Service manual

Ver. 1.1

Contents

General………..…………………………………………..3
Operating panel…………………………………………..3
Technical data…………………………………………… 4
Operating principle………………………………………4
Main circuit ………………………………...…………….5
Main circuit diagram.……………………………………6
Control card A001 connectors X3 and X5……………...6
Block diagram…………………………………………….7
Troubleshooting…………………………………………..8
Operational tests / measurings…………………..............9

DC-link charging………………………………..10
IGBT gate pulse...…………………………….....11
Main transformer T001 primary voltage......……12
Main transformer T001 secondary voltage 1/2....13
Main transformer T001 secondary voltage 2/2…14
Secondary voltage before choke………………...15
Auxiliary voltages…………..…………………...16
Plate thickness adj. set value………….................17
Voltage fine tune pot. set value………….............18
Wire feed power supply………………….............8
Wire feed motor max. voltage.................……….18

Main circuit card Z001 layout…………………………...19
Main circuit card connectors and measuring points…...20
Control card A001 layout………………………………. 21
Control card A002 layout………………………………. 21
Structure…………………………………………………. 22
Power semiconductors testing and replacing….………. 23

General

MinarcMig

TM

Adaptive 150-power source has adaptive control; the welder uses one knob to select

the weled plate thickness and the power source automatically finds the optimal welding
parameters. Arc dynamics is optimized according to the adjusted plate thickness, filler wire and
shielding gas.

Plate thickness selection

Arc length adjustment

Long arc

Short arc

Normal setting

Main switch signal lamp

Overheat protection signal lamp

Current

Voltage

Adaptive

power

increase

1. The plate thickness is selected

2. The filler wire is detected by the short circuits, and
according to this information the arc properties are
automatically optimized.

Power adjustment by one knob

Short circuit

2,0...3,0 ms

Operating panel

3

Technical data

Supply voltage, 1~ 50/60 Hz

230 V ± 15%

Loadability

35% ED

150 A / 21,5 V (6,9 kVA)

60% ED

120 A / 20,0 V (5,3 kVA)

100% ED

100 A / 19,0 V (4,2 kVA)

Supply cable / fuses

2,5 mm² S - 3,3 m / 16 A

Adjustment range

20 A / 13,5 V…150 A / 22,0 V

Wire feed speed adjustment range

1,0…11,0 m/min

OCV

22…31 V

Efficiency

0,8 (150 A / 21,5 V)

Power factor

0,58 (150 A / 21,5 V)

Filler wires

Fe, Ss

0,6…1,0 mm

Flux core wire

0,8…1,0 mm

Al

-

Degree of protection

IP 23C

Dimensions

Length

400 mm

Width

180 mm

Height

340 mm

Weight (including gun and cables)

9,4 kg

Operating principle

MinarcMig Adaptive 150-power sources are ”dual-Forward”-inverters, controlled by PWM
principle. Switching components are IGBT transistors. Operating frequency of the power source is
approximately 80 kHz. Below is a principle picture of a ”dual-forward”-inverter:

VDC

t

75

13µs

approx. + 320 V

V1

V2

The power is adjusted by altering the IGBT-transistor (V1 and V2) timings (PWM). When IGBT-
transistors are in non-conductive state the current is reduced and passes through diode V4.

V3

V4

4

Main circuit

+ t

+ t

X5

X3

X1

R1

7

R2

0

L2

C1

0

C9

C1

1

L1

R19

R18

C1

3

V2

5

V

26

V9

C1

, C

2,

C3

V

10,

V

11,

V

12,

V

13

V

1, V

2,

V

3,

V

4

V5,

V6,

V

7,

V

8

T0

01

T1

K1

X12

X13

X18

X17

C1

2

X2/5

X2/4

V1

9

R1

3

U

R1

1

R1

2

C4

R2

R1

V

14,

V

15,

V

16,

V

17

X2/1

X2/9

X2/10

X2/2

X2/3

V1

8

Primary circuit.

R2

1

U

R1

4

C1

4

R1

6

C1

5

X4

V23

V24

V21

V22

V20

X14

X2

/8

X9

X16

ML2

MA2

ML1

MA1

X19

R1

5

X2

0

Secondary circuit.

5

Main circuit diagram

Solenoid valve

Wire feed motor

Gun start switch

Fan

Operating panel

Control card

Main circuit card

Main transformer

PTC

Secondary choke

EMI-choke

Main switch

Aux. transformer

X5/1

Voltage adjustment potentiometer R002 (+)

X5/2

Voltage adjustment potentiometer R002 (-)

X5/3

Voltage adjustment potentiometer R002 glide

X5/4

Overheat signal lamp H001 (-)

X5/5

Overheat signal lamp H001 (+)

X5/6

On-signal lamp H002 (-)

X5/7

On-signal lamp H002 (+)

X5/8

Plate thickness potentiometer R001 glide

X5/9

Plate thickness potentiometer R001 (-)

X5/10

Plate thickness potentiometer R001 (+)

Control card A001 connector X5

X3/1

GND

X3/2

GND

X3/3

Opto (net voltage watch)

X3/4

+ 24 V (DC-link charging relay K1)

X3/5

DC-link charging relay K1 control

X3/6

IGBT gate pulse

X3/7

-

X3/8

Output voltage (U

2

)

X3/9

Current transformer

X3/10

Current transformer

Control card A001 connector X3

X3/11

Temperature watch PTC

X3/12

-

X3/13

Temperature watch PTC

X3/14

-

X3/15

-

X3/16

-

6

Block diagram

Control card A001

Auxiliary voltages development

Undervoltage watch

Overvoltage watch

Temperature watch

Wire feed control and power stage

Solenoid valve control

Power stage control

Main circuit diagram Z001

Overvoltage protection

DC-link charging

EMI-filter

Primary rectifier

Energy reserve

”Dual-forward”-inverter

Secondary rectifying

16

Operating panel A002

Plate thickness adj. potentiometer

Voltage fine adjustment potentiometer

Overheat signal lamp

Main switch signal lamp

10

7

Troubleshooting

The machine may be repaired only by an authorized and licensed technician or workshop!

First do a visual check to find the possible loose connectors, broken wires or signs of
overheating.

Also note the condition of the consumable parts of the wire feeder and welding gun, because
most problems in MIG/MAG-welding are related to wire feeding.

PROBLEM

POSSIBLE CAUSE

REMEDY

The power doesn´t start, panel´s
signal lamp H002 is not lighted

Aux. transformer T002

Check aux. transformer T002
secondary voltage between
connectors X1/7-X1/8 (approx. 23
Vac)

Control card A001

If aux. transformer secondary
voltage is approx. 23 Vac, then
replace control card A001

The net fuses blow in machine
start

Faulty primary circuit
semiconductor

Check the primary side
semiconductors. See the IGBT
testing on page 23

Auxiliary transformer T002

Check auxiliary transformer T002
condition

Welding power doesn´t follow
the plate thickness potentiometer
R001

A faulty plate thickness
potentiometer R001

Check the condition of the plate
thickness potentiometer (R001 = 10
kΩ)

A faulty control card A001

Replace control card A001

The power source doesn´t deliver
full power

A faulty primary rectifier V9

Check the primary rectifier
condition and solderings

A faulty smoothing capacitor

Check the smoothing capacitors
C1…C3 and solderings

A faulty secondary rectifier

Check the secondary diodes and
solderings

A faulty control card A001

Replace control card A001

Wire feeding is sticky and the arc
is interrupted

Control card A001 resistor R39

Check control card resistor R39
condition and replace as necessary
(R39 = 47

Ω / 1 W)

Troubleshooting diagram

8

Operational tests / measurings

B

A

C

D

E

F

Measuring point A. DC-link charging
Measuring point B. IGBT gate pulse
Measuring point C. Main transformer T001 primary voltage
Measuring point D. Main transformer T001 other secondary coil voltage
Measuring point E. Main transformer T001 Voltage of both secondary coils
Measuring point F. Secondary voltage before choke

9

+ t

+ t

X5

X3

X1

R1

7

R2

0

L2

C1

0

C9

C1

1

L1

R19

R18

C1

3

V25

V

26

V9

C1

, C

2,

C3

V10

, V11

, V12

, V1

3

V1,

V2,

V3

, V4

V5,

V

6,

V7

, V8

T0

01

T1

K1

X12

X13

X18

X17

C1

2

X2/5

X2/4

V19

R1

3

U

R1

1

R1

2

C4

R2

R1

V14

, V15

, V16

, V1

7

X2/1

X2/9

X2/10

X2/2

X2/3

V18

A

Measuring point A. DC-link charging

DC-link smoothing capacitors C1, C2 and C3 are charged through PTC-resistors R18 and R19
(25

Ω), which reduces thr switching transient conducting to the net. DC-link charging takes

approximately 0,7 s.

Primary

Secondary

10

A

B

B

With setting: plate thickness adjustment = maximum, voltage fine tune = middle point
With load: LVR 600 = resistance 200 as load (100 A / 15 V)

Measuring point B. IGBT gate pulse

11

C

C

With setting: plate thickness adjustment = maximum, voltage fine tune = middle point
With load: LVR 600 = resistance 200 as load (100 A / 15 V)

Measuring point C. Main transformer T001 primary voltage

12

D

D

With setting: plate thickness adjustment = maximum, voltage fine tune = middle point
With load: LVR 600 = resistance 200 as load (100 A / 15 V)

Measuring point D. Main transformer T001 other secondary coil voltage

13

E

E

With setting: plate thickness adjustment = maximum, voltage fine tune = middle point
With load: LVR 600 = resistance 200 as load (100 A / 15 V)

Measuring point E. Main transformer T001 voltage of both secondary coils

14

F

F

With setting: plate thickness adjustment = maximum, voltage fine tune = middle point
With load: LVR 600 = resistance 200 as load (100 A / 15 V)

Measuring point F. Secondary voltage before choke

15

G

G

Measuring point G. Auxiliary transformer T002 secondary voltage

Auxiliary voltages are formed from auxiliary transformer T002 secondary voltage: + 30 V for
fan M002, DC-link charging relay K1 and solenoid valve Y001, regulated + 24 V for power
stage PWM controller D1 and gate buffer and +15 V for other electronics.

G

16

Auxiliary voltages

217

I

A

O

M

H0

02

X1/7

X1/8

V1

4

V1

3

V1

6

V1

5

C6

C1

5

M0

02

R9

3

R12

R11

C5

+ 30 V

+ 24 V

X5

/7

X5

/6

X2

/1

X2

/2

T

002

+ 15 V

C1

0

V2

3

N1

R1

14

Measuring point H. Plate thickness set to
min - max, (A001 X5/8-X3/1)

H

I

Measuring point I. Voltage adjustment
short arc - long arc, (A001 X5/3-X3/1)

H

I

17

Plate thickness and voltage fine tune set values

J

J

Measuring point J. Wire feed power
supply (A001 X1/5-X3/1)

K

Measuring point K. Wire feed motor´s
average voltage max. (A001 X1/5-X1/6)

K

18

Wire feed power supply and wire feed motor voltage

Main transformer T001

IGBTs, gate resistors
and return-diodes

Smoothing capacitors

Primary rectifier

EMI-filter

DC-link charging
resistors and -
relay

Secondary rectifier

Current transformer T1

Pulse transformer T2

Main circuit card Z001 layout

19

Main circuit card Z001 connectors and measuring points

X4

X16

X19

X13

MA1

MA2

ML1

ML2

X9

X14

X17

X18

X12

X5

X1

X2

X21

X22

X20

X3

A

B

C

D

E

F

Measuringpoint A. DC-link charging
Measuringpoint B. IGBT gate pulse
Measuringpoint C. Main transformer T001 primary voltage
Measuringpoint D. Main transformer T001voltage of the other secondary coil
Measuringpoint E. Main transformer T001 voltage of both secondary coils
Measuringpoint F. Secondary voltage before choke

20

X5

X1

X2

R10
Wf-max.

X3

X4

Control card A001 layout

R001
Plate thickness

R002
Voltage

H001

H002

Control card A002 layout

X1

21

Solenoid valve

Y001

Main switch

S001

Choke

LZ101

Fan

M002

Main circuit card

Z001

Control card
A002

Wire feed motor
M001

Secondary choke
L001

Control card
A001

Aux. transformer
T002

Structure

22

Discrete-IGBTs can be tested by IGBT-tester.

When replacing damaged IGBT-transistors, they must
allways be changed as a set including the gate
resistors!!

The tightening torque of the discrete-IGBTs and
secondary diodes to the heatsink is 0,6…1,2 Nm.

G

C

E

IG

B

T

-T

E

S

TE

R

T

R

1

T

R

2

C

O

N

T

R

O

L

O

FF

O

N

B2

/6

C2

E1/

1

E

2

/2

C1/3

B1/4

Power semiconductor testing and replacing

Notes

23