Dc motor swap in south bend 16 lathe, pressurized bearings. - Page 4
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  1. #61
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    Quote Originally Posted by Homebrewblob View Post
    Bill my Sb bearing are round and actually smaller then the spindle shaft.

    There’s a tapered brass expander at the top that gets pulled up and out of the bearing to expand the bearing shell open allowing the spindle to fit.

    If you loosen the screws to that expander the spindle LOCKS right up solid, not because the expander interferes but because the ridged bearing shell clamps back down tight almost like spring steel.

    The expander is bolted solid to the top bearing cap with no adjustment.

    The caps are lifted with shims to pull the expander up causing the bearing shell to expand.
    "Relying a powerful heap on my memory" to quote Granny on being asked to klew Ellie Mae about sex, one Beverly Hillbilly skit..

    ....given I did this but ONCE, and about 1962..? The SB. Not Ellie Mae.

    By 1959-60 the 2 1/4"-8 was it? Spindle 10" "Toolroom" with all the decorative but useless flaking, there was a longish steel bar at top, rounded ends and two submerged cap screws to do the adjusting.

    When asked by other Students why I was always on the same week-installed plain looking roller-bearing Logan, not the "pretty" SB?


    "Because I have earned first choice."

    thermite liked this post
    Works for me!

    PS: YEARS go by.... scores-of... C&W Mercury Communications is established, UK.

    Old mate of mine from Bermuda is installed as MD. I look him up in the new phone book, and ring him up.

    He is not the most handsome guy around, wears a beard like cousin James Ewall Brown Stuart, nicknamed "beauty". "JEB Stuart" came later. Because back of his scraggly beard? He were anything BUT a "beauty"!

    "Ian? How the Hell did the MD end up with "666" as his phone extension?"

    "I got first choice!"

    Last edited by thermite; 05-08-2021 at 06:59 AM.

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  3. #62
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    I had a Bijur lubrication engineer come in and design a system to lubricate a fairly large spindle we were running a 50 HP motor on. OF course, it only ran at about 250 RPM. The lower spindle assembly ran on four angular contact bearings with about a 4" bore. The engineer calculated it only needed about 20 cubic centimeters of oil per minute to lubricate! We bought and installed the system they recommended ran it for about two weeks before the machine was shipped to the customer. This was forty something years ago. The machine was pulled out of production four years ago and went to scrap. Have no idea if this lubrication system lasted that long or if it had been replace with something else later in life. The fact here is, it doesn't require lots of oil to properly lubricate a bearing rather its a anti-friction bearing or a sleeve bearing as those found in a SBL headstock. Also, too much lubrication will kill a bearing, too! But if you are going to use pressurized lubrication, the bearing needs to be designed for this type of lubrication. The SBL headstock bearings as designed, are not designed for pressurized lubrication. I'm sure they can be altered for this type of lubrication. Ken

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  5. #63
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    When I say pressurized I mean the feed line, I donít plan to actually pressurize the bearing itself Per se.

    I just want to add a very low pressure feed to replace the lower oil feed wicks job.

    I would feel better if it can supply metered oil at a predictable rate.

    I also like the idea of this oil system PRE priming the spindle before starting to prevent dry starts.

    I think if I metered the oil and possibly enlarged the oil drain holes a bit (if possible) or even fitting large o-rings in the oil trenches as a barrier it could work.

    Iím no stranger to high oil pressure in a automotive engine, the high oil pressure tends to push the rod bearing off center causing contact with the crankshaft on the opposite side.

    Iíve seen a recently REBUILT engine that had a stuck oil relief valve and it smoked all 4 rod bearings.

    Mains were fine (as good as they could be in that situation)

    I donít want to pressurize the bearings Radially, they would spray out the gaps!

  6. #64
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    Ultra precise speed control? Synchronous motor. If you can find one for less than two grand.



    Otherwise 4-1/4 hp 130VDC treadmill motors go for about $70. You'll have to engineer one hell of a speed controller to make a cheap PM motor like that do what you describe though. More trouble than it's worth if you need precision.

    Your most realistic option is a VFD capable of closed-loop control and a three phase induction motor equipped with a shaft encoder. Closed-loop DC will work too, but don't expect it to be any cheaper. High quality DC motors and their controllers are spendy buggers. DC offers more torque on the low end, but DC motors are still limited by thermal constraints just like AC motors - bog them down and they'll suck down more current. Heating of a fixed resistance (your motor windings) is exponentially proportional to the current flowing through it.

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  8. #65
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    Quote Originally Posted by Homebrewblob View Post
    When I say pressurized I mean the feed line, I don’t plan to actually pressurize the bearing itself Per se.

    I just want to add a very low pressure feed to replace the lower oil feed wicks job.

    I would feel better if it can supply metered oil at a predictable rate.

    I also like the idea of this oil system PRE priming the spindle before starting to prevent dry starts.

    I think if I metered the oil and possibly enlarged the oil drain holes a bit (if possible) or even fitting large o-rings in the oil trenches as a barrier it could work.
    Sounds like you just need a pair of lunkenheimer oilers, one for each bearing.
    ~Vintage LUNKENHEIMER #1 1/2 Fig 1300 Sentinel Brass Oiler Hit and Miss Engine | eBay
    If your not familiar with these, the lever on top turns the flow on/off and the knurled section under the lever adjusts the flow, watch the drops in the small sightglass on the bottom.


    Or another option would be a madison kipp oiler, these pump the oil compared to gravity flow like the lunkenheimers. Oil volume is adjustable as well, sight glass on top to watch drops. Another nice thing on these is the hand crank to prime the system before start up. Here is a 2 feed one on epay:
    Madison Kipp model SV double lubricator | eBay

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  10. #66
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    Quote Originally Posted by Rob F. View Post
    Sounds like you just need a pair of lunkenheimer oilers, one for each bearing.
    ~Vintage LUNKENHEIMER #1 1/2 Fig 1300 Sentinel Brass Oiler Hit and Miss Engine | eBay
    If your not familiar with these, the lever on top turns the flow on/off and the knurled section under the lever adjusts the flow, watch the drops in the small sightglass on the bottom.


    Or another option would be a madison kipp oiler, these pump the oil compared to gravity flow like the lunkenheimers. Oil volume is adjustable as well, sight glass on top to watch drops. Another nice thing on these is the hand crank to prime the system before start up. Here is a 2 feed one on epay:
    Madison Kipp model SV double lubricator | eBay
    McMaster-Carr carry all this oily stuff in brand-new "vintage brass" as well.
    Easier to get the threads and such one wants from MMC than ePrey.

    Can even turn out to be cheaper, too!

    Agree gravity is the way to go, and "visible' is a nice plus.

    All the benefit an SB needs is "harder for Old Farts to forget to oil at all".

    "Old Farts" coming in all ages and genders, real or imaginary, as they tend to do..



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    Back to square ONE on the motor selection.

    Earlier today sent our OP an email wherein I had finally gotten a round tuit and dragged the alleged 2 HP T.B. Woods (by Baldor) DC motor mentioned early-on out from under the Herman surface plate stand.

    Sadly, it was only a ONE HP of a mere 3 ft/lb torque at full nameplate load!

    "Adequate" - if only barely - for the Burke #4 it had been purchased to run, but even the Burke has had a more powerful motor assigned.. so it needeth fewer mechanical ratios.

    1 HP is NOT adequate to run a SB 16" "usefully".


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    Quote Originally Posted by Homebrewblob View Post
    Does a vfd on a 3p motor allow constant speed under load?
    Yes. The phrase you are looking for is 'sensorless vector' and a drive that permits auto-tune with the motor coupled up to the spindle in the machine. VFD driven motors are constant torque below nameplate speed, and constant hp above nameplate speed. Example for me is an Hitachi drive running a 1.5 hp motor in a heavy 9 SB machine (think proto-10L) where the belt is kept in the middle speed sheaves all the time, and the spindle cannot be stopped even at tick-over, 2-3 rev/second. Control is a center-off toggle and a 1-turn speed control pot. Control box to on the LH side of the machine. I think this was an slower motor, you could optmize with a faster one if you wanted, 1725 or3600.
    Attached Thumbnails Attached Thumbnails jrr_h9.jpg  

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    I grew up in the 80's as a drives field service engineer. 90% of the work was DC. Today I work with motor repair shops on repair quality and motor reliability. I still get my fill of DC motors. I know my DC and AC motors, and I do considerable work on sizing motors, including replacing DC motors with AC motors/VFDs on a large scale.

    Not a chance in hell I would have a DC motor when I can have an AC motor with a VFD. Size the drive big enough and you can get breakaway torque out of the AC motor. Sensorless vector will perform to minimum speed just fine with rated torque.

    This ain't 1970 or 1980. In the early days of VFDs, they were run in v/hz mode and did suffer badly from low torque at low speeds. But that is no longer the case. Not if in sensorless vector and properly tuned.

  14. #70
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    Quote Originally Posted by markz528 View Post
    Not a chance in hell I would have a DC motor
    when they cost upwards of $12,000 USD, new ,and..

    when I can have an AC motor with a VFD.
    for one-tenth the spend.
    Size the drive big enough and you can get breakaway torque out of the AC motor.
    and it is cheaper even when you have to use an AC motor three times the rating of the DC motor.

    No need to rationalize.

    It was never your decision, was it? Employers and customers make those decisions.
    Can't fault them for taking the lower-cost route.

    Why would they not want to save the money if they could get by well-enough?

    I couldn't afford all these lovely "Type T" Reliance RPM III and vintage pre-"RPM" Type T DC motors EITHER.. if I had to buy them at NEW prices!

    ...instead of being grateful they were suplused by those chasing the cheap-seats option.

    Soooo...

    "Thank you for your ...... motors!"



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