New 440 only lathe needs step up xfmr
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    Default New 440 only lathe needs step up xfmr

    I recently got a new to me lathe (Nebel 1308) that is has a 440 only motor in it. I dont have much experience with step up transformers so am looking for a little guidance.
    I've been reading old posts about transformers and running them "backwards". It has been mentioned that the voltage might increase more than 2X when feed in the output. My voltage can be between 238-246 depending on POCO.
    Looking at step down from 480 to 120/208, 15 KVA and 480/240/120, 9 KVA. Seller thinks they are delta, but is away from them for a while. Should I go with a 480 to 240 knowing the 240 will be stepped up more than 480? If feeding 246v I imagine transformer getting really close to 500v output, seems to high to me but... If the xfmr does not have ability to change wires to tune the voltage should I just pass on them?
    The 3 phase for this would come from a 15hp RPC. Lathe has a 5hp motor. Here is a pic of them, will know more later today.
    2kva per motor hp would put me just about right with the 9kva unit. 3 or 4 hrs round trip drive to get it so would like to know as much as possible before a long drive...
    01515_jc72qusl3u0_600x450.jpg
    00j0j_8spmuvyuels_1200x900.jpg
    Last edited by Rob F.; 12-04-2019 at 03:40 PM. Reason: add second pic

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    Quote Originally Posted by Rob F. View Post
    I recently got a new to me lathe (Nebel 1308) that is has a 440 only motor in it.
    Been reading about transformers and running them "backwards". It has been mentioned that the voltage might increase more than 2X when feed in the output. My voltage can be between 238-246 depending on POCO.
    Looking at step down from 480 to 120/208, 15 KVA and 480/240/120, 9 KVA. Seller thinks they are delta, but is away from them for a while. Should I go with a 480 to 240 knowing the 240 will be stepped up more than 480? If feeding 246v I imagine transformer getting really close to 500v output, seems to high to me but... If the xfmr does not have ability to change wires to tune the voltage should I just pass on them?
    The 3 phase for this would come from a 15hp RPC. Lathe has a 5hp motor. Here is a pic of them, will know more later today.
    Unless you can actually TEST the delivered voltages, you prolly don't want to run a "Wye" wound backwards (208/416 one side practically shouts "Wye") nor hope the actuals come out where expected off the back of extrapolating the maths. Cost of Buck/Boost added to - usually 2 legs - of 3-Phase eats up any savings.

    Delta-Delta with (usually 10%) adjusting taps would be more predictably useful.

    I have a 15 KVA one surplus, but shipping would eat both our lunches.

    R.E. Uptegraff elliptical coil, all Copper, so just under 400 lbs, Avoir, mebbe half again the usual size and mass. Uptegraff could get a tad OCD about longer-life than average. Elliptical rather than rounded-corner rectangular bobbins were a part of that - there is a "white paper" on it.

    Folks think of a transformer as a device with no moving or wearing parts.

    T'aint so.

    Not only do the laminations rub against each other, the winding wire is squeezed and released in diameter, lengthened and shortened, long-axis, every cycle from birth until-Hell-freezes-over day. Utility/Powerco want no LESS than a 20 year life, usually get twice that or more before insulation succumbs.

    An Uptegraff Eliptical might go a hundred years. Not sure anyone yet knows. Let-alone has to CARE.

    R. E. Uptegraff Manufacturing Co.

    My next-best favourite, and good value-for-money, is EGS/Hevi-Duty, but they ALL "work" NEMA. NEC. UL. CE. etc. etc. No place to hide. They HAD to do.

    NB: A good many of the transformers settin' used were pulled for both age AND for mandated efficiency improvements, and/or recognition that what HAD been 220, then 230, had become 240. And a bit.

    245 VAC utility mains have been reported from many among us, and off GOOD and reliably accurate DVM's, not cheap junk.

    The lathe motor isn't really as picky as all that, but still - adjusting taps beat having to also find a pair of buck/boost.

    I'd check eBay. THEN the seller locations. There is usually at least one major recycler serving anything as even resembles the major population centers, just not usually within it. Space and taxation cost thing.

    Even so, should be a major within a one-day out and back "go fetch" as has decent goods, MORE choices than published and not not junk. Kalifornikyah SSR rezi-dents will know whom and where arredy.

    Such outfits typically list 10% or less of what they have in their hands on eBay. They expect yah to contact them and ASK.

    HTH

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    I think you have it reversed. A transformer should be wound to compensate for losses in the transformer. When reversed, the compensation would be reversed and now you would have the losses in the transformer plus the compensation (turns ratio) of the windings both acting to reduce the voltage.

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    Motor voltage ratings are always +-10% minimum, so if the motor is rated for 440V, it is fine with up to 484V. Once you exceed that, the motor "saturates" and heats up disproportionately to the applied load. If the applied load is nowhere near the maximum rating, you may never ever know the difference. I think that you would have to be doing some REALLY SERIOUS turning to get a 5HP motor to full load on a lathe.

    I suggest using the 9kVA 240-480V transformer. Yes, it will be Delta, but that is totally irrelevant. It also is likely to have "taps", used to adjust voltages, i.e. you will see something on the nameplate that says "2 x 2-1.2% FCBN" or words to that effect. That means there are two taps at 2-1/2% of the voltage capable of "Full Capacity Below Normal", so you can connect to those taps to drop the voltage change ratio by up to 5% in two stages.

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    Quote Originally Posted by Bill Simmons View Post
    I think you have it reversed. A transformer should be wound to compensate for losses in the transformer. When reversed, the compensation would be reversed and now you would have the losses in the transformer plus the compensation (turns ratio) of the windings both acting to reduce the voltage.
    Which means the net-net off 245 in rather than 220 or 230 MIGHT hit the sweet spot, but.. I did say "if you can MEASURE" it for less risk.

    OR.. it is one some other Pilgrim has the same maker and SKU number of...

    Long and short of it is that the buggers make rather clumsy and hard to get rid of "pets" if yah get one yah cannot JF USE, and "directly so".

    DAMHIKT

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    I suggest staying away from the 208V secondary units. Standard transformers don't have any adjustment on the secondary side (208), If you feed a 208 rated coil with 245V continuously, it will likely saturate and run very hot.

    Using the 240V secondary model, keeps you away from saturation at 245V input. Then you can adjust the takeoff voltage from the high side taps, which are customary on most units.

    SAF Ω

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    Quote Originally Posted by Rob F. View Post
    I recently got a new to me lathe (Nebel 1308) that is has a 440 only motor in it. I dont have much experience with step up transformers so am looking for a little guidance.
    I've been reading old posts about transformers and running them "backwards". It has been mentioned that the voltage might increase more than 2X when feed in the output. My voltage can be between 238-246 depending on POCO.
    Looking at step down from 480 to 120/208, 15 KVA and 480/240/120, 9 KVA. Seller thinks they are delta, but is away from them for a while. Should I go with a 480 to 240 knowing the 240 will be stepped up more than 480? If feeding 246v I imagine transformer getting really close to 500v output, seems to high to me but... If the xfmr does not have ability to change wires to tune the voltage should I just pass on them?
    The 3 phase for this would come from a 15hp RPC. Lathe has a 5hp motor. Here is a pic of them, will know more later today.
    2kva per motor hp would put me just about right with the 9kva unit. 3 or 4 hrs round trip drive to get it so would like to know as much as possible before a long drive...
    01515_jc72qusl3u0_600x450.jpg
    00j0j_8spmuvyuels_1200x900.jpg
    You should double check that the motor is 440 only. That would be unusual. Pop the cover on the motor, if you have 12 wires, it is 208 or 440. This would allow you to wire the field coils in parallel or series.

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    Quote Originally Posted by steve-l View Post
    You should double check that the motor is 440 only. That would be unusual. Pop the cover on the motor, if you have 12 wires, it is 208 or 440. This would allow you to wire the field coils in parallel or series.
    Seconded. Or dare I say "repeated"? If the JHolland/Halcohead Nebel was made to work on 2XX, yours should be much the same.

    Not machines as common as most others. Probably not many variations. Transformer cost, go-fetch, space, nuisance, heat, noise, and wasted coin can be avoided, even a third-party motor-shop reconfigure at a premium can be far the better investment, long-term.

    That's why my Uptegraff 15 KVA became surplus.

    Three motors & c. out of four on the Quartet combo mill to re-terminate, swap heaters, juice pump simply shitcanned for a 1-Phase. One motor on the Alzmetall, same again 1-P juicer.

    PITA, but needed to be done exactly ONCE, then never again.

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    Quote Originally Posted by steve-l View Post
    You should double check that the motor is 440 only. That would be unusual. Pop the cover on the motor, if you have 12 wires, it is 208 or 440. This would allow you to wire the field coils in parallel or series.
    Quote Originally Posted by thermite View Post
    Seconded. Or dare I say "repeated"? If the JHolland/Halcohead Nebel was made to work on 2XX, yours should be much the same.
    I completely agree. I looked in the peckerhead to see ONLY 3 wires coming out of the body of the motor. But, I also have not been able to read the motor tag yet to confirm possible voltages. Maybe try later today, time permitting.

    If I have to I don't mind using the transformer. I also have a 3 hp 440 wired drill press not in use now. I know that can be swapped to 240 use & that is/was the plan but with xfmr no need to mess with it.

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    Quote Originally Posted by Rob F. View Post
    I completely agree. I looked in the peckerhead to see ONLY 3 wires coming out of the body of the motor. But, I also have not been able to read the motor tag yet to confirm possible voltages. Maybe try later today, time permitting.

    If I have to I don't mind using the transformer. I also have a 3 hp 440 wired drill press not in use now. I know that can be swapped to 240 use & that is/was the plan but with xfmr no need to mess with it.
    If you have only 3 wires, it is a single phase motor. If so, throw the motor away and start over........it's much less expensive.

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    Quote Originally Posted by steve-l View Post
    If you have only 3 wires, it is a single phase motor. If so, throw the motor away and start over........it's much less expensive.
    3 ph 440 or "maybe" 220/440.
    From nebel thread, post 13:
    Quote Originally Posted by Rob F. View Post
    The motor is a pancake looking thing that is integral to the Cleveland Variator "gearbox". Looks to about 16" in dia and about 8" long. drive motor/gearbox is installed under the headstock with the motor end in first. It is very tight in there so a motor change would be a fair bit of work. Gearbox is rated for 5hp so is likely a 5hp motor, 3hp was also provided on these. Could not read the tag, it is facing straight up with 1" space or so above it, under headstock floor. Some mirrors and bright lights may help...
    Thread:
    Need a Nebel 1308 microturn toolroom late for <$1K?

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    This is the used transformer I am looking at.
    HPS model# SG3A0015DK
    SG3A0015DK | Hammond Power | Transformers

    Aluminum wound, is that a problem?

    The guy also had 9kva xfmr's but were 208 to 480.
    Just need to get a look at the motor tag before going to get this.

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    Quote Originally Posted by Rob F. View Post
    This is the used transformer I am looking at.
    HPS model# SG3A0015DK
    SG3A0015DK | Hammond Power | Transformers

    Aluminum wound, is that a problem?

    The guy also had 9kva xfmr's but were 208 to 480.
    Just need to get a look at the motor tag before going to get this.
    Hammond are capable folk. They "do" shiney-wood wound OK.
    I won't go near 'loominum for that, but that's just "me".

    Conductivity and reliable terminations, they compensate for just fine.

    MOVEMENT, off the back of thermals? Not so easy. Laws of physics and such.

    Copper windings live longer.

    New, yah gets a ten-year warranty on 'loominum. Buying used 'loominum goods?

    Well.. they are cheaper of the back of scary value of Copper.

    But you might be lookin' at a 'loominum unit already twenty years into that ten year warranty.

    Copper is simply lower risk, used goods no longer new are in the game.


    You REALLY DO need to slow TF down. This is not an emergency.

    Get an eyeball on that motor.

    Gar-ron-tee it has more than three leads back of the hole to the Peckerhead.

    Motor shop it for a look at possible re-term if yah hafta. If you can avoid twenty-year of transformer nuisance noise, wasted space, and for-fee power wasted if re-terminated to 2XX VAC - same as the JHOLLAND/Halcohead one already proves is possible?

    Well worth taking yer time.
    Last edited by thermite; 12-05-2019 at 11:35 PM.

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    Default Sg3a0015dk

    Quote Originally Posted by Rob F. View Post
    This is the used transformer I am looking at.
    HPS model# SG3A0015DK
    SG3A0015DK | Hammond Power | Transformers

    Aluminum wound, is that a problem?

    The guy also had 9kva xfmr's but were 208 to 480.
    Just need to get a look at the motor tag before going to get this.
    That number, SG3A0015DK appears to be the proper unit, I would want to see the tag to be sure, Proper step up, (not step down, used in reverse) 15KVA 240V delta input and 480 wye output. Aluminum is standard material for Hammond. Wye output so it can be a grounded 480V output.

    hps-catalog-cht.jpg

    hps-selection-guide.jpg

    conndiag.jpg

    I looked in the peckerhead to see ONLY 3 wires coming out of the body of the motor. But, I also have not been able to read the motor tag yet to confirm possible voltages. Maybe try later today, time permitting.
    A 480V motor, with just three leads exiting the stator housing , not the conduit leaving the head, would indicate to me that its likely been rewound, and they only brought out the leads needed for a 480V connection. If your talking about wires leaving the connection head, three is the standard for any voltage.

    SAF Ω

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    I think the best to do is get the transformer. I will double check its tag in person to be sure it is what I was told. This will get the machine running with minimal expense of time & money. I would like to verify the rest of the machine is in good working order before getting to deep into anything. (I did buy it not under power)
    Yes, there are just the 3 leads out of the stator housing, into the peckerhead. I will reach into the hole they come from and feel around for more wires that could be tucked back inside, but there was no hint of that when I looked in there the other day. Still need an eyeball on the tag.

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    Quote Originally Posted by Rob F. View Post
    I think the best to do is get the transformer. I will double check its tag in person to be sure it is what I was told. This will get the machine running with minimal expense of time & money. I would like to verify the rest of the machine is in good working order before getting to deep into anything. (I did buy it not under power)
    Yes, there are just the 3 leads out of the stator housing, into the peckerhead. I will reach into the hole they come from and feel around for more wires that could be tucked back inside, but there was no hint of that when I looked in there the other day. Still need an eyeball on the tag.
    IF, as SAF suspects.. it had a long-ago rewind, simpler and cheaper 440 only, the tag may now be a lie. Good shop adds one of their own, so-sayin' as to wot they had done, and dated.

    But they ain't usually as durable nor always as well attached.

    Should be a production date on that Hammond, you get to eyes-on range.
    Take the age onboard, any 'loominum goods especially.

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    IF it a 440 only motor, can it be "easily" made to be dual voltage by adding in the additional wires, or would that mean a complete rewind. Long term I would like to not have to use a transformer... Nice surprise that it is a proper step up one though (not how it was advertised)

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    Nothing easy about re-leading for dual voltage, almost as much work as a rewind, cost's likely near the same.

    If it's in good condition, you must cut the stator lacing apart to un-bury the connections. Then break the connections apart, clean conductors of varnish, and re-braze a new lead set on and insulate them all. Tie the splices back down to the stator winding's with lacing, then varnish and bake. Reassemble and test.

    The process is just a few less steps than a complete burnout and rewind, and can sometimes can be problematic, depending on condition and the quality of the last job. The shop I use, usually wants to do the whole deal to warranty it.

    The tag is likely to be modified if rewound for a single voltage, usually XX out the data for the voltage no longer used.

    Then you would need to consider the controls for the voltage change. Half the voltage, requires twice the current, can the existing controls handle that? Many older machines could, they were built to be field convertible, but you would likely require larger heater elements at a minimum, for the motor starter.

    SAF Ω

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    Motor has definatly been rewound 440 only, the motor leads are very soft and pliable, with a slight rubbery feel to them. Like leads in a brand new motor feel like. Not what would be in a 60yrs or so machine. But the proof was just as SAF said, in the tag. 220 has been scratched off. It did confirm 5hp. Camera and mirror got the tag.
    Sorry for the "mirror image of the motor tag, I couldnt figure out how to flip it... frame: 2541, type: PJX HP: 5, RPM: 1750.
    p1070434.jpgp1070436.jpgp1070437.jpgp1070438.jpg
    Pic with tape is showing the 6" length of motor, I also got one of the tag on the Cleveland Variator the motor is coupled to.

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    Quote Originally Posted by Rob F. View Post
    Motor has definatly been rewound 440 only, the motor leads are very soft and pliable, with a slight rubbery feel to them. Like leads in a brand new motor feel like. Not what would be in a 60yrs or so machine.
    Depends on what they paid-for. 1942 10EE wiring was as good as new.

    But yah. It would take motor shop work to put it back to 240 or selectable.

    Might want to do that "someday, maybe", but until you sort how good - or not - and how useful - or not - the overall machine is?

    You might sell-it-on before the year is out, so the transformer is the easier choice.

    Cleveland Gear website still has the docs on their Variators:

    Literature & Catalogs - Cleveland Gear Company


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