Announcement

Collapse
No announcement yet.

Oil filled submersible pump. Which oil?

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

  • Oil filled submersible pump. Which oil?

    So I seem to have acquired this elderly, rusty horizontal bandsaw project which I hope to bring back from the dead, and it came with a Little Giant coolant pump (Model 2E-NT, apparently now obsolete). The pump does not look like it needs more than a cleaning and a new power cord - the old one was worn / broken off 1/2 an inch from where it entered the pump. However, I also discovered to my messy surprise that it was oil filled, and now I'm wondering what the correct type of oil will be to refill it with after I replace the cord. (And the seal around the cord, and what I take to be the oil fill plug...)

    I have not called Little Giant (yet) but I thought perhaps someone here knew what these things are filled with? (And please don't tell me PCB oil!)
    "A machinist's (WHAP!) best friend (WHAP! WHAP!) is his hammer. (WHAP!)" - Fred Tanner, foreman, Lunenburg Foundry and Engineering machine shop, circa 1979

  • #2
    Dielectric oil like Mobil Univolt.

    Comment


    • #3
      Thanks! That was the magic search term I needed. I now know what I need and have some leads on where to find it.
      "A machinist's (WHAP!) best friend (WHAP! WHAP!) is his hammer. (WHAP!)" - Fred Tanner, foreman, Lunenburg Foundry and Engineering machine shop, circa 1979

      Comment


      • #4
        Originally posted by Rosco-P View Post
        Dielectric oil like Mobil Univolt.
        Cool, I had always wondered what kind of oil spilled out of my shopvac and submerseable pump onto my basement floor. (Yes, Both let go at the same time. Because one was inside the other, running unattended for 4 days straight.. Loss of water pumping didn't help the shopvac any)
        Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

        Comment


        • #5
          Hi Mickey: can this type of motor NOT run free in the atmosphere?

          Comment


          • #6
            Originally posted by mickeyf View Post
            Thanks! That was the magic search term I needed. I now know what I need and have some leads on where to find it.
            Also known by some as Transformer oil, try motor winding shops or local electrical supply house may offer a lead.
            Max.

            Comment


            • #7
              Originally posted by wtrueman View Post
              Hi Mickey: can this type of motor NOT run free in the atmosphere?
              Dunno about his in particular, but some rely on immersion in fluid for cooling.

              Some time ago, I worked at a place that used oil filled assemblies that were submerged in use and routinely subjected to very high external pressures ( 3000 psi not uncommon). These units were filled with oil, then submerged in oil and a high vacuum drawn over the oil surface to make sure all air was removed. Complicated process to make sure the unit didn't flood in service.
              Design to 0.0001", measure to 1/32", cut with an axe, grind to fit

              Comment


              • #8
                Any pure mineral oil will be fine.

                Comment


                • #9
                  Hi Mickey: can this type of motor NOT run free in the atmosphere?
                  I have no idea, this is the first one I've encountered. My working assumption is that the oil was there because it was part of the original design and that they wouldn't have gone to the expense if it didn't need it. I plan to replace it rather than run the pump without it. In any case, it won't be free in the atmosphere, but submerged in coolant.

                  Actually, I think that explains it. If there were no oil the motor would be inside a small sealed container with no way to lose heat except via the non-circulating air inside that box. The oil is able to transfer the heat to the walls of the die-cast aluminium box, and thus to the surrounding coolant, keeping the pump from overheating.
                  "A machinist's (WHAP!) best friend (WHAP! WHAP!) is his hammer. (WHAP!)" - Fred Tanner, foreman, Lunenburg Foundry and Engineering machine shop, circa 1979

                  Comment


                  • #10
                    The oil serves many purposes. Like mentioned, heat conduction. Since these pumps are shaft drive if the pump was full of air it would build pressure as it heated up and air might get past the shaft seal and when it cools it could suck in water. The oil also keeps the water out by being incompressible. Also it keeps the internal bearing and seals lubricated.

                    Comment


                    • #11
                      I suppose this implies that when refilling - which obviously was not intended by the manufacturer to be done by me the end user - as little air as possible should be left in. I don't have any way to vacuum seal this thing, but I suspect that what I am able to do will be "good enough".
                      "A machinist's (WHAP!) best friend (WHAP! WHAP!) is his hammer. (WHAP!)" - Fred Tanner, foreman, Lunenburg Foundry and Engineering machine shop, circa 1979

                      Comment


                      • #12
                        I tried working on one of these pumps before and gave up and just bought another due to the oil issues. I am guessing they are assembled under oil or something.

                        Comment


                        • #13
                          Did the pump fail after working on it, or were you just unable to reassemble it filled and sealed to your satisfaction?

                          I have nothing to lose but a bit of my time. I could even (manually, and messily) assemble it under oil, but I don't think that's the first thing i'll try. Since I had to destroy the original plug and power cord gasket to disassemble it I figured I'd re-tap for pipe plugs, adapt one for the sealed cord egress, fill through the other, then "cork in the bottle" at the fill hole.
                          "A machinist's (WHAP!) best friend (WHAP! WHAP!) is his hammer. (WHAP!)" - Fred Tanner, foreman, Lunenburg Foundry and Engineering machine shop, circa 1979

                          Comment


                          • #14
                            I worked with the superintendent of utilities for the Cowichan Regional District many years ago. In a discussion on submersible pumps, he had these gems to offer:- when dealing with sewage pumps, ALWAYS replace the seals annually or be prepared to replace the pumps. When servicing these pumps, ALWAYS refill them with vegetable oil, (did not really matter which kind, canola would do.) The reason for the vegetable oil was IF a seal failed, it was not recognized as a contaminant in the waste stream, while a mineral oil would cause all sorts of regulatory grief. At the voltages encountered, (maximum 575 3 phase,) and the temperatures involved, ANY oil would work. This of course was just an opinion based on several years of successful application. but what the hell would an old techy know?
                            Duffy, Gatineau, Quebec

                            Comment


                            • #15
                              It was mostly along the lines of "ugh. what a mess. aww, screw it."

                              Get another used one off ebay and forget it. Or better yet get a real coolant pump and use that.

                              Comment

                              Working...
                              X