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  • Almond farmer
    started a topic Thunderbolt & Thunderbolt XL transformers

    Thunderbolt & Thunderbolt XL transformers

    Does the Thunderbolt 225AC\150DC with top mounted shunt crank current adjustment use aluminum or copper in the primary\secondary transformer windings and the inductor choke?
    Same question for the Thunderbolt XL ,later model, with front mounted shut crank.

    Understand aluminum has 50% more resistance than copper, which means the transformer would generate more heat with AL with equal current on secondary for both AL & Cu.

  • Helios
    replied
    This sounds like a serious case of "a little bit of knowledge is a dangerous thing."

    Leave a comment:


  • MAC702
    replied
    Yep.

    Welding machines have no need for the neutral conductor, just the two hots. Plus the ground and they just need a 3-prong plug.

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  • Almond farmer
    replied
    Forney 235AC\DC transformer/choke unit uses covered insulation stranded aluminium wire for primary, secondary transformer windings and choke windings using white colored insulation.

    so what is the best solution for the front lead terminal connection where the electrical path is aluminum to threaded nut to brass connector?

    Welding machines that live in the desert do not have the corrosion issues that welding machines that live on the coast or rainy demographics like Oregon.

    Will pull the panel tomorrow, since need to install 50 amp 220 VAC nema 6-50r receptacle.
    Would guess underground feed line is AL.

    All the breaker slots should be Cu-Al plated alloy to accept aluminum or copper wire.
    Are metal connections on the breakers Cu-Al?
    Noticed the metal mounting plate on the flush mount Levetron 6-50r receptacle is stamped Cu-Al

    Need to find coated 1/2"-20 Cu-Al nuts to fit the brass lead terminals, maybe the best solution...good luck with that

    Have noticed the 220 VAC welders are three prong rather than four prong.

    Leave a comment:


  • MAC702
    replied
    Thank you for looking up residential use of aluminium wiring and correcting your previous statements. But still not showing any related failures in the scope of the thread. Chances are, the electrical panel in your house is full of aluminum to copper connections. It's been known for over fifty years now how to do it properly and safely.

    Are you saying there is even one person out there who opened up their welding machine, saw red-shellac on aluminum and said, "Cool! My machine is copper!" Do you think a person that would do so is actually a person that knows the differences?

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  • Almond farmer
    replied

    I know the red colored coating is shellac and used as an insulator on transformer windings and electric motor field windings.
    however , looking from a distance it might appear that your aluminum transformer windings are copper,since the red colored shellac is almost the same color a corroded copper conductor.

    when subjected to vibration the hard shellac, can wear off and decrease the number of affective core windings.
    This condition happens to motors, still rotate at specified speed, but rated torque is reduced.
    The large welder transformer vibrates from eddy currents.

    Is most if not all overhead and underground feed lines to houses, apartments, condos from utility company (residential not commercial) 8000 series AL?

    if aluminum wiring is still used in residual it must be a minimum 8 gage strained from the best able to determine and 8000 series even for a 15 amp circuit.

    The point is residual in the 60's and early seventies when aluminum solid wire was used and copper wire price was quite high the issues were with the connections, aluminum to copper switches, fixtures, etc., Failures occurred at the connections.

    aluminum transformer based welders have the same issue at the copper/brass to aluminum connections.

    The GE paper linked by Aero addresses two basic issues with All to Cu connections.
    1. Connection loosening
    2. Corrosion

    loosening
    when the Al transfers current with resulting generated heat the Al flat strap and square cross section want to expand , but limited by the thermal expansion of the brass stud. So the Al is plastically permanently deformed past yield. Then when the Al cools with current removed the Al has some degree of spring back but the thickness has decreased. Each time the cycle is repeated the Al gets thinner.
    experienced a loose connection on the Thunderbolt AC negative terminal.
    however the brass stud has a thermal expansion coefficient = ~ 11.3 micro in /in, if yellow brass
    while 1100 AL has a thermal expansion coefficient = ~13.1 micro in in, which is better than if the stud was steel at ~6.5 micro in in.

    On corrosion , the paper states that bare All should not be mated to bare brass or Cu because of galvanic action.
    It states the AL and Cu should be tin coated
    when wiring custom motor cycles and farm tractors have always used tinned stranded copper wire, tinned copper lugs, tin copper buses bars.
    thunderbolt connections are between bare Al & bare Cu causing a corrosion issue

    ​​​​​​​really do not yet have a solution.
    Last edited by Almond farmer; 12-14-2017, 12:14 AM.

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  • MAC702
    replied
    Originally posted by Almond farmer View Post
    ...The AL windings are coated with a red colored shellac giving the appearance of copper.

    mac702
    do not know where to find residential AL wire.
    Some counties adopt the national electrical code , some counties have there own electrical code.
    Some cities adopt the national electrical code, some cities have there own electrical code.
    Los Angeles city has there own electrical code.

    These transformer based welding machines have the same corrosion issues,
    brass lead thermal stud to AL conductor connections with increased electrical resistance from galvanic corrosion.
    That shellac is the insulation. That same red shellac is used on copper windings, too. Are you insinuating a nefarious purpose here?

    Local codes are not relevant. You specifically called out the NEC and gave a misleading reason for a total residential ban that does not exist. Since you're new here, I'll remind the record that I've been an electrician for two decades.

    So there are more welding machine failures now? And they've been attributed to aluminum? Sounds like a good time for a source.

    BTW, the 2017 City of Los Angeles Electrical Code is based on the 2016 California Electrical Code and the 2014 NEC. They don't start from scratch. Feel free to discuss specific amendments, with citations.
    Last edited by MAC702; 12-13-2017, 11:51 AM.

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  • Almond farmer
    replied
    Answering my own question.
    Yes the 1993-1995 Thunderbolt 225 AC & Thunderbolt 225 AC/150 DC has aluminum(AL) primary & secondary transformer windings and aluminum choke windings on the DC unit verified by cover removal.
    The AL windings are coated with a red colored shellac giving the appearance of copper.

    mac702
    do not know where to find residential AL wire.
    Some counties adopt the national electrical code , some counties have there own electrical code.
    Some cities adopt the national electrical code, some cities have there own electrical code.
    Los Angeles city has there own electrical code.

    These transformer based welding machines have the same corrosion issues,
    brass lead thermal stud to AL conductor connections with increased electrical resistance from galvanic corrosion.

    Leave a comment:


  • ryanjones2150
    replied
    I don't know about you guys, buy my old thunderbolt transformers are wound with steady and reliable somethingorother and I like it.

    Leave a comment:


  • MAC702
    replied
    Originally posted by Almond farmer View Post
    The machine was probably reengineered to reduce cost.
    Prefer the older design over the new XL design.

    Al was used for residential house wiring until some fires occured because of extra resistance from corroded aluminum oxide at connections.
    The national electrical code eliminated aluminum material house wiring.
    Difficult find or make an aluminum extension cord. Welding leads are all Cu.
    Found a commercial DC welder choke made from soft copper tubing on a straight ferrite round core.
    Lower cost is not a bad reason in and of itself. Some might think it's a good reason. Lighter machine is preferable to some as well.

    Actual performance issues seem to be missing from the comparison.

    Problems with aluminum wiring in residential was from termination methods needing to be different, not from problems difficult to fix. Aluminum wire is still allowed on larger circuits in new residential, and proper devices for existing aluminum wiring on the smaller circuits are easily acquired. You really need to cite sources when you make these claims. That will help you see that they are false before you post it publicly.

    Extension cords and welding leads need the flexible durability of copper. This has nothing to do with conductivity and, again, some might like having their cords be significantly lighter if they could.
    Last edited by MAC702; 12-11-2017, 06:40 PM.

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  • Almond farmer
    replied
    The machine was probably reengineered to reduce cost.
    Prefer the older design over the new XL design.

    Al was used for residential house wiring until some fires occured because of extra resistance from corroded aluminum oxide at connections.
    The national electrical code eliminated aluminum material house wiring.
    Difficult find or make an aluminum extension cord. Welding leads are all Cu.
    Found a commercial DC welder choke made from soft copper tubing on a straight ferrite round core.

    Leave a comment:


  • MAC702
    replied
    ... 50% is approximate...
    Okay, but 50% is an odd approximation of about 61%, especially when asking a technical question.

    Regardless, your question seems to imply the same amount (mass or cross-section) is used. But the machine is completely reengineered for the different material.

    Leave a comment:


  • Almond farmer
    replied
    Got the thermal conduction and electrical resistivity from "Matweb".... 50% is approximate.
    The physics of thermal conduction and resistivity are similar.

    The thunderbolt 225 draws 45.5 amps AC while the later model XL draws 47.5 amp AC according to the performance ratings in the Miller manuals.

    The LIncoln 225 AC 125 DC uses Cu in the primary and Al in the secondary, while the vintage 180 uses Cu in both and no cooling fan.
    Using the buzz box with no fan only reduces the duty cycle.

    Leave a comment:


  • MAC702
    replied
    ...Understand aluminum has 50% more resistance than copper, which means the transformer would generate more heat with AL with equal current on secondary for both AL & Cu.
    Where did you get that number?

    Obviously a machine with the different material would be engineered for the different material and not just had it substituted in. It would contain a greater volume of aluminum than a comparable copper machine.

    FWIW, aluminum has more resistance per volume but less resistance per mass.

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  • Almond farmer
    replied
    Reviewed all the Miller thunderbolt online operating manuals from 1982 to present, except the new inverter based 160 & 210 that have replaced the transformer based thunderbolt line and are no longer manufactured.
    1982 to 1998 , net weight for the 225 AC 150 DC is 114#.
    2000 to present weight is 104#, 10# weight reduction.

    Also 1982 to 1993 had an option for a power factor correction(PFC) capacitor = 4#, not a light weight.
    Capacitor is connected between the two input power leads and an extra transformer coil.
    PFC capacitor reduces input current by ~5 amp AC at 100% rated output current ,compared to the power source without PFC feature.

    The extra weight could be Cu transformer winding and rectified output choke winding.
    Last edited by Almond farmer; 12-09-2017, 07:04 AM. Reason: Changed from 5VAC to 5 amp AC

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