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Mvp wiring - smoked

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  • Mvp wiring - smoked

    Ive been running my 211 on 110v and swapped to 220v today. Nobody sent me the memo that the Miller MVP reverses the black and white wire for 220v so it smoked the fan. Anyone else ran into that issue hardwiring a 220v direct line? I’m waiting now for a new fan to come in since the welder uses a 24v signal from the fan to turn on.

  • #2
    Here's what I figured out when working on one about a year ago...


    • #3
      Very detailed thread, and quite far away from my question. Interesting read though!

      “has anyone encountered having the issue where you must reverse the black and white wire coming in on 220, else you’ll smoke the fan?”


      • #4
        We'll, the posts discussed several board components which might have been affected. And my troubleshooting ran down an issue where 48V was sent to the board, which happens when you "reverse wire." There should actually be four wires going into that machine - green (common to 120V and 240V inputs, it's Earth ground), red (connects to the hot lead on 120V or 240V), white (hot lead on 240V only), and black (neutral lead for 120V only). I took this info straight out of the operator manual.

        I once sent a flood inundation map to someone who replied that it wasn't useful at all and he instead needed a map that showed where all of the water would go in case a dam failed...


        • #5
          The welder is fine. I don’t need anything internal. I’ve been told the MVP plug reverses when in 220 mode. Local welding repair shop said so, looking for verification. This would only flip the white and black, leaving the common untouched. My focus is on the plug. I’d like to know what wires are for what pins on the plugs. I can see the crossover inside the welder when going from 110 to 220. Instead of using the white, it should use the red (4th wire) which leaves the black alone - contrary to other info.

          Last edited by One1; 10-04-2019, 08:57 PM.


          • #6
            Page 36, section 7 of the operator manual, left side.


            • #7
              So to anyone who has taken the plug and used a multimeter, verify the 220 connection would come in on the red wire instead of the white.


              • #8
                Here's what it looks like in the technical manual. You have 230V across the red and white leads. 120V goes across the red an black leads. When you energize across the Red and White leads, it actuates CR3 (NO, so it closes and connects 240V across the entire transformer) and CR5 (NC, so it disconnects the 120V neutral from mid tap). What you did was put 240V across half the primary, which sent 480V to the fan and 48V to the board. Good thing the input rectifiers, filter cap, and voltage regulator handled the 63V DC across them. If you want to use your multimeter, you won't get a reading to the 240V tap on the primary because it goes through a normally open (NO) relay.

                Fortunately, CR1 prevented you from doing major damage to the power components. That would have been an expensive lesson to learn to read the operator manual, particularly before modifying the machine.

                Click image for larger version

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                • #9
                  Sigh..... same thing that’s sitting here inside the welder. I’m not responding further unless the original (only) question is answered about the plug by someone (else that’s going to listen to me say I’m asking about a plug not a welder). Thanks.


                  • #10
                    Thank the lawd...... weldfever answered the question with this video. The wiring is not stock and the wire colors are wrong. /end.



                    • #11
                      Ok, it's my last attempt to help. Don't follow that video.

                      Weldfever's video was of a Miller Dynasty 200, which is an autoline machine that operates way differently than your machine. In the Dynasty 200, it receives any voltage on the SAME inputs and boosts that voltage to a DC buss of 810V through a PFC boost input section (I know because I have repaired two that had that circuit), so it doesn't matter what voltage it sees. Your machine connects/disconnects different input leads or at least connects them in a different configuration based on. Your Millermatic 211 MVP does this by having DIFFERENT leads for 240V and 120V, all handled mechanically in the plug. I know this because I spent a lot of time going through that machine. I ultimately sold it because I didn't like the unreliability of the relays.

                      I am still trying to understand what you mean by reversing the black and white wires. With your cover off, both of the 240V hot leads should go to the input switch terminals. When wired for 120V, the neutral lead did not go to the power switch, and rather went straight to the board, terminal RC-4. The easiest way to tell you have it right is to check continuity from your plug's hot blades to the wires on terminals RC-10 and RC5 when the switch is in the on position. These terminals are along the top edge of the board on the right. Terminal RC-10 should have a white wire on it (far left) and RC-5 has either a red or maroon wire on it (second from the right). It doesn't matter which plug blade connects to which terminal.

                      I hope this helps.

                      Last edited by jjohn76; 10-04-2019, 11:50 PM.


                      • #12
                        You haven't listened to me this whole thread. I asked about a plug for a specific reason, and you just don’t wanna accept that. It doesn't Matter how they did it. All that matters is that my cord isn’t factory and the colors are wrong and that’s all i care about. I have the wiring schematics, I don’t have an mvp plug. Since the mvp drops the black and adds the red, a non factory cord isn’t going to show me anything if the unit they used is sealed and had a diode. As i said before, that video showed me what i want to know, which has nothing to do with the tea price in china about the welder. There’s nothing anyone can do if the diode prevents reading the plug and there is no name on it. Probably chinese, I’ve never even seen an mvp knockoff. I’ve since tossed it all and rewired the whole shebang.

                        NOW I’m going to be addressing the welder, but only since it’ll be 3 days before my new fan comes in and i can test it myself. This fan has a lead wire for 240V and a lead wire for 120V according to the tech I spoke to yesterday and if that’s the case I can probably put this thing back together now but I’m not certain. Because I have an open circuit between black and blue and a closed circuit between black and red reading 29 ohms standing still. Since black and blue is giving me nothing I’m assuming that’s the part I smoked and it’s the 110v side. I still have inductance going through black and red and inductance going through the white 24V control wires. As long as this fan will operate in 220V mode by feeding the fan through the black and red wires and ignoring the blue, i can get back to business. If the fan depends on both red and blue having voltage at the same time, it probably isn’t going to work. The wiring schematic is vague.

                        Last edited by One1; 10-05-2019, 09:16 PM.


                        • #13
                          Here's your pail and shovel.
                          Sandboxes 7 and 19 are available.
                          Don't eat the tootsie rolls in the sandboxes.
                          Have a nice day.


                          • #14

                            fan video
                            Last edited by One1; 10-05-2019, 09:59 PM.


                            • #15
                              And for good measure, a perfect board with zero heat on it after the wiring issue. I thought these boards were fragile?! Lol. Seem pretty solid to me!

                              Running black and white at 220 instead of red and white........ perfectly safe, if you have a spare fan.
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