Announcement

Collapse
No announcement yet.

Miller 330 A/BP build date

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • #91
    I have a couple of old 600v ceramics in my capacitor trash pile which test out correctly on their printed values. The problem is they vary anywhere from .02 to .07uf and not enough of any value to do all 4. Would it be a problem to have this range of values paralleling the rectifiers, if they are not all the same? My suspicion is probably not, but would like some comments from people in the know.

    Comment


    • #92
      It's probably not a huge deal, but I would feel better if they were at least all the same value. A diode bridge is a balanced entity, and you will drive unbalance in relation to transients and/or any ringing that might occur by having different values. I, probably like you, have hundreds if not thousands of capacitors lying around in junk boxes, and it just seems natural that out of all of them, you can't find four the same! :-)

      If it were mine, I would get 4 identical capacitors, but I'm not smart enough to say what the risk is of having it "unbalanced"--never considered it before. Miller chose the value they picked for a reason--I doubt it was just whatever happened to be lying around. Caps like this are really cheap, so I'd buy some.

      Comment


      • #93
        I’m going to pull that machine out here in a little bit and take those pictures you want. Sorry I didn’t do already, had some work that I needed to get done.

        Comment


        • #94
          If it’s this doofloppy, I can’t make out any writing on any of them.
          Attached Files

          Comment


          • #95
            I’m going to get in there with a tag and maybe some spit and see if I can get the grime off.

            Comment


            • #96
              This is one from the other side after a little spit shine. Hope you can read enough of the numbers. I have no idea what they mean. The other thing, the cylinder looking one, I can’t make out a single thing on it, even after the spit shine.
              Attached Files

              Comment


              • #97
                Originally posted by ryanjones2150 View Post
                I’m going to get in there with a tag and maybe some spit and see if I can get the grime off.
                That's the one alright. Looks like Miller liked to use disc capacitors. Don't worry about the values as they are listed in the exploded parts illustration that Aeronica41 posted. Since I don't have all the same value capacitors, I am going to series connect two .022uf/200v mylar capacitors to get to the .011uf/400v rating. As for the .05uf one spanning the rectifier assembly, I will substitute two .1uf/200v capacitors in series.
                The preferred route would have been single units but the retail outlets for electronic parts seems to have vanished into an abyss. It's internet, or nothing nowadays, and don't want to wait for another 2 weeks.

                Comment


                • #98
                  Originally posted by ryanjones2150 View Post
                  This is one from the other side after a little spit shine. Hope you can read enough of the numbers. I have no idea what they mean. The other thing, the cylinder looking one, I can’t make out a single thing on it, even after the spit shine.
                  Ok, you got that post in just a hair before my previous poste, that confirms the values that I have in hand. Much appreciated effort on your part.

                  Comment


                  • #99
                    Originally posted by 07wingnut View Post

                    That's the one alright. Looks like Miller liked to use disc capacitors. Don't worry about the values as they are listed in the exploded parts illustration that Aeronica41 posted. Since I don't have all the same value capacitors, I am going to series connect two .022uf/200v mylar capacitors to get to the .011uf/400v rating. As for the .05uf one spanning the rectifier assembly, I will substitute two .1uf/200v capacitors in series.
                    The preferred route would have been single units but the retail outlets for electronic parts seems to have vanished into an abyss. It's internet, or nothing nowadays, and don't want to wait for another 2 weeks.
                    Sounds good--should work. I did see the caps Ryan photographed were 500 volts, but I still think 200-400 volts should be OK. You will be good with those in series.

                    I feel your pain on internet-only for parts. We have had a fantastic local electronics parts/hobby/network store about 5-6 miles from my house since about 1980. Pretty well stocked with parts, and while not exactly cheap, they were not out to rip you off, either. And they probably could have, just because they were the only source within nearly a hundred miles. Decent guys. They announced last week that the owners are retiring and closing up shop. I went today for one last stock-up trip, and the place is almost empty already. There are no other parts places anywhere near within reasonable driving distance, so it's the end of an era for me.

                    Comment


                    • Great thread, guys. I'm mostly clueless about what you're talking about, but glad to see you share it with the forum, and I plan to save it all for future reference for my own (1978 year model) 330.

                      Comment


                      • Just finished installing the bypass capacitors across the new power rectifiers. As you can see, each bypass capacitor is composed to two in series to get the correct value of .01uf or to be more exact .011uf. Tomorrow the whole assembly will be installed. Note that the heatsinks will be hot (ie under power) but mounted to the frame with insulated fibre angle (what do you call those when they are not iron, as in angle iron) , I suppose angle fibre. Anyhow, here is a shot of the mounting fibreware (or hardware) and a couple with capacitors installed. Click image for larger version

Name:	Millerdiodes2.jpg
Views:	88
Size:	350.0 KB
ID:	615546 Click image for larger version

Name:	Millerdiodes3.jpg
Views:	73
Size:	220.0 KB
ID:	615547 Click image for larger version

Name:	Millerdiodes4.jpg
Views:	71
Size:	322.5 KB
ID:	615548

                        Comment


                        • They must be angle fiber if they're not angle iron! Anyway, that's a great way to get the insulated mounting you need.

                          Lookin' good. Just be sure to leave enough space between the heat sinks so that if something conductive gets in there, it can't short between them. I'm envious of those heat sinks--really nice, and pretty pricey if you had to go out and buy them.

                          Comment


                          • Originally posted by 07wingnut View Post

                            That's the one alright. Looks like Miller liked to use disc capacitors. Don't worry about the values as they are listed in the exploded parts illustration that Aeronica41 posted. Since I don't have all the same value capacitors, I am going to series connect two .022uf/200v mylar capacitors to get to the .011uf/400v rating. As for the .05uf one spanning the rectifier assembly, I will substitute two .1uf/200v capacitors in series.
                            The preferred route would have been single units but the retail outlets for electronic parts seems to have vanished into an abyss. It's internet, or nothing nowadays, and don't want to wait for another 2 weeks.
                            Just a note for anyone who may be looking at this thread in the future--as wingnut indicates, when you add capacitors in series, the capacitance goes down, but the voltage they can handle goes up. So the two .022 mfd, 200 volt caps in series are equivalent to a .011, 400v cap. Resistors add when in series, but capacitors do the opposite. 1/Ctotal = 1/C1 + 1/C2.

                            Comment


                            • Ryan and I were furiously sending photos and texting back and forth today, working out replacements for the other four selenium rectifiers in 300 amp 330A/BPs (three in the 200 amp version), since he had Helga's covers off for the photos. These other four create DC control voltages for relays, etc. in the machine. The main weld rectifiers are the ones wingnut is working on. I think we have found a single 2-5 dollar part (depending on where you get them) that will work for all four of them, but I need to verify the specs with Miller Tech Support tomorrow. Will post when the part is confirmed.

                              Comment


                              • I’m glad that you have it under control, because what I was looking at on my end had my eyeballs spinning in their sockets! My machine doesn’t have the big mean selenium doofloppy like wingnut’s, but I’ve already had Miller tech tell me I needed to replace those smaller ones over top of the relays. Thanks to Wayne for sorting out the wires running everywhere....and thanks to miller for stamping numbers along the length of each wire in that machine!

                                Comment

                                Working...
                                X