Intermittent starting problem 1945 10EE MG - Page 3
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  1. #41
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    Quote Originally Posted by lectrician1 View Post
    there was a piece of thin rope that flew off the armature that was causing the sparking. it was the rope or twine that is wrapped around the armature and varnished to hold everything in place. The outer wraps of rope on my spindle motor are coming off.

    i removed and inspected all the brushes yesterday. cleaned any debris. all brushes looked good. about an inch long. i didn't time them.
    retaining springs where good. everything seemed tight. no more sparking


    i just ordered six new capacitors for my RPC
    AFAIK that is genuine linen cord. From stalks of the flax plant. The one as also gives is linseed oil. Age of the motor thing. Cheap, cheerful, did the job, lasted a long time when waxed or varnished.

    We still used it AGES later to lace cable bundles, telco industry for neat and tidy. Then came nylon and auto-feed tie-wrap "guns".

    If it is coming off? Two things likely. Uber-high RPM the least likely, actually. Though I have had it happen, that motor was under deliberate stress-test few have the power available to force and fewer-yet would WANT to even attempt.

    Age, plus chemicals, solvents, and/or biological degradation far more probable.

    It needs seen-to, either way if the motor is to NOT continue to degrade.

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    Quote Originally Posted by lectrician1 View Post
    Attachment 270020

    here is another try at posting the pic
    The original maker happens to still-yet-today sell the ceramic forms that they - and others - wind new ones onto.

    The wire is still a commodity item as well.

    That said, Toroids - 'coz that is wot the "class" of the shape is - are the very devil to wind smoothly "by hand". Machines that do it well resemble spiders on drugs copulating .. Or something like that. Gave that class a miss at school. Girls were challenge enough.

    One or more among us may even HAVE such a rig?

    Annnd there ARE used-but-not-abused ones 'out there' as leftovers from either of DC Drive or VFD conversions, neither of which can (or SHOULD) use them.

    Wrong resistance values, even if the size is tolerable.

    "Meanwhile".. go off to the outer edge, where the slider does not touch.

    Scrape the ends, close to the bad spot. Solder or Sil-Flo a SHORT bridge across the gap. It need not be "resistance" wire. Nickel-Chromium alloys, mostly, see "Nichrome". Easier to solder if it is NOT, actually.

    Now about the arc... you ALSO need a conductive bridge the slider can smoothly traverse, up in its wear-track. That is harder.

    Silver solder or Sil-Flo might git 'er done? Keep in mind our outer-edge repair was to educe the potential across the top-side gap for lower stress.

    Some other Pilgrim will surely have better advice on that part?

    Once done, you'll have a flat spot, RPM-adjustment-wise, but not MUCH of one. And it will work OK until you can find another rheostat in better condition.

  3. #43
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    i believe the intermittent starting problem has been solved.
    there were broken wires on my variable speed rheostat
    exactly where the generator would go into failure/bogging condition
    the breaks were in the contact area and there was serious arcing going on there
    I soldered a jumper across the bad section of the rheostat. It works great
    No more bogging
    Starts at all speeds, back gear, and under load
    thanks all for your assistance

    dont hesitate to contact me if you have the same issue

  4. #44
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    What exactly do you mean by "generator bogging"? Was the motor/generator actually slowing down, or was the spindle just not coming up to speed?

    Cal

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    check video on youtube listen to the gen bogging especially when i flip the drum switch to off. you can hear the motor generator speed up

    YouTube

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    Woo not sure what to think about that. If I ever heard a bog down that would be it. Something is loading the the motor supplying energy to the two generators. Beyond that there are mechanical load issues on the spindle motor or current draining issues on the spindle motor (short?).


    Quote Originally Posted by lectrician1 View Post
    check video on youtube listen to the gen bogging especially when i flip the drum switch to off. you can hear the motor generator speed up

    YouTube

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    the arcing in the rheostat was causing the bogging . all fixed now. that was a video from last week

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    OK. I can see how the break in the rheostat would cause the spindle to have problems coming up to speed. Once the rheostat hits the open spot, the spindle motor looses field and may not have enough torque to come up to speed. But I DO NOT see how that can cause such a load on the generator that it will slow down. Unfortunately, you didn't make the current readings that I asked for, so figuring out what the chain of events was remains a mystery.

    So until someone explains exactly how this works, I'm gonna go out on a limb and say, no, the arcing in the rheostat didn't directly cause the motor/generator to slow down.

    Cal

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    Quote Originally Posted by lectrician1 View Post
    the arcing in the rheostat was causing the bogging . all fixed now. that was a video from last week
    Not sure it is "all" fixed, yet.

    The symptom last week was bass-ackwards.

    Both rheostats are in series, current-limiting the flow to Field coils, as force-multipliers.

    - WHEN.. you had an "open" the slider was arcing whilst trying to bridge..

    - THEN positioned one side of the gap, there would be no flow.

    - IF that was the Rheostat for the Field of the primary DC generator (MG),

    - THEN a weaker field - just remanence only - would drop the Generator output Voltage, starving the final-drive motor Armature,

    - BUT.. UNloading the AC motor, not bogging it down, because it was driving a nearly unloaded DC generator.

    OTOH:

    - IF the "open" Rheostat were the one feeding the final-drive motor's field, an open would starve the Field. As a motor, not generator, it would have low/no torque.

    So.. if "bogging down", or not starting smartly, it should have been the final-drive motor exhibiting that, not the MG section.

    At all.

    What have I missed?

    AND... whilst now continuously-variable again and smooth.. Is it operating the final-drive motor at full torque?

    We'e seen this movie before. Beel/BICL drives unboosted, 180 VDC drives as CANNOT take boost. These only hit top RPM under low/no load. Or just never.

    How STRONGLY is your 10EE actually PULLING?

    I don't trust that lab-bench Field supply any further than I can trust Bull Schiff.

    Foldback current limiting happen to be in that PSU's DNA?

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    I dont have an ax to grind. I am not trying to prove anything.
    I had a problem(generator bogging and wouldn't start spindle motor).
    I asked for some help with that problem
    I appreciate your help
    I found something wrong with one of the components in my system(the rheostat in series with the spindle
    motor field)
    I did my best to repair the component
    I reinstalled the component and the problem seems to have gone away.

    That is all.

  11. #51
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    What you have found, will result in a field loss, when starting with no field, will overload the MG.
    Operating the FA relay, will bypass the motor field rheostat, providing full field to the motor.
    I had problems with my first EE, one wire to the field would come open after 5-10 min at full field.
    This is why it is important to measure the motor field at the motor, while you are having the problem!
    Apparently, this was never done, allowing the rabbit trails to consume the troubleshooting.
    Bill

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    Quote Originally Posted by hitandmiss View Post
    What you have found, will result in a field loss, when starting with no field, will overload the MG.
    Operating the FA relay, will bypass the motor field rheostat, providing full field to the motor.
    I had problems with my first EE, one wire to the field would come open after 5-10 min at full field.
    This is why it is important to measure the motor field at the motor, while you are having the problem!
    Apparently, this was never done, allowing the rabbit trails to consume the troubleshooting.
    Bill
    Thanks. Learned something new just now.

    HOW can it be "new"?

    In all my testing of the large-frame (and small frame) 10EE motors I was not USING the MG to power them.

    By accident of scrapping two vehicles with nearly-new batteries - which I retained - initial test let me put 24 VDC off batteries meant for starting IC engines. No field, motors turned over slow, but there was no "bog down"!

    Next up, the (Eurotherm)/Parker-SSD DC Drives. Optioned for their full 16A, set to allow 150% overload for 90 seconds. They didn't give a damn, either.

    Until just now, I did not KNOW an MG could "bog down" for lack of a powered Field. Shame on me. But it is a now wiser "me", so I call it a good day.

    As to the earlier suggestion that Voltages be measured AT the motor?

    I, too, stand firm on that one.

    ANY fault "upstream" of it, be it failed source, failed control component, or simply a wire or termination perhaps 70 or more years in service breaks? The motor peckerhead is close to the "last place that matters".

    "Close to", because, lest we forget, ancient leads INSIDE a motor fail, too, now and then.



    ALso, lest we forget, the fault was ultimately FOUND by a "dumb-old farm-boy" trick that didn't even need a common Voltmeter. Mark One human eyeball, rather.

    Turning out the lights and working in the dark.

    For real. Not just on the internet!



    Cooperative effort, stone soup parties are, Brethren. Many hands. Many eyes. Many similar - and DIFFERENT - background experiences.

    Everybody brings what they can. Keep an open mind. All gain. No one has to go away hungry.

    Nor go away pissed-off, either, yah?

    Any day yah learn something new is a good day...

    PM at work. Doing what PM does best.

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    in this case,the problem with testing voltages and amperages at different locations, was that the bogging condition was INTERMITTENT. The lathe would operate correctly 20 starts in a row then it would go into failure 15 starts in a row, then for no apparent reason, it would start working again. The break in the rheostat wire wrap was in the contact area. So i guess sometimes the contact would push the wire close enough together that it would operate correctly for a day or two. Maybe it was moisture in the air IDK. I was hoping that the failure condition would remain constant so could find it. I did open the peckerhead and measure voltages at some point. The bogging was coming from the MG, so it could have been the MG motor problem, or the generator was at fault, or the spindle motor was at fault, or an RPC problem, or a problem with service voltage. Keep in mind that I also replaced the broken exciter with a DC power supply, so that could've been the issue. Also the FA relay was not working, so that could be the problem. I had 3 voltmeters measure voltage drop on all three phases from different locations. Then all of a sudden, for no apparent reason, the machine would start working properly again. Then there is no chance of finding a problem that doesnt exist.
    Finally towards the end, the problem got so bad that the machine went into constant failure mode. I was glad to see that because then I was able to sort it out. All in all the whole process took about a week or ten days or so. Thanks to the great help of the PM members.

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    Time will tell if the DC power supply is a reliable fix for a non working exciter.
    The machine seems to be working flawlessly with the DC power supply at 120v DC 3 amp capacity. The amp draw never exceeds 2.1a according to the meter on front of unit.
    The power supply was $96 shipped from ebay. Chinese with 2yr warranty IIRC.

    The power supply operates on 220V single phase AC which I picked up at the T1 and T2 terminals in the MG terminal box located in the center cavity of the lathe
    The DC output of the power supply went to terminals E2 and E1 in the MG terminal box. A small note on the schematic states that polarity matters for a correctly operating FA relay.
    Positive went to E2 . Negative went to E1.
    Although I followed the directions on the schematic, my FA relay does not seem to function.
    Probably bad relay. I tried polarity both ways.

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    Quote Originally Posted by lectrician1 View Post
    The amp draw never exceeds 2.1a according to the meter on front of unit.
    Useful, if not new, "seldom seen" figures.

    The load the final-drive motor uses for its field is on the data plate, 1.4A is it?
    Not sure if the ration used in the MG is data-plated as well. ISTR those plates aren't easily seen unless the MG is pulled out.

    The rest of the ration is holding-in relay coils (de minimus) or a contactor (more significant, but not large).

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    Quote Originally Posted by lectrician1 View Post
    there was a piece of thin rope that flew off the armature that was causing the sparking. it was the rope or twine that is wrapped around the armature and varnished to hold everything in place. The outer wraps of rope on my spindle motor are coming off.
    So based on the problem you are having, I suspect that the PO had employees running the lathe
    and occasionally when increasing speed with the spindle running, there would be a field loss and the motor would start to run away.
    Probably no one would use that lathe, or the maint dept. couldn't fix it, so it was sold off.

    The "thin rope" coming off are an indication of way overspeed. My first EE that would loose the field a few min after starting, the motor would be turning over 4000 RPM using a good tach and only have 20 Volts on the armature, along with excessive sparking at the brushes.

    My second EE with the inline exciter has an FA relay that never operates. The series field on the generator is not connected either. It works fine, I am of the mindset if it ain't broke, don't "fix" it.

    Bill

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    Quote Originally Posted by hitandmiss View Post
    So based on the problem you are having, I suspect that the PO had employees running the lathe
    and occasionally when increasing speed with the spindle running, there would be a field loss and the motor would start to run away.
    Probably no one would use that lathe, or the maint dept. couldn't fix it, so it was sold off.
    Seconded. If not already suspected and mentioned. This fits very well with the already-deteriorating condition of the cord.
    My first EE that would loose the field a few min after starting, the motor would be turning over 4000 RPM using a good tach and only have 20 Volts on the armature, along with excessive sparking at the brushes.
    That first "few minutes" could even have been well-under a full minute to have magnetized the Iron as much as it will or will not retain magnetism anyway. It isn't meant to, actually.

    By comparison, the motor I chose for (potentially) destructive testing was from a part-out. It had sat for AT LEAST a full year, perhaps more than three years, not having had any power to it at all.

    Even so.. with no load, not even a gearbox, it would creep along off auto batteries, run right about the normal RPM band, proper Armature supply, only - no Field power at all.

    No TORQUE to that, weak as the remanence had degraded to - one could stop the shaft by hand.

    Do NOT "try that at home!" with proper power to Field and Armature!

    You are odds-on to lose the hand, get turnt into a pretzel, or be flung over into the corner, rag-doll style. Dinosaur Current shunt-wounders are torque animals. Can't slip.

    Move the load, trip a protective device, or die trying.

    Yah don't see a lot of dead ones, so best to not mess.

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    previous owner did quite a bit of work on the machine. all the wires to spindle motor peckerheaed were changed, the wires to the bottom of the DC panel changed, wires from the dc panel to the MG terminal box changed, there were wires added to the non working exciter, then there was a home made dc power supply with a transformer, rectifier and some caps, that supplied 85vdc that the machine was running on when i first started it. there was also a large buck and boost transformer on the back of the machine which might have been for the 440v coil on the mag starter. Wires to the drum switch and the start/stop switch all been changed.
    previous owner also graciously installed grease in almost every orifice, even the ones with the cap that says OIL! there was grease in the apron, grease in the back gear, grease in the headstock, grease everywhere. FUN FUN

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    Quote Originally Posted by lectrician1 View Post
    previous owner did quite a bit of work on the machine. all the wires to spindle motor peckerheaed were changed, the wires to the bottom of the DC panel changed, wires from the dc panel to the MG terminal box changed, there were wires added to the non working exciter, then there was a home made dc power supply with a transformer, rectifier and some caps, that supplied 85vdc that the machine was running on when i first started it. there was also a large buck and boost transformer on the back of the machine which might have been for the 440v coil on the mag starter. Wires to the drum switch and the start/stop switch all been changed.
    previous owner also graciously installed grease in almost every orifice, even the ones with the cap that says OIL! there was grease in the apron, grease in the back gear, grease in the headstock, grease everywhere. FUN FUN
    LOL! We were about due for a good laugh! Maybe we can even have a BEVERAGE now?

    At least it wasn't K-Y Jelly.... or "Boy butter"!

    Or WAS it?

    Don't answer that... someone will want to know how you know the difference..



    PS: Do you still HAVE the exciter? The piggyback ones may not be all that hard to put back right.

    And then you'd have their contribution to compensation/stability the fixed PSU cannot help with.

    Reliance migrated Monarch to that awkward-looking ugly-ducking rig off the inline exciter for good reasons.

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    i have the exciter. what do i do with it?


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