ESAB LAW 510 User manual

0740 800 025 9708
LAW 400/500
LAW 410/510
Welding rectifier
Service manual

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LIST OF CONTENTS Page
READ THIS FIRST 3...............................
COMPONENT DESCRIPTION LAW 400/500 4........
CONNECTION DIAGRAM, LAW 400/500 400--415 V
Validformachinenumber 434 ... .... 6.................
CONNECTION DIAGRAM, LAW 400/500 230--500 V
Validformachinenumber 434 ... .... 8.................
CONNECTION DIAGRAM, LAW; 400--415 V
Valid from machine number 512 . . . . . . .10................
CONNECTION DIAGRAM, LAW; 230--500 V
Validfrommachinenumber 512 ... .... 12................
AP1 COMPONENT POSITIONS
Circuit board with part no. 0486 220 880 15..................
AP1 COMPONENT POSITIONS
Circuit board with part no. 0486 291 880 16..................
AP1 COMPONENT POSITIONS
Circuit board with part no. 0486 480 880 (version A) 17.........
FUNCTION DESCRIPTION 18.......................
AP2 SUPPRESSION CIRCUIT BOARD 30.............
TEST ROUTINE 31.................................
FITTING INSTRUCTIONS, THERMAL CUTOUT 33.....
FITTING INSTRUCTIONS, THYRISTOR MODULES 33..
LOAD CHARACTERISTIC 36........................
TECHNICAL DATA 37...............................
PRIMARY CONNECTIONS LAW; 230--500 V 38.......
CONTROL PANEL AND CONNECTIONS 39...........
MAINTENANCE 39.................................
ACCESSORIES 40..................................
DESIGN CHANGES 41..............................
SPARE PARTS LIST LAW 400/500 43................
SPARE PARTS LIST LAW 410/510 55................
Rights reserved to alter specifications without notice

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READ THIS FIRST
This service manual is intended for use by technicians with electrical/electronic training, for
help in connection with fault--tracing and/or repair.
Use the connection diagram as a form of index for the description of operation and the
component description. 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 connection diagram are listed in the component description.
This manual contains details of all design changes that have been made up to and including
August 1997.
The LAW 400/500 and 410/510 are designed and tested in accordance with interna-
tional standard
EN 60 974--1 (IEC 974--1).
On completion of any service or repair, it is the responsibility of the person or
organisation performing the service to ensure that the product still complies with the
above standard.
WARNING
READ AND UNDERSTAND THE INSTRUCTION MANUAL BEFORE INSTALLING OR OPERATING.
ARC WELDING AND CUTTING CAN BE INJURIOUS TO YOURSELF AND OTHERS. TAKE PRECAU-
TIONS WHEN WELDING. ASK FOR YOUR EMPLOYER’S SAFETY PRACTICES WHICH SHOULD BE
BASED ON MANUFACTURERS’ HAZARD DATA.
ELECTRIC SHOCK -- Can kill
SInstall and earth the welding unit in accordance with applicable standards.
SDo not touch live electrical parts or electrodes with bare skin, wet gloves or wet clothing.
SInsulate yourself from earth and the workpiece.
SEnsure your working stance is safe.
FUMES AND GASES -- Can be dangerous to health
SKeep your head out of the fumes.
SUse 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.
SProtect your eyes and body. Use the correct welding screen and filter lens and wear protective
clothing.
SProtect bystanders with suitable screens or curtains.
FIRE HAZARD
SSparks (spatter) can cause fire. Make sure therefore that there are no inflammable materials nearby.
NOISE -- Excessive noise can damage hearing
SProtect your ears. Use ear defenders or other hearing protection.
SWarn bystanders of the risk.
MALFUNCTION -- Call for expert assistance in the event of malfunction.
PROTECT YOURSELF AND OTHERS!

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COMPONENT DESCRIPTION LAW 400/500
The LAW welding rectifiers 500 are 6--pulse thyristor rectifier units intended for
semi--automatic welding. They are available for different mains voltages and with or without
integral cooling units: see the table in the spare parts list on page 55. The component
description below refers to the electrical circuit diagrams on page 6 to 12.
AP1 Circuit board with control electronics: see the function description
on page 18.
AP2 Suppression circuit board, see circuit diagram on page 30.
AP2 has been fitted with effect from machine no. 550 . . . ....
C1 Capacitor, 3 ←F 400 V. Start and run capacitor for fan motor EV1.
C2--C4 Suppression capacitors 0.1 ←F 250 V.
C5 Capacitor, 5 ←F 400 V. Start and run capacitor for pump motor M1. Only
in machines with water cooler.
C6 Capacitor, 6 ←F 400 V. For speed reduction of the cooling fan.
This capacitor has been fitted with effect from machine no. 512 . . . . . .
EV1 Fan
FU1 Circuit breaker, 10 A. Protects the 42 V supply to the wire feed unit.
HL1 Indicating lamp, 42 V, white. Lights when switch QF1 is in the ON
position.
KM2 Contactor 42 V 50 Hz. For speed control of the fan: see ST2 below.
This capacitor has been fitted with effect from machine no. 512 . . . ....
L1 Interphase transformer. When connecting the interphase transformer to
the inductor, it is important that all parts are fitted exactly as shown in
Figure A on page 49.
L2 Inductor. When connecting the inductor, it is important that all parts
are fitted exactly as shown in Figures A, C and D on page 49.
M1 Pump motor, 230 V 50 Hz 0.2 kW. Only in machines with water cooler.
P1 Digital display. Accessory, see the list on page 40. The instrument is
described in the service manual for the MEK 4.
QF1 Main ON/OFF switch.
QF2 Cooling water pump switch. Only on machines with water cooler.
R1 Resistor, 0.43 τ.
RS1 Shunt, 60 mV / 600 A
ST1 Thermal overload cutout. Protects the machine against excessive
temperature. See the function description, item 6, on page 21.
ST2 Thermal switch. Controls the speed of fan motor EV1. The switch closes
when the temperature exceeds 80 _C, energising contactor KM2. This
short--circuits capacitor C6, allowing the fan to run at full speed.
The switch opens when the machine temperature has fallen to 60 _C.
LAW 400/410: ST2 is fitted in the interphase transformer winding, L1.
LAW 500/510: ST2 is fitted in the inductor winding, L2.
Thermal switch ST2 is fitted from machine no. 512 . . . ....

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TC1 Control power supply transformer for LAW with 400--415V mains voltage.
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TC1 Control power supply transformer for LAW with 230--500V mains voltage.
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TM1 Main transformer. Connection instructions for the LAW 400/500 and
LAW 410/510 with 230 -- 500 V mains connection are on page 38.
V1--V6 Thyristor module. See the fault--tracing instructions on page 26 and the
fitting instructions on page 33.
V7 LED, yellow. Lights to indicate operation of the thermal cutouts.
XS1 Connector, 23--pole. For connection to/from the wire feed unit.
XS2--XS4 Main welding current contact, single--pole.
XS5--XS8 Sleeve contacts
XS9 4--pole contact. Only on the LAW 500/510.
XS10--XS15 Sleeve contacts
XT1 9--pole terminal block. Only on machines with 230 -- 500 V mains
connection. See the connection instructions on page 38.
XT2 3--pole terminal block.
Z1--Z6 RC filter.

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CONNECTION DIAGRAM, LAW 400/500 400--415 V
Validformachinenumber 434 ... ....
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1 POWER SUPPLY 8 SHUNT INPUT
2 DISPLAY OUTPUT 9 VOLTAGE REFERENCE
3 MACHINE TYPE / TEST INPUT 10 CRATER FILL
4 CONTROLLED / FIXED FIRING ANGLE 11 START / STOP
5 SYNCHRONISING 12 THYRISTOR CIRCUITS
6 THERMAL OVERLOAD CUTOUT 13 PROCESSOR
7 ARC VOLTAGE
The numerals 1 -- 13 refer to the function description on page 18.

CONNECTION DIAGRAM, LAW 400/500 230--500 V
Validformachinenumber 434 ... ....
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3
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Terminal block XT1 and transformer TC1 are connected for 400 -- 415 V 50 Hz: see the connection instructions on page 38.

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1 POWER SUPPLY 8 SHUNT INPUT
2 DISPLAY OUTPUT 9 VOLTAGE REFERENCE
3 MACHINE TYPE / TEST INPUT 10 CRATER FILL
4 CONTROLLED / FIXED FIRING ANGLE 11 START / STOP
5 SYNCHRONISING 12 THYRISTOR CIRCUITS
6 THERMAL OVERLOAD CUTOUT 13 PROCESSOR
7 ARC VOLTAGE
The numerals 1 -- 13 refer to the function description on page 18.

CONNECTION DIAGRAM, LAW; 400--415 V
Validfrommachinenumber 512 ... ....
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AP2fittedfrommachineno.550 ... ....
Pulse function is added, see page 29.

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1 POWER SUPPLY 9 VOLTAGE REFERENCE
2 DISPLAY OUTPUT 10 CRATER FILL
3 MACHINE TYPE / TEST INPUT 11 START / STOP
4 CONTROLLED / FIXED FIRING ANGLE 12 THYRISTOR CIRCUITS
5 SYNCHRONISING 13 PROCESSOR
6 THERMAL OVERLOAD CUTOUT 14 PRESET
7 ARC VOLTAGE 15 PULSE
8 SHUNT INPUT
The numerals 1 -- 15 refer to the function description on page 18.

CONNECTION DIAGRAM, LAW; 230--500 V
Validfrommachinenumber 512 ... ....
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AP2fittedfrommachineno.550 ... ....
Pulse function is added, see page 29.
Terminal block XT1 and transformer TC1 are connected for 400 -- 415 V 50 Hz: see the connection instructions on page 38.

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1 POWER SUPPLY 9 VOLTAGE REFERENCE
2 DISPLAY OUTPUT 10 CRATER FILL
3 MACHINE TYPE / TEST INPUT 11 START / STOP
4 CONTROLLED / FIXED FIRING ANGLE 12 THYRISTOR CIRCUITS
5 SYNCHRONISING 13 PROCESSOR
6 THERMAL OVERLOAD CUTOUT 14 PRESET
7 ARC VOLTAGE 15 PULSE
8 SHUNT INPUT
The numerals 1 -- 15 refer to the function description on page 18.

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AP1 COMPONENT POSITIONS
Circuit board with part no. 0486 220 880
Points GND1 -- GND6 are connected to the screen casing and to the electronic neutral, 0V

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AP1 COMPONENT POSITIONS
Circuit board with part no. 0486 291 880
Points GND1 -- GND6 are connected to the screen casing and to the electronic neutral, 0V.
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AP1 COMPONENT POSITIONS
Circuit board with part no. 0486 480 880 (version A)

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FUNCTION DESCRIPTION
Sections 1 -- 15 below refer to the diagrams on page 6 to 12.
The circuit board is screened by a screened enclosure that is connected to 0 V on the circuit
board.
The component position drawings on page 15 to 17 also shows components that are not fitted
to the circuit board. These components are not used in the LAW power units.
1POWER SUPPLY, CIRCUIT BOARD AP1
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The power supplies from transformer TC1 to the circuit board are prepared for
fitting PTC resistors, but are now fitted with links BY1 -- BY4.
DC power supplies
The power supply supplies the following DC voltages :
+25 VC, ¦15 V, +15 VB, +5 V and +12 V.
+5V
Internal power supply on the circuit board. Voltage regulator VR2 is
adjustable: the voltage is adjusted to 5.00 ¦0.01 V when the board is
manufactured.

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+12V
Power supply to the display board and for loss of voltage detection.
See also Items 2 and 13 below.
+15VB
Power supply to circuits that are galvanically or high-- resistance separated from
other electronics on the circuit board.
+/--15V
Internal power supply for the circuit board.
+25VC
Internal power supply for the circuit board, protected by a PTC resistor, R150.
The resistance value of this resistor increases in the event of current overload.
2DISPLAY OUTPUT
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Outputs G1 -- G3 are used for serial data transfer of the welding current and arc
voltage to a digital display instrument, which may be fitted either in the power unit
or in the wire feed unit. The instrument is described in the service manuals for the
wire feeders MEK 4/4S/4SP.
Outputs G4 and G5 supply +12 V to the instrument. This supply is protected by
PTC resistors R155 and R154. The resistors protect the circuit board against short
circuits to arc voltage or against other voltages occurring in the control cable to the
wire feed unit.

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3MACHINETYPE/TESTINPUT
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J3 and J4 must be linked in the LAW 500/510: if the link is removed, the machine
will operate as an LAW 400. But never link J3 and J4 in an LAW 400/410.
Test input
Use the test inputs to test the performance of several input and output signals on the
circuit board. See the description on page 31.
4FIXED / CONTROLLED FIRING ANGLE
When K2 and K3 are linked, the machine operates with a fixed thyristor firing
angle. When K1 and K2 are linked, the machine operates with a controlled
(variable) thyristor firing angle.
A fixed thyristor firing angle means that the thyristor output is affected only by the
setting of the voltage control potentiometer.
A controlled (variable) thyristor firing angle means that the thyristor output is also
affected by the actual value of the arc voltage (arc voltage control). This means that
the machine compensates for variations in mains supply voltage.
It is only possible to change between controlled and fixed thyristor firing angle
when the machine is switched off.
Circuit board 0486 220 880 must be used only with fixed thyristor firing angle.
Circuit boards 0486 291 880 and 0486 480 880 are to be used with controlled
thyristor firing angle.
LAWmachineswithserialnumbersof 512 ... .... andabove are supplied with
controlled thyristor firing angle.
For machines with circuit board 0486 220 880 there is an exchange circuit board
with controlled thyristor firing angle.
The ordering number for the exchange board is: E486 220 882.