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  1. Thread: 230v VFD feed

    by JST
    Replies
    3
    Views
    200

    RPC voltage balance is generally "variable",...

    RPC voltage balance is generally "variable", since the voltage drop for a given current (impedance) of the generated leg is larger than for the "pass-through" legs.

    Result is that balance depends...
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    1,468

    It generally does that too, but it is intended to...

    It generally does that too, but it is intended to protect against overloads, as well as start and stop the motor.
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    1,468

    If you can get a 230V coil for that one, maybe. ...

    If you can get a 230V coil for that one, maybe. It does not appear that you will need to mess with a transformer, since the coil is full voltage.

    Re=wiring the motor to 230V, and changing the...
  4. Thread: VFD Cable

    by JST
    Replies
    21
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    1,568

    It;s not so much "grounding it at both ends"... ...

    It;s not so much "grounding it at both ends"...

    It's a "conductor" and you need to do what is best for the install and what is to be shielded. For a VFD you "connect" both ends, since it is a...
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    1,399

    Even then you may not get it to stay in when...

    Even then you may not get it to stay in when machined. Try to keep all the cutting having force "inwards" toward the holder.

    That means inserts or HSS that cut on the left side and not on an...
  6. Thread: VFD Cable

    by JST
    Replies
    21
    Views
    1,568

    Motor power has less to do with the problem than...

    Motor power has less to do with the problem than supply voltage and carrier frequency. A 480V motor has considerably more issue than a 230V motor.

    Some 230V seem not to have issues, some do. ...
  7. Replies
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    You said the most important thing about the...

    You said the most important thing about the company a while back, when you said everyone above the GM was "family", and he was married-in.

    You are not part of the place like they are.

    Those...
  8. Thread: VFD Cable

    by JST
    Replies
    21
    Views
    1,568

    Hmmmmmm. Well if the steering is bad, or the...

    Hmmmmmm.

    Well if the steering is bad, or the brakes don't work, I;d say the tires are not your issue.

    Yes, if not installed right, VFD cable is over-rated, and not a cure-all. And open wiring,...
  9. Replies
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    9,577

    Large thread here, and maybe I missed it. But...

    Large thread here, and maybe I missed it.

    But sometimes if the thread relief is not acceptable, on the thread, a recess in the head will work, if the threading tool will get in far enough to be...
  10. Replies
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    2,093

    As far as I know, only one pulley needs to be...

    As far as I know, only one pulley needs to be crowned. The belt will be stable then if the flat pulley is aligned right.

    So I am not "buying" the opposing force idea Doozer suggests, assuming I...
  11. Replies
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    1,468

    I feel VERY certain this refers to thinning the...

    I feel VERY certain this refers to thinning the end metal on the "rotor". That increases the resistance, and can decrease start current quite a bit.

    Unless more is done, it will generally not...
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    Sort-of. Many of the wires are connected...

    Sort-of. Many of the wires are connected together through the RPC's idler motor, so you would have to find the lowest resistance to identify the ends of one wire. That can be sufficiently...
  13. Thread: VFD Cable

    by JST
    Replies
    21
    Views
    1,568

    All of those are forms of "common mode" current....

    All of those are forms of "common mode" current. That typically IS the current that makes the most noise in an installation.

    That's the reason I suggested the ground wire. The "common mode"...
  14. Replies
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    1,468

    One of the wires from the (assumed to be) RPC at...

    One of the wires from the (assumed to be) RPC at the barn is the "manufactured" 3rd wire. That may drop in voltage when the motor is started, and might then have not enough voltage to close the...
  15. Thread: VFD Cable

    by JST
    Replies
    21
    Views
    1,568

    If you bundle the wires, or use multi-wire cable,...

    If you bundle the wires, or use multi-wire cable, and include a ground in the wire bundle that is connected from the VFD to the motor, you will have a lot less EMI emitted.

    Shielding is nice, but...
  16. Replies
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    5,800

    Scheeze...... After water has passed through a...

    Scheeze...... After water has passed through a few feet of normal clay-containing soil, it is pretty much drinkable straight. It only takes a couple feet of a sand filter to clean it to drinkable....
  17. Ford USED TO have pretty darn good QC...... ...

    Ford USED TO have pretty darn good QC...... I've seen the paint test, and other procedures that they USED TO USE. The QC course we had used the Ford QC manual as the text.

    It seems they are not...
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    3,677

    Couple of issues..... 1) If the manufacturer...

    Couple of issues.....

    1) If the manufacturer cannot get the parts, then you can't either. If the part is programmed, that's "proprietary IP", which literally cost them a million to develop,...
  19. Well, run it to something grounded. And to the...

    Well, run it to something grounded. And to the machine case.

    The case I would ground to the incoming ground. The X0 can be to that, also, and to the incoming ground if you like. That's...
  20. Replies
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    3,677

    They apparently used parts that are now obsolete....

    They apparently used parts that are now obsolete. THAT would require a new PWB, and testing, and fiull qualification, maybe UL submission..... all for a small amount of repair parts.

    So........ ...
  21. First, what's the transformer? 3p-3p delta-wye?...

    First, what's the transformer? 3p-3p delta-wye?

    As a rule, step-down are delta-wye, but there might be exceptions. As a separately derived system to run a branch circuit, X0 would be jumped to...
  22. Replies
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    3,677

    The problem with modern stuff is the...

    The problem with modern stuff is the specialization of parts. An IC to to "THAT" particular job. Cost less in high volume.

    Also becomes very expensive or true "unobtanium" when the large user...
  23. Well then, the amount of plating that the cheap...

    Well then, the amount of plating that the cheap plugs get has no chance of changing the dimensions enough. Same for the jacks. You are lucky that they got plated at all.

    The good plugs and jacks...
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    Do you have any link to pics of the innards? ...

    Do you have any link to pics of the innards? Inquiring minds want to pry........ IOW, I want to get a handle on what these gomers are actually making..... Been asked several times about them.
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    If properly spec'd, I'd expect those to be...

    If properly spec'd, I'd expect those to be in-place for life. The prior experience with capacitors does not suggest "properly spec'd" has always been the case, so we'll see.
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