Arc Captain cut 55

[Fishaholic001]

A friend of mine bought this machine 2 months ago and he didn’t follow the proper instructions and when he moved from 110 to 220 it blew both capacitors on the board. He got mad and brought it to work and gave it to me. I took the board out of it and ran my meter at over it. And can’t find any burnt spots or problems with the board other than the two capacitors that blew out is it possible for me to change those myself and save the machine I can do it. I just wanna know if anyone here has done it.

 

[Erie Fred]

Some pix would help.

 

[Fishaholic001]

What would you like pics of? It’s a arc captain cut 55 and this is the capacitor x2
I don’t have the machine with me. I’m at work till 5:30.

 

[Erie Fred]

What would you like pics of? It’s a arc captain cut 55 and this is the capacitor x2
I don’t have the machine with me. I’m at work till 5:30.

The machine.

 

[Fishaholic001]

Machine just happens to be 20 miles away from my work at home. I don’t have pictures of the machine itself. It’s less than a month old and still in the box. He switched from 110 to 220 to fast and didn’t follow the manual and pow blew both side by side capacitors. Under the magnifying lens, the rest of the board was perfect. It just melted the two slots where the capacitor slip in, but unfortunately I won’t be able to get to that machine until about 6 o’clock this evening when I get home from work and I’ll take a series of pictures of it.

 

[Erie Fred]

Machine just happens to be 20 miles away from my work at home. I don’t have pictures of the machine itself. It’s less than a month old and still in the box. He switched from 110 to 220 to fast and didn’t follow the manual and pow blew both side by side capacitors. Under the magnifying lens, the rest of the board was perfect. It just melted the two slots where the capacitor slip in, but unfortunately I won’t be able to get to that machine until about 6 o’clock this evening when I get home from work and I’ll take a series of pictures of it.

Fine with me.
Not going to try and help you anymore.

 

[Fishaholic001]

Fine with me.
Not going to try and help you anymore.

I suppose you wanted me to leave work drive 20 miles for a picture. I just got home and I’m taking pictures now. If you want to help cool if not that’s fine too.

 

[Fishaholic001]

I suppose you wanted me to leave work drive 20 miles for a picture. I just got home and I’m taking pictures now. If you want to help cool if not that’s fine too.

 

[eddie49]

Hi and welcome to the Forum.

A capacitor rated at 200v could not be used on a 220v supply, so these two must have been connected in series, giving a 400v rating and an effective capacity of 1100uF
It is rare for the capacitors in the inverter power section of a welder or plasma cutter to blow, normally it is the power semiconductors that fail. Perhaps they were just of low quality or had a manufacturing defect.

Does the machine data plate or manual state that it is 220v capable? Does the swap of input power from 110 to 220 involve switches, jumpers, or a power cable adapter? If it ran OK on 110 and was also certified for 220. it should have just worked.

You should find that there is a bridge rectifier more-or-less directly across the mains input. There will be a relay-controlled soft start circuit, and maybe a mains noise filter too. Without the capacitors, the output of the rectifier will be about the same as the mains input, but DC.
Adding the capacitors - i.e. new replacements - will raise that to near the peak value, which is 1.4 times higher. This 154 or 308 volts DC then supplies the inverter power switching circuit.

I would suggest that you first power-up the machine on 110v before replacing the capacitors, and check the rectifier output. The cutter will not work, but any other faults later in the circuit may be revealed. An old trick is to connect the power in series with a 110 volt 100 or 200 Watt filament light bulb. If there is a short, the lamp will light brightly. If that checks out OK, add new capacitors and test the machine. Then try stepping up to a 220v source.

 

[Fishaholic001]

Hi and welcome to the Forum.

A capacitor rated at 200v could not be used on a 220v supply, so these two must have been connected in series, giving a 400v rating and an effective capacity of 1100uF
It is rare for the capacitors in the inverter power section of a welder or plasma cutter to blow, normally it is the power semiconductors that fail. Perhaps they were just of low quality or had a manufacturing defect.

Does the machine data plate or manual state that it is 220v capable? Does the swap of input power from 110 to 220 involve switches, jumpers, or a power cable adapter? If it ran OK on 110 and was also certified for 220. it should have just worked.

You should find that there is a bridge rectifier more-or-less directly across the mains input. There will be a relay-controlled soft start circuit, and maybe a mains noise filter too. Without the capacitors, the output of the rectifier will be about the same as the mains input, but DC.
Adding the capacitors - i.e. new replacements - will raise that to near the peak value, which is 1.4 times higher. This 154 or 308 volts DC then supplies the inverter power switching circuit.

I would suggest that you first power-up the machine on 110v before replacing the capacitors, and check the rectifier output. The cutter will not work, but any other faults later in the circuit may be revealed. An old trick is to connect the power in series with a 110 volt 100 or 200 Watt filament light bulb. If there is a short, the lamp will light brightly. If that checks out OK, add new capacitors and test the machine. Then try stepping up to a 220v source.

Thank you for the information and advice. Yes it is a dual voltage system. It was just given to me on Wednesday. I honestly haven’t read the manual yet but my friend that had it which it’s less than a month old and this was the 3rd time using it said that there was some procedure that he was supposed to follow when switching voltages but the 120 wasn’t cutting clean So he unplugged it and plugged it in to the 220 and he said it went off like a bomb. He got mad put it back in the box and brought it to work and gave it to me

 

[trigger3]

I suppose you wanted me to leave work drive 20 miles for a picture. I just got home and I’m taking pictures now. If you want to help cool if not that’s fine too.

that guy hasnt a clue. you posted the photos he wanted but he disappeared. he did basically the same thing on one of my threads. blabbed a bunch of nonsense and disappeared

 

[Fishaholic001]

that guy hasnt a clue. you posted the photos he wanted but he disappeared. he did basically the same thing on one of my threads. blabbed a bunch of nonsense and disappeared

I figured as much. Acted up set because I wouldn’t run 20 miles home and give him pictures. That’s why I figured I would overload him with pictures and short circuit his brain

 

[Muzzer]

There's a reasonable chance it might still work if you replace the blown cap(s). If it was switched to 120V operation but connected to 240V, it's not a great surprise that it vented the caps in this way. However, I assume it didn't get as far as actually activating the arc as it would still have been initialising, in which case that part of the machine may well still be functional.

When being tested for UL, CSA, CE etc certification, this kind of explosive venting isn't considered acceptable, so normally there would be some sort of voltage limiting device across the bus caps, such as VDRs or gas discharge devices which would cause the input fuse to blow first. The Arc Captain products look pretty well designed internally (I have their MIG and TIG machines, which I've done non destructive teardowns on), so I'm a bit disappointed (or is that simply naive?) to see this kind of failure.

 

[voipio]

There are a couple of other 200V rated capacitors showing in the images. I would suggest replacing those, too. Although they didn't go bang, their internals might have started cooking.

 

[TryingToWeld]

If it was switched to 120V operation but connected to 240V, it's not a great surprise that it vented the caps in this way.

But the American system is split phase, effectively 240V sockets are fed from a centre tapped transformer. So, switching from 120 to 240V or vice versa, is acheived simply by connecting or disconnecting one phase. I don't understand why that would blow the capacitors? Are they on the same phase, or are there two more identical ones for the other phase?

In any case I would also check the bridge rectifiers, they can be made up of indiviual diodes (normally 4, but could be 2) or 4 pin encapsulated devices. You can do that with a basic multimeter on the resistance range, look for short ccts. Or, if your meter has a diode test range, a good diode has a reverse voltage of 0.7V.

Also, BEFORE you do anything make sure the big capacitors are fully discharged, they can hold their charge for hours. Check the voltage across them, and if neccessary discharge them with a nice big wirewound resistor.

 

[BrokenBiker]

Fine with me.
Not going to try and help you anymore.

from what i can see you hadnt started to help in the first place...your insolance is becoming more apparent as the weeks go by

 

[TryingToWeld]

So he unplugged it and plugged it in to the 220

I'm in the UK so pardon my ignorance, but I assume a 220V and 110V plug are physically different, and not interchangeable? In which case he would have changed the plug? So I would check it's wired correctly.

 

[BrokenBiker]

I'm in the UK so pardon my ignorance, but I assume a 220V and 110V plug are physically different, and not interchangeable? In which case he would have changed the plug? So I would check it's wired correctly.

im not entirely sure thats true...im in the uk too, but i think that all single phase in america is the same plug. im sure ive seen welder review videos where they have tested 110 and 220 on the same machine and just swapped to a different socket. i may be wrong though but realistically, the machine should either be able to sense the voltage or have a switch to change over anyway

 

[eddie49]

I'm in the UK so pardon my ignorance, but I assume a 220V and 110V plug are physically different, and not interchangeable? In which case he would have changed the plug? So I would check it's wired correctly.

We are still waiting for answers:

Does the machine data plate or manual state that it is 220v capable? Does the swap of input power from 110 to 220 involve switches, jumpers, or a power cable adapter?

A machine that is or can be made to be 220-capable is sometimes shipped with a short power cable adapter to allow connection to a 220 volt 50 Amp NEMA6-50P socket , such as:

Pardon our interruption...

 

[trigger3]

im not entirely sure thats true...im in the uk too, but i think that all single phase in america is the same plug. im sure ive seen welder review videos where they have tested 110 and 220 on the same machine and just swapped to a different socket. i may be wrong though but realistically, the machine should either be able to sense the voltage or have a switch to change over anyway

in the usa the common single phase is 120/240 . 122/245 to be exact (atleast at my house). the plugs are entirely different. dual voltage machines typically have auto sensing internally with a adapter plug so it can be used on 120 or 240 outlet