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  1. Replies
    8$$
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    150417-1001 EDT rhenders: You should have...

    150417-1001 EDT

    rhenders:

    You should have been able to answer that question yourself, but is there more to the real question.

    Depending upon on the motor characteristics you might be able to...
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    12$$
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    150417-0843 EDT Buck Parrish: Why does your...

    150417-0843 EDT

    Buck Parrish:

    Why does your customer want to switch off this entire subpanel? What are the actual loads? How many circuits?

    Rather than a single contactor you could consider...
  3. 150416-2555 EDT A basic equation to this...

    150416-2555 EDT

    A basic equation to this problem is the differential equation:

    vsource = i*R + K*N*dPhi/dt

    v is the driving source voltage
    i is the magnetizing current
    R is the series loop...
  4. 150416-2352 EDT I do not understand your...

    150416-2352 EDT

    I do not understand your description. You need to draw a diagram of the circuitry on the 24 V side of the transformer. The transformer is of no importance to your problem. It is...
  5. 150415-1933 EDT Bugman1400: I provided a...

    150415-1933 EDT

    Bugman1400:

    I provided a portion of one B-H curve in post 6. This was a hysteresis curve. Basically there are two types of B-H curves generally presented. These are...
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    8$$
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    150415-1702 EDT jason619: Go to the...

    150415-1702 EDT

    jason619:

    Go to the following location and download the datasheet. This is for the P&B KUP relay family.
    ...
  7. 150413-1514 EDT Phil: Please describe your...

    150413-1514 EDT

    Phil:

    Please describe your statement What were the initial conditions for the "case above". From this very loose statement how do you conclude "twice"?

    What is the meaning of...
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    8$$
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    150412-2360 EDT Upnorth: In general you can...

    150412-2360 EDT

    Upnorth:

    In general you can not just use a relay with a higher resistance coil to reduce power dissipation and do the same mechanical job (work).

    Within some limited range...
  9. 140411-1706 EDT Phil: At 60 Hz eddy current...

    140411-1706 EDT

    Phil:

    At 60 Hz eddy current (also called Foucault current) and hystersis losses are about equal. This is achieved by the selection the core material and the lamination...
  10. 150411-0844 EDT Phil: This is not obvious...

    150411-0844 EDT

    Phil:

    This is not obvious and not correct, if I understand what you said. Refer to Attwood's hysteresis graph that I presented in post #6.

    Under steady-state AC excitation...
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    150410-0929 EDT Study the Insteon website. ...

    150410-0929 EDT

    Study the Insteon website.

    A wall switch, and I believe there are several types (relay, solid-state, dimmable), are locally switchable at the switch location, and are remotely...
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    7$$
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    150409-0855 EDT You have two choices for...

    150409-0855 EDT

    You have two choices for switch replacements that don't require any new wiring. X10 type switches that use PLC (power line communication), or RF communication. Insteon is a PLC...
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    7$$
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    150408-2350 EDT I don't understand the...

    150408-2350 EDT

    I don't understand the requirements.

    There are 10 outside lights to be controlled from many locations. These are not all fed from the same circuit source.

    What is not clear...
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    150408-1629 EDT Define a control cable? I...

    150408-1629 EDT

    Define a control cable?

    I can send 115.2 kbaud data over 4000 ft. I can send simple DC signals over thousands of feet. Note 5280 feet is 1 mile. I can send data over long...
  15. Thread: Energy cost

    by gar
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    2$$
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    187

    Energy cost

    150408-1139 EDT

    My energy cost for last year was:

    $ 0.162 / kWh for electricity.
    $ 0.847 / CCF for natural gas.

    There are 29.31 kWh per 1 CCF.

    Cost of natural gas in kWh is:
  16. Replies
    7$$
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    150407-2205 EDT chris kennedy: You can not...

    150407-2205 EDT

    chris kennedy:

    You can not do it from two analog pots unless the highest or alternatively the lowest was to dominate. Thus, there has to be a stepping type control, or another...
  17. 140407-1550 EDT Following is a part of what I...

    140407-1550 EDT

    Following is a part of what I had started as a reply to the other thread.

    150405-1412 EDT

    GoldDigger:

    On reflection I want to try to clarify flux or flux density in a...
  18. 150407-0830 EDT Electric motors, generators,...

    150407-0830 EDT

    Electric motors, generators, transformers, and resistance heating elements can tolerate rather large short time overloads. DC motors and generators 10 times or more, except some...
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    37$$
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    150406-1903 EDT Strathead: Power is not...

    150406-1903 EDT

    Strathead:

    Power is not work. Power is the rate of doing work. The integral of power over time is work. Mathematical integration is the summation of small increments over some...
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    37$$
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    1,256

    150405-2424 EDT Time out limits are a major...

    150405-2424 EDT

    Time out limits are a major problem on this form. Thus, I won't recompose what I had tried to add.

    Go to my wesite http://beta-a2.com/energy.html and view graphs 9.8.2.2 and...
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    150405-2344 EDT zcanyonboltz: I have not...

    150405-2344 EDT

    zcanyonboltz:

    I have not read all the posts so I may be repeating what has been said.

    Watts (power) is a measure of the rate of doing work. This is like the speed of a car....
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    31$$
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    140405-2153 EDT chris: An unloaded...

    140405-2153 EDT

    chris:



    An unloaded transformer has an inrush current that is not the same every time power is applied to the transformer. The inrush can be all over a large range. The value...
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    31$$
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    150405-2121 EDT GoldDigger: I should have...

    150405-2121 EDT

    GoldDigger:

    I should have been more clear. Hysteresis can not be ignored. The magnetizing current drives the ferromagnetic material to some flux level. When the magnetizing...
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    31$$
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    761

    150405-1929 EDT chris kennedy: My...

    150405-1929 EDT

    chris kennedy:

    My suggestion is that you contact the transformer manufacturer and ask for a recommended breaker.

    On your theory question:

    As an approximation a switch,...
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    31$$
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    761

    150403-9840 EST Not really. However, there may...

    150403-9840 EST

    Not really. However, there may be some emperical ratios that are used relative to transformer kVA, and the type of transformer.

    In a sense the real question is what is the...
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