Troubleshooting guideVer 1.0

Contents

Technical data……………………………………….

Operation principal…………………………………..

Main circuit………………………………………….

Troubleshooting chart……………………….…...….

Main circuit diagrams……………………………….

Functional tests/measurings…………...............…….

Measuring points…………...……...…..

Main transformer T001 prim. Voltage...

Main transformer T001 sec. Voltage......

Voltage after secondary rectifier…........

IGBT gate pulse…………………..…...

Control card A001 connectors…………………...….

Control card A001 layout…………………....……...

IGBT-transistor testing…….............………………..

Secondary diodes testing…………….……………...

Service infos………………………….....…………..

Notes………………………………….............……..

3

4

4

5

6

7

7, 8

8, 9

9, 10

10, 11

11-13

14

15, 16

17

17

18-20

21

Minarc 140 Minarc 110Supply voltage, 1~50/60 Hz 220 V –10%…240 V +6% 220 V –10%…240 V +6%Loadability 35%ED 140 A (7,5 kVA)

50%ED 110 A (5,5 kVA)100%ED 100 A (5,1 kVA) 80 A (3,9 kVA)

Connection cable / fuses 2.5 mm² S / 3,3 m 16 A 1.5 mm² S / 2.0 m 13 AWelding current range MMA 10 A / 20.5 V…140 A /

25.6 V10 A / 20.5 V…140 A /25.6 V

Stick diameter ø 1.5…3.25 mm ø 1.5…2.5 mmWelding current adjustment Portaaton PortaatonOCV + 105 V * + 105 V *Idling power < 10W < 10WEfficiency 0.8 0.8Power factor 0.60 (140 A / 25.5 V) 0.60 (110 A / 24.4 V)Temperature class B (130°C) / H (180°C) B (130°C) / H (180°C)Operating temperature -20…+40°C -20…+40°CStock temperature -40…+60°C -40…+60°CCasing class IP 23C IP 23CNorms IEC 974-1 IEC 974-1

EN 50199 EN 50199Measures Length 305 mm 305 mm

Width 123 mm 123 mmHeight 250 mm 250 mm

Weight 4.2 kg (4.8 kg) 4.2 kg (4.6 kg)

* From serial number 1085088/M onwards the OCV is approx. + 85 V

Technical data

3

Operating principal

VDC

t

105

13µs

Max

. 0,5

n. + 320 V

1/3

V1

V2

When IGBT-transistors V1 and V2 are not conductive, no power is transferred. The power is adjusted by changing the IGBT-transistors conductive timings (PWM).

Main circuit

+ t + t

X3

X1

X2

R69

R70

L2

C28

C22

C5

L1

R59 R54

C43

V26

V23

V9

C1,

C2,

C3 V

5, V

32

V1,

V31

V2,

V3,

V4

V6,

V7,

V8

T001

T2

K1

T001

U

R64 U

V29, V30

C39R65

R66

C38

V27

, V28

R63

X18

X17

L001

L002

X003

X004

X16

X3

X2

Z001

Minarc power sources are ”dual-Forward”-inverter power sources, controlled by PWM method. The switching components are IGBT-transistors. Inverter operating frequency is approx. 80 kHz. Below is a picture of the ”dual-forward”-inverter operating principal:

4

General

DISTURBANCE POSSIBLE CAUSE REMEDYPower source not starting; OCV ~0 V; Yellow overheat led H001blinking.

Fan M001 Disconnect the fan connector X15and start the power source. If thepower source starts and the OCVrises, then replace the fan.

Secondary choke L001 in shortcircuit with minus pole X004.

Add an insulator ring to the minuspole X004. See service info 02 /2002, page 18.

Secondary rectifier diodes inshort circuit.

Check the secondary rectifierdiodes condition and replace ifneeded. See secondary diodestesting, page 17.

Faulty primary circuit powersemiconductor.

Check primary side powersemiconductors. If the voltage overPTC-resistor R59 is over 230 Vac,there is a short circuit in theprimary side. Replace the faultypower semiconductor. See IGBT-transistor testing, page 17.

Diode V24 is in short circuit oncontrol card A001.

Check the diode, and replace ifneeded.

Faulty control card A001. Replace control card A001The power source starts and theOCV rises to 85 V, after whichthe power source shuts down;The power source can´t beloaded.

Relay K1 Check the relay operation. See theservice info 03 / 2002, page 19.

Welding current can´t be adjustedby the potentiometer R001.

Faulty potentiometer R001. Check the potentiometer condition(R001 = 10 kΩ)

Faulty control card A001. Replace the control card A001.

5

Machine repairs may only be done by a company or repairman authorized to do the work!

First check visually if there are any signs of damage in the machine, for example loose wires,breaks or signs of overheating.

Troubleshooting chart

Main circuit diagrams

Main circuit diagram from serial number 1085088/M onwards (OCV approx. + 85 V)

Main circuit diagram, before serial number 1085088/M (OCV approx. + 105 V)

6

Functional tests / measurings

1

2

3

Measuring point 1. Main transformer T001 primary voltageMeasuring point 2. Main transformer T001 secondary voltageMeasuring point 3. Voltage after the secondary rectifier

7

Measuring points on the control card A001

Main tranformer T001 primary voltage, 10 A

Measuring point 1. Main tranformer T001 primary voltage

1

2 3

4

8

Päämuuntajan T001 ensiöjännite, 140 A

Measuring point 2. Main transformer T001 secondary voltage

Main tranformer T001 secondary voltage, 10 A

Measuring point 1. Main transformer T001 primary voltage

9

Main transfomer T001 secondary voltage, 140 A

Measuring point 3. Voltage after secondary rectifier

Voltage after the secondary rectifier, 10 A

Measuring point 2. Main transformer T001 secondary voltage

10

Measuring point 4. IGBT gate pulse

IGBT gate pulse, 10 A

Measuring point 3. Voltage after the secondary rectifier

Voltage after the secondary rectifier, 140 A

11

IGBT gate pulse, 140 A

IGBT gate pulse, 60 A

Measuring point 4. IGBT gate pulse

12

IGBT gate pulse with open circuit (OCV approx. + 105 V)

Measuring point 4. IGBT gate pulse

IGBT gate pulse with open circuit (OCV approx. + 85 V)

13

Control card A001 connectors X15

X19

X3X2X1

X16

X18

X17

X004

X4X5X6X7

X8

X24 X23 X10

X11

X14

X13

X12

X9

X20

Connector SignalX1, X2 Net voltage 230 VacX3 Protective earthX4, X6, X8 Current adjustment

potentiometer R001X5, X7 MMA/TIG-selection switch

S002X9, X11 Main transformer T001

auxiliary coilX10, X12 Main transformer T001 PTC

RT101X13, X14 Primary profile PTC RG201X15 FanX16, X17 Main transformer T001

secondaryX18 Secondary choke L001X19, X20 Main transformer T001 primaryX23 PWM-circuit N1 VFB, pin 2X24 + 5 V

14

Control card A001 layout

X4

The older version control card A001, 4292730

The new control card A001, 4298870 15

Control card A001 layout

EMI-filterIntermediate circuit charging(Rele 9766230)

Rectifier unit(9750191)

Smoo

thin

g ca

paci

tors

(975

5615

)IGBTs and opposite diodes

(IGBT-set 4297750)

Secondary rectifier unit(4297740)

LED(9775757)

Varistors(95 V 9753590, 175 V 9753588)

16

IGBT-transistors testing

G C E

IGBT-T

ESTE

R

TR 1

TR 2

CO

NTR

OL

OFF O

N

B2/6

C2E1/1

E2/2

C1/3

B1/4

Discrete-IGBT (50 A, 600 V) can be tested with the IGBT-tester.

When replacing damaged IGBT-transistors the whole setmust be always replaced. The gate resistors (10Ω) must be checkedand replaced if necessary. Spare part IGBT set 4297750.

Discrete-IGBT tightening torque to the heatsink is 0,6…1,2 Nm!

Testing the secondary diodes

When testing the secondary diodes the other coil end of the maintransformer T001 has to be disconnected. The main transfomercoils and connectors may not be bent!

If the secondary diodes are in short circuit, the power sourcedoesn´t start.

Secondary rectifier unit 4297740.

The tightening torque for the secondary diodes is 0,6…1,2 Nm!

Solderings should be done carefully, because of high currents,approx. 30 A/ leg!

60 A, 200 V types APU02 or 214160 A, 400 V types APU04 or 2154

17

Service infos02 / 2002 Minus pole insulator

Power sourcesMinarc 110 & 140

ModificationAn insulator 9771963 is added to the minus-pole. See the attached picture.

Reason for midificationSecondary choke may cause a short circuit between plus- and minus-poles. This is prevented by installing the inslulator 9771963 to the minus-pole.

ProductionThe modification is valid from serial number 1023532/K onwards.

Power sources with serial number before 1027716/KThe modification can be carried out during service or repair work.

18

Service infos 03 / 2002 IGBT gate resistors and intermediate circuit charging relay

Power sourcesMinarc 110 & 140

ModificationIGBT gate resistors (10 ohm.) have been added to the spare part set (4297750).

Reason for modificationIf the IGBTs are damaged, also the gate resistors (R2, R4, R5, R6, R7 and R8) may be damaged.For example if one resistor has been destroyed, then the IGBT doesn´t get gate control and thiscauses overload to the other IGBTs. When IGBTs are replaced then the gate resistors must bechecked too. See the attached picture.

DC-link(Intermediate circuit) charging relay K1 (9766230)If fan rotating speed drops after the machine starts and the OCV is max. 85 volts, then mostlikely the DC-link charging relay is not working. In some cases there has been lacquer insidethe relay and it is stuck. Relay control voltage is approx. +28 volts.

19

Service infos20 / 2002 A new control cardi A001 and filter card Z001

Power sourcesMinarc 110 and 140

ModificationControl card A001 and filter card Z001 have been replaced with new versions. The new sparepart codes are as follows:

Power source Control card A001 Filter card Z001MINARC 140 4298870 4298600MINARC 110 4301880 4298600

Reason for modificationThe OCV is lowered to 85 Volts.

CompatibilityThe new and old card versions are compatible. NOTE !! Only a combination of a new controlcard A001 (4298870, 4301880) and a new filter card Z001 (4298600) lowers the OCV to ~ 85Volts. See the chart below:

Power source Control card A001 Filter card Z001 OCVMINARC 140 4298870 (new version) 4298600 (new version) ~ 85 VDCMINARC 140 4298870 (new version) 4294620 (old version) ~ 105 VDCMINARC 140 4292730 (old version) 4298600 (new version) ~ 105 VDCMINARC 110 4301880 (new version) 4298600 (new version) ~ 85 VDCMINARC 110 4301880 (new version) 4294620 (old version) ~ 105 VDCMINARC 110 4294440 (old version) 4298600 (new version) ~ 105 VDC

ProductionThe modification is valid in production onwards from the following serial number:MINARC 110/140 1085088/M

StockOnly cards of the new type are available.

Power sources manufactured befre serial number 1085088/MOCV lowering is not warranty covered.

20

Notes

21