81 45 670 7001 MALAYSIA ESAB (Malaysia) Snd Bhd USJ Tel: +603 8023 7835 Fax: +603 8023 0225 SINGAPORE ESAB Asia/Pacific Pte Ltd Singapore Tel: +65 6861 43 22 Fax: +65 6861 31 95

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 LLC ESAB Moscow Tel: +7 095 543 9281 Fax: +7 095 543 9280 LLC ESAB St Petersburg Tel: +7 812 336 7080 Fax: +7 812 336 7060

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 Kyungnam Tel: +82 55 269 8170 Fax: +82 55 289 8864 UNITED ARAB EMIRATES ESAB Middle East FZE Dubai Tel: +971 4 887 21 11 Fax: +971 4 887 22 63

BRAZIL ESAB S.A. Contagem−MG Tel: +55 31 2191 4333 Fax: +55 31 2191 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 57 48

ESAB AB SE−695 81 LAXÅ SWEDEN Phone +46 584 81 000 www.esab.com 081016

Caddy Arc 251i Service Manual

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