ESAB LTS 320 User manual

0740 801 012

020311

LTP 450

LTS 320

Protig 450 / Prowelder 320

Service manual

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LIST OF CONTENTS Page

READ THIS FIRST 3.......................................

WARNING 4..............................................

COMPONENT DESCRIPTION 5.............................

CONNECTION DIAGRAM LTP 450 8........................

CONNECTION DIAGRAM LTS 320 10........................

AP1 CIRCUIT DIAGRAM 12.................................

AP1 DESCRIPTION OF OPERATION 13......................

AP1 COMPONENT POSITIONS 16...........................

FITTING COMPONENTS ON THE HEAT SINK 17..............

AP2 COMPONENT POSITIONS 18...........................

AP2 DESCRIPTION OF OPERATION 20......................

SOFT STARTING 32........................................

AP5 CIRCUIT DIAGRAM AND COMPONENT POSITIONS 33...

AP6 COMPONENT POSITIONS 34...........................

AP6 DESCRIPTION OF OPERATION 35......................

AP8 COMPONENT POSITIONS 38...........................

AP8 FUNCTION DESCRIPTION 39..........................

AP9 FUNCTION DESCRIPTION 40..........................

AP9, AP10 COMPONENT POSITIONS 47....................

AP10 FUNCTION DESCRIPTION 49.........................

AP11 FUNCTION DESCRIPTION 56.........................

AP11 COMPONENT POSITIONS 57..........................

SETTING UNIT 58..........................................

AP1B, COMPONENT POSITIONS 61........................

AP3B, CIRCUIT DIAGRAM AND COMPONENT POSITIONS 62.

REPLACING THE BATTERY 63..............................

ERROR LOG 64............................................

Error codes 64..............................................

Incorrect--editing codes 72...................................

SERVICE FUNCTIONS 73...................................

LOAD CHARACTERISTICS 91...............................

TECHNICAL DATA 92.......................................

INSTRUCTION MANUAL 93.................................

SAFETY 93...............................................

INTRODUCTION 94........................................

INSTALLATION 95.........................................

OPERATION 99............................................

MAINTENANCE 102.........................................

ORDERING OF SPARE PARTS 102...........................

SPARE PARTS LIST LTS 320 / LTP 450 103....................

ACCESSORIES LTS 320 122.................................

ACCESSORIES LTP 450 125.................................

NOTES 128.................................................

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 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 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 LTP 450 and L TS 320 are designed and tested in accordance with European

standard 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.

INTRODUCTION

LTP 450 and LTS 320 are welding power sources of the rectifier type designed for

mechanised TIG welding.

The LTP 450 and LTS 320 are used together with a setting unit. The design features,

construction and method of operation of the setting unit are described in this manual.

A description of its use, however, is in a separate programming manual.

The programming manuals are available in the following languages:

LTP 450 LTS 320

Language Ordering no. Prog.version Language Ordering no. Prog.version

Swedish

English

Swedish

Danish

English

German

French

Dutch

Spanish

Portuguese

Russian

0456 638 100

0456 638 104

0456 638 170

0456 638 171

0456 638 174

0456 638 175

0456 638 176

0456 638 177

0456 638 178

0456 638 180

0456 638 086

2.10B, 2.11A

2.10B, 2.11B

2.20A, 2.30A

2.20A, 2.21A,

2.30A, 2.31A

2.20A, 2.30A

2.20A, 2.21A,

2.30A, 2.31A

Swedish

English

Swedish

Danish

English

German

French

Dutch

Spanish

Portuguese

Russian

0457 706 100

0457 706 104

0457 706 170

0457 706 171

0457 706 174

0457 706 175

0457 706 176

0457 706 177

0457 706 178

0457 706 180

0457 706 086

2.10B, 2.11A

2.10B, 2.11B

2.20B

2.20B, 2.21B,

2.30B, 2.31B

2.20B, 2.30B

2.20B, 2.21B,

2.30B, 2.31B

Norwegian

Finnish

Italian

0456 638 172

0456 638 173

0456 638 179

2.21A, 2.31A

Norwegian

Finnish

Italian

0457 706 172

0457 706 173

0457 706 179

2.21B, 2.31B

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WARNING

Many parts of the power unit ar e at mains voltage.

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

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 s uitable 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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COMPONENT DESCRIPTION

This component description refers to the diagram for LTP 450 on page 8 and for LTS 320 on

page 10.

AP1 Power board; see the function description on page 13.

AP2 Control circuit board; see the function description on page 20.

AP4 Hall effect sensor, 1 V / 100 A

AP5 Circuit board, suppression (EMC). See circuit diagram on page 33.

AP6 Circuit board for TIG welding; see the function description on page 35.

AP7 HF device, output voltage: 500V peak.

AP8 Interface circuit board for PC; see the function description on page 39.

AP9 Motor circuit board for rotation and wire feed; see the function description

on page 40.

AP10 Motor circuit board for weaving and AVC (Arc Voltage Control).

See the function description on page 49.

Only used in LTP 450.

AP11 Filter circuit board for AVC; see the function description on page 56.

Only used in LTP 450.

C1 -- C2 Capacitors, decoupling.

C3 Start and run capacitor for pump motor M1.

C4 Start and run capacitor for fan EV2.

C6 Capacitor, for speed reduction of cooling fan EV2.

C7 Capacitor, C7 and R3 smooth the no--load voltage.

C8 -- C10 Capacitors, decoupling.

EV1 Fan, 24 V DC. Cools circuit board AP1.

EV2 Fan, 230 V AC.

FU1 MCB, 10 A, protects the 42 V AC supply.

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FU2 Fuse, 2A, slow--blow. Protects fan EV2, pump motor M1 and HF generator

AP7.

HL1 Indicating lamp on the front of the machine. Lights when the main On/Off

switch QF1 is on.

L1 Primary inductor. Filters the mains voltage and improves the power factor.

L2 Secondary inductor. Its inductance exceeds 10 mH at high currents and about

60 mH at low currents.

L3 2+4+4 ferrite ring cores. Reduce transients to/from transformer TM1. See

also V1 below and AP1:3 on page 13.

L4 Ferrite ring core. Suppresses interference in the signal from Hall effect

sensor AP4. The wires from AP4 must be wound four turns around the ring.

M1 Pump motor.

Q1 -- Q2 IGBT modules. See AP1:4 on page 15 and the instructions on page 17.

QF1 Main power supply switch.

QF2 Cooling water pump switch.

R2 Resistor. Discharges capacitor C7 when the no--load voltage is turned off.

R3 Resistor. With C7, it smooths the no--load voltage.

SL1 Flow switch for cooling water. See AP2:11 on page 31.

SL2 Gas flow switch

ST1 Thermal switch: see AP2:9 on page 30, and the fitting instructions

on page 17.

ST2 Thermal switch: controls the fan speed. See AP2:10 on page 30.

ST3 Thermal switch; see AP2:9 on page 30.

TA1 Current transformer, 400:1. Note that it must never be run with open--

circuited secondary. See also AP2:4 on page 24.

TC1 Control power supply transformer.

TM1 Main transformer. See AP1:3 on page 13.

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TV1 HF transformer. The primary winding has one turn, and the secondary

winding has 26 turns. The unloaded secondary winding is about 13 kV peak.

When fitting the transformer it is important that the air gaps in the trans-

former cores are correct. See item 721 in the spare parts list.

V1 Diode modules with secondary diodes. There are five diode modules in the

LTP 450 and four in the LTS 320.

Each module consists of two diodes. The transient voltages produced when

the diodes turn off are suppressed by eight ferrite rings, i.e. four in each

diode leg.

If one diode module is faulty, replace all diode modules.

See page 17 for fitting instructions for V1.

V2 (TY1) Thyristor module. See AP2:8 on page 29 and the instructions on page 17.

V3 LED, yellow. Indicates overtemperature. See AP2:9 on page 30.

VC1 (BR1) Rectifier bridge. See fitting instructions on page 17.

XP Connectors marked XP are male connectors.

XS Connectors marked XS are female connectors.

XS44 Connection for external motor control unit (0457 870 880).

If no external unit is connected a termination resistance must be connected

here. See page 96.

XS45 Connection for external PC. D--sub, 25--pole.

XT Terminal block.

YV1 Solenoid valve for weld gas

YV2 Solenoid valve for start gas

YV3 Solenoid valve for root gas

CONNECTION DIAGRAM LTP 450

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CONNECTION DIAGRAM LTS 320

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AP1 CIRCUIT DIAGRAM

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AP1 DESCRIPTION OF OPERATION

Circuit board AP1 is the mother board in the power section of the power unit. The

components of the power section are mounted on a cast heat sink.

If the IGBT modules, circuit board AP1 and/or circuit board AP2 are replaced, the gate

pulses must be checked and the machine must be soft--started: see pages 26 and 32.

AP1:1 THE MAINS POWER UNIT

The mains voltage is rectified by rectifier VC1. Primary inductor L1

improves the power factor and increases resistance to mains--borne

transients.

Smoothing condensers C12 -- C15 charge up through resistors R3 and R4

when the power is turned on. The two resistors are short--circuited by

thyristor TY1 (V2) about 1.2 seconds after starting. If the thyristor fails to

do this, the two resistors could be burnt out when load was applied to the

machine. Their ratings are 12τ 10 W each and their ordering number is:

0193 775 114.

Resistors R5 and R9 form a potential divider / discharge resistor for

capacitors C12 -- C15.

See page 17 for instructions on fitting VC1 and TY1 (V2).

AP1:2 CAPACITIVE POTENTIAL DIVIDER

Capacitors C1 and C2 form a capacitive potential divider for the centre

point to which the main transformer is connected. Resistors R1 and R2 are

discharge / potential divider resistors.

AP1:3 MAIN TRANSFORMER

The transformer is strip--wound, with four primary turns and 1 + 1

secondary turns.

Its core has an air gap of about 0.13 mm, which is of key importance for

operation of the entire inverter. It must not be reduced or eliminated.

Two ferrite rings, L3, are fitted to the conductors connected to the primary

winding. Their purpose is to attenuate current transients arising from

operation of the IGBT transistors.

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Circuit diagram for circuit board AP1

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AP1:4 IGBT

The switching components in the power section consist of two IGBT

modules, Q1 and Q2, operating at a fixed switching frequency of 20 kHz.

The IGBT modules must never be energised when the gate conductors are

disconnected.

Fitting instructions are given on page 17.

If the IGBT modules have failed, we recommend that the mains rectifier,

VC1, should also be replaced.

AP1:5 TRANSIENT PROTECTION

An RCD filter protects against transients produced by turn--off of the IGBT

modules. It consists of components R18, R19, C10, C11, D1 and D2.

AP1:6 THE GATE CIRCUIT

The IGBT transistors are each driven by their own gate circuits. These

circuits are galvanically isolated from control circuit board AP2 by

transformers TR1 and TR2.

Fuses F1 and F2 protect the gate drive circuits if the power unit should fail.

Instructions for checking the gate pulses can be found on page 26.

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AP1 COMPONENT POSITIONS

The drawing above shows the positions of the contacts on the first and second versions of

circuit board AP1.

On the first version all the contacts on the board are 10 mm high. On later versions contacts

B, C and N are 14 mm high, while contact B has also changed places with contact PE. The

arrows, on the diagram above, are pointing out the contacts.

When fitting this board in machines that have been originally supplied with the first version,

fit the connectors to the following board contacts: XS1 on PE, XS2 on PF and XS4 on PB.

See the circuit diagram on page 12.

Contacts XS1 and XS2 must be secured to the board by means of a cable tie.

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FITTING COMPONENTS ON THE HEAT SINK

Thermally conducting grease

A layer of thermally conducting grease must be applied to the components described below

before they are fitted.

Start by cleaning the heat sink, and then apply a thin, even layer of grease to the contact

surface of the component. The purpose of this grease is to fill any hollows in the surface of

the component and the heat sink: those parts of the component and the heat sink that are in

true metallic contact may have such contact.

Fit the components as described below.

The ordering number for the thermally conducting grease is given on page 110 at item 407 of

the spare parts list. Only the grease recommended by us may be used.

Fitting instructions

Q1, Q2 IGBT MODULES

The IGBT modules are extremely sensitive for ESD. Never touch a

module having an open gate input. Apply appropriate ESD protection

measures when fitting the modules.