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Type: Posts; User: JST

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  1. Replies
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    KVA only has to be what is "added" by the...

    KVA only has to be what is "added" by the transformer. So the voltage and current in the boost transformer.... not the entire kVA number. If you add 10% voltage at the same current, all you need...
  2. Agree on that. The bigger the idler, the...

    Agree on that. The bigger the idler, the better that works.
  3. Replies
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    Heat the SMALL part (die) as much as you can...

    Heat the SMALL part (die) as much as you can quickly. Let it cool off and then try getting it out. With luck it will have crushed or loosened whatever is jamming it in there.
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    They also can draw a lot of current when...

    They also can draw a lot of current when perfectly fine, so high current draw may be totally normal under load.
  5. Or you can use a buck/boost transformer to do the...

    Or you can use a buck/boost transformer to do the balancing. That is far less load sensitive.

    The idler naturally produces a lower back EMF (on the generated leg) than the incoming voltage. ...
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    Those things are nice antiques. And, yes, they...

    Those things are nice antiques. And, yes, they store small.

    But, unlike the ratchets, they take much more room to use.

    Your use, your choice. I have a similar Niles set somewhere. I use...
  7. Thread: 230v VFD feed

    by JST
    Replies
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    681

    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...
  8. Replies
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    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.
  9. Replies
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    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...
  10. Thread: VFD Cable

    by JST
    Replies
    21
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    1,612

    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...
  11. Replies
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    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...
  12. Thread: VFD Cable

    by JST
    Replies
    21
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    1,612

    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. ...
  13. 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...
  14. Thread: VFD Cable

    by JST
    Replies
    21
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    1,612

    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,...
  15. Replies
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    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...
  16. Replies
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    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...
  17. Replies
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    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...
  19. Thread: VFD Cable

    by JST
    Replies
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    1,612

    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"...
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    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...
  21. Thread: VFD Cable

    by JST
    Replies
    21
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    1,612

    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...
  22. Replies
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    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....
  23. 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...
  24. Replies
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    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,...
  25. 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...
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