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  1. Replies
    11$$
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    512

    140827-2220 EDT mbrooke: You are correct...

    140827-2220 EDT

    mbrooke:

    You are correct that at 60 Hz and the same excitation voltage as at 50 Hz that the core will be driven less into saturation. Will the slight reduction in excitation...
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    12$$
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    346

    140827-1100 EDT S_Dot: You list yourself as...

    140827-1100 EDT

    S_Dot:

    You list yourself as a power engineer. I would assume you could answer your own question, but I will try to clarify the question.

    Assumptions:

    The power company...
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    11$$
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    512

    140827-0905 EDT mbrooke: How do you squeeze...

    140827-0905 EDT

    mbrooke:

    How do you squeeze more kVA out of a transformer? Only if you were to raise the voltage.

    To a large extent a transformer rating is current limited by I^2*R losses....
  4. 140827-0814 EDT dmc1701a: Why ask us to...

    140827-0814 EDT

    dmc1701a:

    Why ask us to conjecture what is happening when you should use your voltmeter to investigate the circuit operation? You might answer your own question. I can not...
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    10$$
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    584

    140826-1632 EDT Some experiments on a Sq-D 500...

    140826-1632 EDT

    Some experiments on a Sq-D 500 SV1B transformer, about 20 years old.

    Measured unloaded power input and turns ratio. Applied 125.2 V to get 480 V on the primary. This is a ratio...
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    11$$
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    512

    140826-2235 EDT mbrooke: Assuming the...

    140826-2235 EDT

    mbrooke:

    Assuming the design critera was about the same for the 50 Hz transformer as would be used for the 60 Hz design, then when the 50 Hz unit is on 60 Hz the maximum flux...
  7. Replies
    11$$
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    512

    140825-2125 EDT No one should be propagating...

    140825-2125 EDT

    No one should be propagating such nonsense. Yes it is a myth.

    In a tightly coupled transformer, meaning a very high percentage of the primary magnetic flux couples to the...
  8. 140825-0917 EDT prs1jazz: What are your max...

    140825-0917 EDT

    prs1jazz:

    What are your max and min power values during the day shift when production is running? What is the typical kWHs per day?

    If the entire heating process from room...
  9. 140824-1950 EDT prs1jazz: I believe your...

    140824-1950 EDT

    prs1jazz:

    I believe your last post has now completely changed the question. Several aspects are not clear relative to the new question.

    You are a foundry. That may mean large...
  10. 140824-1556 EDT prs1jazz: Core loss is a...

    140824-1556 EDT

    prs1jazz:

    Core loss is a resistive load. Power factor correction has nothing to do with changing core loss (core loss is a resistive load, heat) except in very minor residual...
  11. 140824-0951 EDT mbrooke: You are still...

    140824-0951 EDT

    mbrooke:

    You are still confusing the mechanism by which electric current flows with a tool for analysis.

    When an electrical circuit is drawn on a piece of paper consisting of...
  12. 140823-2345 EDT mbrooke: By definition the...

    140823-2345 EDT

    mbrooke:

    By definition the direction of current flow in a "conventional current" analysis is that current flows from the most positive terminal of a load device to the more...
  13. 140823-1439 EDT mbrooke: As Besoeker said...

    140823-1439 EDT

    mbrooke:

    As Besoeker said it is by convention, meaning by definition.

    Direction of current flow was originally defined as from + to - in the external circuit before knowledge...
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    83$$
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    2,443

    140823-0030 EDT GITRDUN: There is something...

    140823-0030 EDT

    GITRDUN:

    There is something you are not tell us so far, and I do not believe you know what that something is.

    Some review:

    Many different CNC machines exhibt somewhat...
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    10$$
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    584

    140822-1316 EDT Power dissipation in a...

    140822-1316 EDT

    Power dissipation in a transformer will monotomically increase with load.

    We have a 2 kVA transformer on a chop saw to simply power a light and solenoid valves. Thus, it is...
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    10$$
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    584

    140822-1207 EDT You are taking the difference...

    140822-1207 EDT

    You are taking the difference between two large numbers and that can introduce large errors.

    I will make a guess that the power dissipation in the buck/boost at its full load is...
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    83$$
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    2,443

    140822-0926 EDT GITRDUN: Last night I...

    140822-0926 EDT

    GITRDUN:

    Last night I stopped by the shop and looked at our 3-96 VF-3. In the manual all the solenoid controlling items are drawn as a conventional electromagnetic relays. But...
  18. Thread: Blinking Lights

    by gar
    Replies
    101$$
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    4,445

    140821-2135 EDT The loop resistance for 80 ft...

    140821-2135 EDT

    The loop resistance for 80 ft of #4 aluminum is about 0.07 ohms. With a change of 100 A the voltage change is about 7 V. One half of this would be seen by a 120 V bulb. Or 3.5 V.
    ...
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    83$$
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    140820-1327 EDT GITRDUN: As an experiment I...

    140820-1327 EDT

    GITRDUN:

    As an experiment I would try a transient limiter on the secondary side of the main transformer on the output of what is labeled "Main Transformer" breaker..

    Nominal...
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    83$$
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    140820-1000 EDT GITRDUN: You did not...

    140820-1000 EDT

    GITRDUN:

    You did not indicate the year of the machine.

    Almost certainly these are pullup resistors. Because they are 10 K and in a multi-resistor package. I suspect it was...
  21. 140820-0957 EDT It is simple. Do the...

    140820-0957 EDT

    It is simple. Do the calculations and indicate your answers. There are three answers.

    .
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    83$$
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    2,443

    140819-0850 EDT GITRDUN: With reference to...

    140819-0850 EDT

    GITRDUN:

    With reference to your post #69.

    More information is needed.

    What specific breaker tripped? What resistor failed? What was the resistance, power rating, and type...
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    140817-2345 EDT Paul: Neither device is...

    140817-2345 EDT

    Paul:

    Neither device is being backfed by a parallel connection. Backfed in this case would require the output voltage to be higher than the input voltage.

    There may be some...
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    83$$
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    2,443

    140817-21027 EDT GITRDUN: With your above...

    140817-21027 EDT

    GITRDUN:

    With your above information I will look at the HAAS diagrams and see if there is any logical indication of what happens.

    Since only the "Main Transformer" breaker...
  25. Thread: Odd transformer

    by gar
    Replies
    7$$
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    433

    140817-0936 EDT Two Signal transformers...

    140817-0936 EDT

    Two Signal transformers ICT-H-A-20 connected to produce about 80 V from 480 can be used to generate a buck voltage for your desired about 400 V. If I interprete the information...
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