Onan Generator Surgery

Discussion in 'Off Grid Living' started by BenP, Aug 21, 2020.


  1. Cruisin Sloth

    Cruisin Sloth Special & Slow

    You will need to put the back end back on , and use a tool like we use with wood lathes ,, I have done that a few times on some stuff, go slow and short sleeves and no rings or watches , move slow and practice before its running . I used the brush holders as a rest , very fine cuts and a file , I also had a jump wire from tool to base ground.. Be very careful ,
    Sloth
     
  2. HK_User

    HK_User A Productive Monkey is a Happy Monkey

    HK
    Below is the preferred ways.

    In your case a cutting stone is about as good as you can expect unless you can tear it down far enough to fit in a lathe.
    HK

    OTOH A good option is a scotch bright pad.

    3M 7447 General Purpose Hand Pads
    [​IMG]

    [​IMG] Enlarge
    Conforms to uneven surfaces. Lasts longer than steel wool.
    • For final finishing or light cleaning of metal and wood.
    • Can be used with water and solvents.
    • Maroon fine-grade aluminum oxide.

    HK insert>
    First you will need to rig someway to rotate the unit at a fair speed.
    Cut the scotch pads into a length and size to fit the individual ring.
    Be careful about using other types of abrasive cloth as many will embed the cutting material into the copper and act as a grinding source to destroy your NEW brushes. The Scotch Bright Pads will scratch glass so used carefully they will take off enough surface to reclaim the slip rings.
    Restore all Slip Rings at the same time to a bright shine.
    Replace all brushes and springs and figure out the cause as even a small amount of grease thrown from a bad bearing can cause this to happen,
    Use mineral spirits to clean all surfaces before you start.
    Clean brush holders to ensure a free float brush contact and check continuity at each point.
    Dry well for 24 hours and use a dial indicator before and after to check your progress.

    HK close<


    5.9TECHNICAL HANDBOOKCollectors should be smooth and true. A collector which is in bad condition should be reground or turned. In general commutators with a TIR (Total Indicated Reading) of greater than 75μm (0.003”) and/or to bar variance of 7.5μm (0.0003”) needs to be reground or turned.If it is impossible to regrind a worn collector, a collector grinding stone can be used to reduce flats, ridges, high mica and rough spots. In this way the performance of the machine may be improved sufficiently to allow continues operation.Methods for reconditioning collector A commutator or slip ring surface can be reconditioned in any one of seven ways, although other methods have been used in emergencies. The recognised and approved techniques are listed below in order of preference:1.Turning with a diamond tipped tool2.Turning with a tungsten carbide tipped tool3.Grinding with a rotating wheel4.Turning with a tool of normal high-speed steel5.Grindingwitha‘fixed’stonemountedinatoolrest6.Grinding with a handstone7.Scouring with abrasive cloth.
     
    Last edited: Aug 30, 2020
    BenP likes this.
  3. techsar

    techsar Monkey+++

    The scotchbrite pads normally are great for cleaning up surfaces, but given the flat on the slip ring, a small file or other solid cutting tool is going to be desired.
     
  4. HK_User

    HK_User A Productive Monkey is a Happy Monkey

    That's where the stone comes in.
    This can be purchaseed in many grits from a motor rebuild supplier of such tools.
    As yet we have no knowledge how large the flat/out of round is and that is the first thing we need to know. That's the reason for the dial indicator for the ring must be as round as possible and you need to know how out of round it is before you try to repair it and others.
    Believe me the pad material will cut the copper and not leave a rough surface as a file would if it chatters even once.
    Files are out of place on this type repair.
    https://www.mersen.us/sites/us/file...lectric-machines-maintenance-tools-mersen.pdf

    Tools for maintenance of electrical machines GRINDING STONESThe commutator or the slip rings of an electrical machine must have a proper roughness to give the carbon brushes an adequateseating base and enable them to ensure a good current transmission. To achieve this proper roughness, the commutator or the slip ring has to be «ground» after machining with a medium grinding stone such as P/N 90623N. If you wish to work without dismantling the machine, rather use a grinding stone with a handle. P/N90602N is ideal for motors up to 15 kW, while P/N 90651N is suitable for motors up to 150 kW. For bigger motors, use P/N90612N or 90607N, which are larger. Our grinding stones have four different grain sizes, each adapted to the work to be done. These stones are suitable for copper,bronze and steel. • Coarse grinding stone (C): with big grains, it does not erode much and is good for removing large quantities of material. • Medium grinding stone (M): with an average grain size which is suitable for removing minor defects, it is recommended forfinishing any commutator or slip ring machining. Its grain size is designed for achieving the right roughness for a good brushseating base and film deposit. • Finish grinding stone (F): with fine grains suitable for commutator cleaning or for achieving the right roughness on certaintypes of soft copper commutator. • Polish grinding stone (P): with very fine grainsTwo-grade combination grinding stonesGrinding stones with three-position adjustable handle and thrust knob Single-handle grinding stones. The handle is mounted lengthwise.Double-handle grinding stones. The two handles are mounted crosswise. Tower-type grinding stones for commutators and slip ringsTwo-grade combination grinding stone Grinding stone with adjustable handle Single-handle grinding stone Double-handle grinding stone Tower-type grinding stone 4 Reference Dimensions in mmGrain90608N50x25x200 C/M90607N50x25x200 M/FReference Dimensions in mm Grain90612N50x40x50 M 90611N50x40x50 F Reference Dimensions in mm Grain90613N130x80x50 C 90614N130x80x50 M Reference Dimensions in mmGrain90618N100x200x80 C 90619N100x200x80 M Reference Dimensions in mmGrain90635N20x20x80 C 90637N 20x20x80 M 90636N20x20x80 F 90621N25x40x160 C 90623N25x40x160 M 90622N25x40x160 F 90629N25x40x280 C 90631N25x40x280 F 90627N50x50x200 C 90625N50x50x200 M 90626N50x50x200 F 90640N30x30x200 C 90641N30x30x20
     
    Last edited: Aug 30, 2020
  5. Dunerunner

    Dunerunner Brewery Monkey Moderator

    I would never try to turn an armature unless I had the proper equipment. On ship, it would go right to the rewind shop. It needs to go onto a lathe, otherwise you risk the compounding of the problem IMO.
     
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  6. HK_User

    HK_User A Productive Monkey is a Happy Monkey

    The armature is not bad and I would never touch a armature with anything but a lathe and an experienced machinist as the wrong speed, angle of cutting tools and availability to use a undercutting tool is what is needed in that event.

    Wrong speed, wrong cutting angel, wrong machinist and you end up with a solid armature, totally useless.
     
    ghrit likes this.
  7. HK_User

    HK_User A Productive Monkey is a Happy Monkey

    My shop right now, a bit dusty but still in good repair.
    Motor turning lathe with undercutting tools.

    DSCF5267 (2).JPG

    Junk motors beyond economical repair on the steel rack.
    DSCF5270 (2).JPG


    Steel motor housings used with permanent magnets.
    DSCF5271.JPG

    Press in shop to properly install bearings, no Hammer Zone.
    DSCF5268 (2).JPG
     
    Last edited: Aug 31, 2020
  8. Dunerunner

    Dunerunner Brewery Monkey Moderator

    @HK_User Maybe you could PM Ben P and arrange to meet? Unless you and he are on different sides of the planet.
     
  9. HK_User

    HK_User A Productive Monkey is a Happy Monkey

    What I first want is for the unit to be put back together.
    Then a Oscope on the output.
    All we have now are static readings which are good if the leads between each coil is opened and coil readings taken.
    A flat spot would show up on a Oscope but it would only be a wiggle on the output of the phase affected.

    Ben P is half a world away and in flood conditions now!
    He has an open coil or no power to it.

    Ben needs to go to the junction box, take readings static and running and refer them to a print.
     
    Last edited: Aug 30, 2020
    BenP likes this.
  10. Dunerunner

    Dunerunner Brewery Monkey Moderator

    :( That didn't go well....
     
    BenP likes this.
  11. Cruisin Sloth

    Cruisin Sloth Special & Slow

    Yes Lathe is best , As I have done when at my shop . But in sandbox/ MIL time (other places), i have done slip rings reshaping , Commutators with tool bit and file then undercut Com .YMMV but i know my ability till i don't .
    Just replaced a battery, vibrator/ring on an Iphone 7, screws are so small , i needed mag glasses of 3 power and bright lights ..Used tweezers and the smallest pentilope drivers (.5 size) ever. Don't ask how long it took , 50 years ago i could see and not shake as much .
    Sloth
    Edit Add
    Do Not tell me I can't !
    I still Fly them killers , many know nothing , r-wing can be safer than Fixed ..
    R class ! and many versions to Diagnose them !
    1.2mm screw is a pin head WITH THREAD ,blue lockite in on a 3 vane pentilope driver.
     
    Last edited: Aug 31, 2020
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  12. HK_User

    HK_User A Productive Monkey is a Happy Monkey

    Sure it did, just part of trouble shooting.
    One step at a time.
    Of course I'm not sure about the flood but just know where the Hurricane was suppose to go next.
     
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  13. BenP

    BenP Monkey++

    I ordered a new collector ring on fleebay, I might see if there is a way to move the brushes back, they all seem to be riding a little forward on the rings.

    I'm in Kentucky.
     
    Last edited: Aug 31, 2020
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  14. HK_User

    HK_User A Productive Monkey is a Happy Monkey

    Yup, how's the rain?
     
  15. BenP

    BenP Monkey++

    The rain has not been bad. It rained on and off most of the morning but we needed it.
     
    HK_User likes this.
  16. BenP

    BenP Monkey++

    I cannot get the rotor/armature off of this thing, it has a hollow shaft with a threaded rod going down the middle. The manual does not say how to disassemble it and I have beat and pulled on it enough to know it is time to seek assistance. Has anyone messed with one of these?
     
    HK_User likes this.
  17. ghrit

    ghrit Bad company Administrator Founding Member

    Have a look at the engine end, see if there's a clue on the end of the crank (common) shaft. Consider also that there might be some left handed threads involved depending on which way it spins. Sure would be nice to have a shop manual for that thingus.

    As far as turning the rotor ON the machine, that would be a really bad idea. A really skilled machinist with the right type of lathe might try it after a couple fingers of scotch, but he ain't the guy you want.
     
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  18. Cruisin Sloth

    Cruisin Sloth Special & Slow

    On some i have seen , that long bolt /threaded rod going down the middle is the unit that is used as a pusher on the crank or rear of the engine . The rotor/armature has a Morse taper female and the engine is male ., so you need a puller to pull on the rotor/armature and push on the rod , use heat on the point of where the front of the rotor/armature meet the engine ,
    That should pop the two apart .On assemble that rod nut is the last to be tightened after all is put back on so the end bearing is centering the shaft and the taper is allowed to align straight .
    Sloth
     
  19. BTPost

    BTPost Stumpy Old Fart,Deadman Walking, Snow Monkey Moderator

    The Resident SmartGys over on www.smokstak.com in the Onan forum recommend tapping the rotor end of the shaft and screw in a Zert Fitting and then using a Grease Gun to pop the rotor free...
     
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  20. Cruisin Sloth

    Cruisin Sloth Special & Slow

    That might work also , messy but I have pulled pistons out of calipers like that also...
    Sloth
     
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