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  1. Replies
    18$$
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    218

    141122-1823 EST The approximate currents are...

    141122-1823 EST

    The approximate currents are 10.1, 5.77, and 7.22 for your sketch 2. Your other currents are OK.

    The calculations are:

    3 kW 3000/600 = 5 A
    4 kW 4000/600 = 6.6667 A
    1 kW...
  2. Replies
    18$$
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    218

    141122-1554 EST You misunderstood my comment...

    141122-1554 EST

    You misunderstood my comment on average measurement of an AC sinewave vs an RMS measurement of that same curve.

    An average measurement of a half rectified full cycle sine wave...
  3. Replies
    18$$
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    218

    141122-1358 EST What does pulse width...

    141122-1358 EST

    What does pulse width modulation mean? Is this phase control of SCRs, or is it "bang-bang" control of the contactor?

    If you are dealing with sine wave current, then vector math...
  4. Replies
    18$$
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    218

    141122-1307 EST Is the resistive load wired as...

    141122-1307 EST

    Is the resistive load wired as a delta or wye?

    32 resistors are not evenly divisible by 3. Thus, inherently unbalanced.

    Is there any phase shift or on-off cycling of the...
  5. Replies
    9$$
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    193

    141122-0840 EST What is an Ultra? The C-H...

    141122-0840 EST

    What is an Ultra? The C-H website seems to use the name across several models.

    The statement that fire comes out of whatever outlet the customer is near implies that fire would...
  6. Thread: Cogeneration

    by gar
    Replies
    2$$
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    135

    141121-2113 EST Pedro jr: See...

    141121-2113 EST

    Pedro jr:

    See http://en.wikipedia.org/wiki/Cogeneration .

    ,
  7. Replies
    9$$
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    199

    141121-1241 EST If you have a composite video...

    141121-1241 EST

    If you have a composite video base band signal with a coaxial cable communication path, the source will probably be 50 ohms and the far end of the cable should be terminated with...
  8. Replies
    9$$
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    193

    141121-1153 EST At our shop we had a problem...

    141121-1153 EST

    At our shop we had a problem one time. This is a three phase open delta system with a center tapped single phase transformer. Center tap is grounded. The single phase transformer...
  9. Replies
    7$$
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    147

    141120-2057 EST Fundamentally you need about a...

    141120-2057 EST

    Fundamentally you need about a 1500 VA transformer so go with 2.5 or 5 kVA to get a lower impedance. Primary 112 V with a 10 V secondary as a boost source.

    .
  10. Replies
    5$$
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    165

    141120-2033 EST sdickson: I do not know how...

    141120-2033 EST

    sdickson:

    I do not know how your circuit works.

    I assume the current transformer at the top of the last photo is the one under test.

    The transformer on the right has...
  11. Replies
    5$$
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    165

    141120-1627 EST Your drawings are too small to...

    141120-1627 EST

    Your drawings are too small to read easily, and I don't want to wade thru all the detail either.

    So to the basics.

    You need a transformer with a rating of possibly 50 A on...
  12. 141120-1211 EST well grounded: If you have...

    141120-1211 EST

    well grounded:

    If you have a positive transient spike of 61 V peak centered at a voltage positive zero crossing, then will this trigger a transient event? The peak of this...
  13. 141120-0911 EST well grounded: A list of...

    141120-0911 EST

    well grounded:

    A list of times with no amplitude and duration information is of little value other than to indicate something occurred.

    What does 50% RMS 120 V mean? For...
  14. Thread: 90 amp altenator

    by gar
    Replies
    16$$
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    402

    141119-0646 EST donmic: My ITT Reference...

    141119-0646 EST

    donmic:

    My ITT Reference Book provides the following information for copper:

    .... # 14 ......... # 12 ......... # 10

    2.525 ........... 1.588 ........ 0.9989...
  15. Replies
    21$$
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    705

    141118-2354 EST codetalker: I would...

    141118-2354 EST

    codetalker:

    I would describe your approach as a kluge.

    I believe you now may be required to run a neutral to each switch box. Also your approach does not eliminate the...
  16. Replies
    23$$
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    515

    141118-1309 EST What is the total cost of two...

    141118-1309 EST

    What is the total cost of two 25 kVA single phase vs one 75 kVA three phase transformer?

    What is the core loss comparison of the above two possibilities?

    .
  17. 141117-1421 EST well grounded: I don't see...

    141117-1421 EST

    well grounded:

    I don't see any transients in your latest waveforms. All I see is the small square ripple on the sine wave which appears to be your instruments sampling rate. If...
  18. 141117-1415 EST Eh40: The TED 1000 had a 1...

    141117-1415 EST

    Eh40:

    The TED 1000 had a 1 second integration time, the TEDs since then are 2 seconds or worse even though TED states 1 second.

    From the manual the Amprobe that 5 S electric...
  19. 141117-0814 EST The first scope trace appears...

    141117-0814 EST

    The first scope trace appears to show a single full cycle moderately high frequency, relative to the power line frequency, oscillation that is triggered somewhere near the line...
  20. 141115-1045 EST 5 S electric: You have...

    141115-1045 EST

    5 S electric:

    You have spent a lot of money and time trying to solve your problem. Had you used the correct instrumentation and correctly I believe the problem area could have...
  21. 141114-1725 EST 5 S electric: I have never...

    141114-1725 EST

    5 S electric:

    I have never worked with your Amprobe instrument, but looking at the manual you need to have it setup for Voltage Anomalies. I don't believe you have done that. I...
  22. Replies
    21$$
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    705

    141114-1035 EST masterinbama: Of the RR...

    141114-1035 EST

    masterinbama:

    Of the RR failures you encountered what was the cause of failure?

    I have had no coil burnouts because of my system design, but I have had several that lost...
  23. Replies
    21$$
    Views
    705

    141114-1018 EST codetalker: Can you clarify...

    141114-1018 EST

    codetalker:

    Can you clarify your last post.

    What is it that you actually want to learn?

    You list yourself as an EE. What were your schools, degrees, and areas of...
  24. Replies
    21$$
    Views
    705

    141113-2117 EST codetalker: The GE RR relay...

    141113-2117 EST

    codetalker:

    The GE RR relay has no UL or NEC problems.

    For a fairly complete description see:
    https://www.vikingelectric.com/Images/img/043180/GE%20RS2-37.pdf

    .
  25. Replies
    21$$
    Views
    705

    1411130-1611 EST codetalker: The GE RR...

    1411130-1611 EST

    codetalker:

    The GE RR relay is a mechanically bistable relay with silver contacts, and a set and reset coil set.

    Thus, a wired logical "or" set of momentary switches in...
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