Blew up CT312 welder today! Help with wiring

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Hi everyone - so I have owned this little cheapo 3-in-1 welder for 3 years now. Its worked ok but on 110 theres only so much one can do. Wired it up for 230v today and blew a cap / smoke pouring out of the thing-Specs says 110+230v  https://gnktools.com/catalog/manual/ct520d.pdf So.. I hooked up the 2 hot leads to each of the 110v wires (black and white basically) - I had to convert from a 4 pin 230v generator plug to a 3 wire 110v (came with the welder) - like the pic-Was i an idiot?

Last edited by SavedInChrist; 03-05-2021 at 09:55 PM.
Reply:Maybe.  Did you verify Line1 & Line2 had 240V between them, and each one to ground had 120V?

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Reply:Or maybe the manufacturer neglected to tell you there’s a jumper inside the machine that needs to be moved for 240v. operation?Miller a/c-d/c Thunderbolt XLMillermatic 180 Purox O/ASmith Littletorch O/AHobart Champion Elite
Reply:verified 240v yes .. (was still cycling down to 230v, i measured it right at start) - Looked inside - no jumper. Im going to replace the blown cap and try again on 110v, try and resurrect it - everything else looks ok (no burns/etc)
Reply:If this welder is a 115 / 230 volt welder. there should be some way to adapt to the different line voltages. There are two common ways to do it. The old way was the have some type of device to either manually reconnect and automatically  reconnect jumpers to match the machine to the line voltage used. The newer system uses a boost or PFC system. A switching transistor uses an inductor to charge a capacitor bank up to a set voltage. and the inverter runs off the voltage.I am going to guess you have a relay that pulls in on 115 volts and stay off at 230 volts. And it is stuck in the 115 volt position. This then caused the voltage to the capacitor to be double what is can handle and it exploded. Two caps in parallel on 115 and the two caps in series when on 230 volts. So look for the second cap the same size as the one that blew an check it. Both should be replaced and find the relay that reconnects them.
Reply:hi thanks yes ordered 2 replacements already - interesting cos i saw 4 caps there.. im pretty sure its a wiring thing - they are rated for dual voltage but not in the sense that one can easily switch - I think they come hard wired for either-I would love to figure out how to add a switch.. my elec exp is limited on the finer circuitry- no prob soldering in caps / etc-Would uploading some pics be of any help?
Reply:

Originally Posted by ccawgc

I am going to guess you have a relay that pulls in on 115 volts and stay off at 230 volts. And it is stuck in the 115 volt position. This then caused the voltage to the capacitor to be double what is can handle and it exploded. Two caps in parallel on 115 and the two caps in series when on 230 volts. So look for the second cap the same size as the one that blew an check it. Both should be replaced and find the relay that reconnects them.