Minarcmig evo 200 wire feeder not working.

[Kalleppi3]

Hello. I have a Kemppi MinarcMig Evo 200, and its wire feeder is not working.

I've tested the motor with a power source, and it works just fine. When I press the trigger on the handle, I hear a "click" from the main circuit board, and at the same time, the machine's screen dims slightly. However, the wire feeding motor does not turn.

I've measured that there is no voltage on the wire feeding
motor connectors while pressing the trigger.

After repeatedly pressing the trigger multiple times, the overheat light turns on.
What might be broken? Is there any way to test which component is faulty?

 

[Brad93]

Hello. I have a Kemppi MinarcMig Evo 200, and its wire feeder is not working.

I've tested the motor with a power source, and it works just fine. When I press the trigger on the handle, I hear a "click" from the main circuit board, and at the same time, the machine's screen dims slightly. However, the wire feeding motor does not turn.

I've measured that there is no voltage on the wire feeding
motor connectors while pressing the trigger.

After repeatedly pressing the trigger multiple times, the overheat light turns on.
What might be broken? Is there any way to test which component is faulty?

The clicking is probably a relay or the gas solenoid.

If it is the relay for the wire feeder, you need to trace where it gets its power from. It will be a variable power source i suppose.

 

[Pigeon_Droppings2]

Does sound like a power supply issue....but If you have the case open might be worth pulling the motor and bench testing it too. They're definitely known to fail...sadly its just a cheap generic motor which is annoying given the cost of the machine!

There's a few of us with the Kemppi on the forum who have had motor issues....there's been a few threads on it I think.

 

[Kalleppi3]

The motor has been tested, and it’s working fine.
Is that number 11, transformer giving power for the control card and to the motor?

The screen dims even without the motor connected.

I’ve also heard that control cards have been failing (EVO A001 Control Card SP005448).
How can I test that?

 

[Brad93]

I should think the transformer may be supplying 48VDC etc THEN the board reduces that providing the adjustable voltage for the motor.

 

[Kalleppi3]

Now I measured the voltage from the motor pins. Its giving only 2-4,5 volts. I found an old topic where it says it should measure something like 18volts when the speed is set to a max.

Auxialiry transformer produces 24V like it should.

 

[eddie49]

According to the Kemppi manual:

Weldmet Product Document Viewer

docs.weldmet.co.uk

power for the wirefeed motor comes from an additional secondary winding on the main transformer ( T2, item 18 ), and it should be from 1.8v to 12.6v at Pins X1 /5 and /6. So that is not the auxiliary transformer T002, item 11.

The primary of the main transformer is driven from the DC Link ( 375 volts ) by alternate switching of the two power transistors in the IGBT module. If this is not happening correctly, the additional secondary voltage - for the wirefeed motor - will be low or missing, but also the main secondary voltage - for the arc - will fail. Even without wirefeed, can you still strike a full-power arc?

The "Overheat" light coming on when you try multiple times indicates high temperature, in either the main transformer ( 110 C ) or the IGBT module ( 90 C ), possibly due to a short circuit or loss of correct PWM driver control.

 

[Kalleppi3]

I haven't tried if it strikes an arc. I've only been struggling with the wirefeed motor issue.
I should try to measure the main transformer and the DC link.

I've checked both boards with thermal camera and it does not show that the transformer is overheating. So it might be igbt module that gets too hot.

 

[eddie49]

Yes, measuring the DC bus is a good diagnostic step on an inverter welder.
In a basic machine, after rectification the 230v AC mains will be a similar DC value, then the three large 470uF smoothing capacitors will raise it by 1.414 times, to the peak value of about 325 volts. However this model has a Power Factor Correction circuit, which uses a MOSFET-switched boost converter that raises the voltage to 375v.

Under load the secondary output of an inverter MIG welder will be around 25v, but the OCV can be up to 60v.