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small electric motor repair question

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  • small electric motor repair question

    SO I got one of those wood stoves with the duel motor fans, the engineer that invented this mess should have taken one ride in a twin engine with the rpm's out of sync and he would have immediately $hitcanned the hole idea,,, even though it's cold as hell outside I tore into it to save whats left of my sanity,,,

    anyways - got everything balanced as best as I can and just cleaned out the motors little "end blocks" that support the sintered bronze bearings and have that fluffy stuff around it to transfer the lube, im wondering what type of lube one uses, do I have to make a special run for non-detergent or can I just use high quality synthetic car engine oil, or 3 in 1? she's going back together cuz it's 18 degree's here so any immediate reply's would be helpful - thanks

  • #2
    A fine machine oil is best, if you have 3in1 then I would use that, just a couple drops though as too much will just turn to lint and dirt trapping goo where you dont want it.


    • #3
      Hi John thanks - but they have about a 1" by 1" block of felt encased in sheet metal like,,, they need total saturation im thinking that's why so much felt - I know it will attract lint but a couple drops will wick away from the bearings and dry out in no time,,, half the fans air passes by these and dries the bearing out - I just got done sealing off the sheet metal parts with silicone so it won't leak out,,,

      on the oil, I don't know if I have any 3 in 1 oil handy but Im thinking ATF would not be a bad choice, I used 90 wt the last time and while it lasted for years I think I gunked them up - just cleaned everything with gas and then brake cleaner...


      • #4
        I think 3 in 1 was always recommened as Jon Heron posted.


        • #5
          I will pick some up and add to the ATF - I had to get it going so used a little to start with but will add the majority later - right now they are singing a tune and im heating up the house to normal temps - even the dogs were shivering a little cuz Ole pops wouldn't budge the thermostat past 62 f was really getting some dirty looks from the two of them

          thanks for the info


          • #6
            3 in 1 makes a SAE 20 oil specifically for electric motors. Real hardware stores sell it.
            Don't use ATF- it attracts dust like crazy.


            • #7
              Yes, 3 in 1 electic motor oil. Blue container, not the black one...but here are a couple of others if you can cross reference them: Stanoil 35, Gulf Crest C. (Bodine Electric Co) For use in their sleeve bearings.


              • #8
                I should learn not to second guess myself --- now I know why I went the 90wt, the sintered bronze bushings have excessive clearance - I used the 90 wt to keep them from rattling and shimmying --- the ATF worked well till it heated up and got thin - now these two motors are driving me nuts again but even worse than before...

                anyone who owns one of these types of stoves will know just what im talking about,,, really takes away from having a nice fire...

                back to the drawing board, I want to just $hitcan the whole thing and put one large variable control fan right under the stove _ I have the room but I will have to cut into my cement base and it's built like a brick $hithouse...


                • #9
                  If you are REALLY stuck, air tool oil should work just fine.
                  Duffy, Gatineau, Quebec


                  • #10
                    There is always the option of fitting new Olite bushings to take up the additional clearance that the old ones now have, that is if the old fan units are worth rebuilding. I've done this a few times in order to save a hard to source electric motor.
                    As you know once the clearance gets excessive there is only so much that the lube can do to prolong the inevitable. I too have tried different lube cocktails in order to prolong the life of this type of bushing. Sometimes one can put off the replacement date to a more convenient time. You'll know when.

                    A lot of info in regards to lubricant types and re-lubing of Olite bushing in the link below. I've bookmarked this page as working with Oilite comes up so often for me.
                    Oh, and also some good info on proper machining techniques when working with Oilite stock.


                    Standard Oilite® bearings are impregnated with a highly refined mineral oil to ISO VG (SAE 30) having a high viscosity index and containing anti-oxidant, anti-rust and defoamant additives.
                    To prevent possible seizures with stainless steel, hard-chromium and nickel plated shafts, an addition of molybdenum disulphide to the impregnation oil must be specified.
                    Any particular application thought to be outside standard conditions should be referred to our Technical Department.
                    However, here are some basic rules:
                    1. Low viscosity oil for low temperatures, high speeds or light loads
                    2. High viscosity oil for high temperatures, low speeds or heavy loads
                    3. High viscosity index oil for wide variations in operating temperatures
                    4. Oxidation stable oils for long-period usage
                    5. Oil with 'oiliness' additives for boundary conditions
                    6. Oil of lesser 'oiliness' for full film (hydrodynamic) conditions
                    7. Oil with Extreme Pressure (E.P.) additives for very heavy or shock loads

                    Home, down in the valley behind the Red Angus
                    Bad Decisions Make Good Stories​

                    Location: British Columbia


                    • #11
                      Sounds like the bearings are egged-out. They SHOULD have a very light oil in them. heavy oil doesn't move well .

                      They are supposed to let some oil out to form a regular oil wedge, but that depends on having a light enough oil to move through the pores well. I have had good results with the "zoom-spout" oil that is at some hardware stores. Marketed by SUPCO (Sealed Unit Parts Co.), although it is a little on the heavy side for some.

                      90wt? Likely not my first choice. Sounds like you need to pull the bronzes and replace them, then make sure lots of oil is in there.

                      I assume the shafts are doing their "lets run around inside this big hole" thing. It makes an annoying noise, worse because you know the noise is also the sound of them tearing themselves up even more. I have had some blower fans do that. But after being oiled up with the SUPCO oil they generally are good.
                      CNC machines only go through the motions.

                      Ideas expressed may be mine, or from anyone else in the universe.
                      Not responsible for clerical errors. Or those made by lay people either.
                      Number formats and units may be chosen at random depending on what day it is.
                      I reserve the right to use a number system with any integer base without prior notice.
                      Generalizations are understood to be "often" true, but not true in every case.


                      • #12
                        hey JT thanks and good info - it's nice to know they do allow a little variation for different conditions cuz I just gooped them with 90wt and they are back to getting full throttle without a wimper,,,

                        im in agreement that this is no long term solution but maybe when Im not needing the stove much I will tear into it again and try to do something with it - then again when you don't need it your onto fixing something else that you do --- at least that's how it seams to work for me,,,

                        anyways - Im kicking around making up a jig that I can press the existing bearings (end per end) and have a makeshift shaft in them that's undersize and try to get the sintered bronze to "re-conform" - then I could use regular oil in them without worries for awhile,,, what say You? worth a shot maybe as the outer diameter is huge and I really cant see them going anywhere but reducing the ID....

                        forgot to add - they are specialized bearings integral with specialized mounts, they will need to be replaced as a unit... all I can get to is the ends...
                        Last edited by A.K. Boomer; 12-05-2013, 10:39 PM.


                        • #13
                          Update, the cracked stove glass thread made me dig this one up as i did not want to corrupt his op,

                          My OCD kicked in and I indeed $hitcanned the twin out of sync clapped out motors from hell,
                          I found an awesome larger single commercial blower and motor unit and it mounts in the basement and takes it's intake charge off the cold air intake plenum, I have a built in anti-back flow valve for extra safety,

                          the unit purrs like a kitten and im so happy I went though with all the work...

                          and the heat is so uniform and now due to pulling the intake charge out of opposite ends of the house, I don't have to even run the ceiling fan that was in the same room and was also starting to make noise... what a diff, what an improvement.

                          it's a heavy gauge squirrel cage fan unit with a magnetech motor with oil ports and yes I went out and bought some 3N1 oil and stuffed some down there.

                          bought the unit at a local re-store shop for 7 bucks and it's almost like new... very happy now...