How I fixed my MIG welder after one of the diodes in the bridge rectifier failed

hi everyone this is a quick video on some tips if you want to fix your welder if it randomly goes bad and starts making weird noises this here is a regular MIG welder when you open them up they're fairly simple on the inside there's not a whole lot of components you've got to transform a down here and some other things in this and so for what usually happens if these goes bad is this thing in here this is what converts the AC to DC this welder is 240 volts ac and it will convert 230 volts DC and in doing so the current goes up and obviously you know the the voltage goes down but what how this works this is called a rectifier bridge it's really important to understand how the AC gets converted to DC if you want to fix this what happens in here is what happened to me is those we see these these things right here one of these went bad from the original manufacturer and it's quite common that they're not they're very inexpensive and they will pop and break so what I've done is I've ordered some replacement they're called their diodes I've wanted eight replacement dyes to replace their original ones and wide them wired them back together like the original ones were and put them back in but what you need to understand is the way the current flows and in this in in a situation like this and there are other variants of how this is setup in other worldís but for this particular world what happens is the AC legs come in on this plate and this plate so AC will come in here then AC will be coming in here if you like to think of it as because IC is a fluctuating up-and-down current so it'll go in here then go in here go in here then go in here what has to happen because all the current has to flow from these two plates towards this central leg here which is connected in the middle and you can see there are insulators that inch lay between where the two ac poles come in little ceramic insulators down there so that what happens actually comes in here it goes through this and another one which is on the opposite side of it on the bottom and flows through this way and up into this this positive leg which then goes to the big torch and after it flows through the big torch comes a you see the red wire goes in there ends up coming back on the negative side back through this transformer and back up into this position here so what happens is as the AC current flows out of that leg it goes all the way through the torch comes back it comes back into this plate here which is joined by this this bar across to this plate here so these two plates receive the return current and if that then flows back through this diode here and one on the opposite side as well as this diode here in this node here back towards where it came from originally on the to AC legs so I'll show I'll link a picture of this and also a video of a guy who I keyed off to to UM to do this but what I ended up meeting was 8h FR diodes they were called i'll link to those to a place that eight that i had in the video I watched he used regular diodes like this but also some which you see a little arrow there which just suggests the way that the current flows he had so much went the other way but in this my setup they weren't useful you actually needed eight of all this same type so you could have always have the current flowing from this just think of it as flow from outside to inside so it flows from here through here back up into here and back through this diode and into the into the positive so this is um this is uh I was just had it working which is really nice because this is quite an expensive MIG welder I hope this video might be useful for people who are trying to fix this

Channel: Ian Peters

Views: 7,953

Rating: 4.9384613 out of 5

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Id: gQD6YJHHEGs

Length: 4min 0sec (240 seconds)

Published: Sun Nov 10 2019