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  1. Replies
    12$$
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    113

    150803-0723 EDT fifty60: Why would you put...

    150803-0723 EDT

    fifty60:

    Why would you put an un-necessary load on the transformer, and why would you leave an unloaded transformer powered when there is no-load for a long time? You question...
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    17$$
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    573

    150725-0856 EDT Note: the three second cycle...

    150725-0856 EDT

    Note: the three second cycle time. At 8766 hours per year this is 8766*60*60/3 = 10,519,200 cycles per year. The relays in the proposed power supply are very unlikely to last...
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    16$$
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    450

    150722-2112 EDT EdCampbell: See...

    150722-2112 EDT

    EdCampbell:

    See https://reinventingscience.wordpress.com/tag/selenium-rectifier/ . Current rating about 50 mA/sq-cm, or 50 * (1.5 * 2.54) * (1.5 * 2.54) = 50 * 14.5 = 725 mA for...
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    16$$
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    450

    150721-2211 EDT EdCampbell: Looks like a...

    150721-2211 EDT

    EdCampbell:

    Looks like a bridge rectifier.

    I believe terminals 3 and 5 are the DC output. These go to "output to solenoid valve", and "common for solenoid value". My guess is...
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    4$$
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    274

    150715-0959 EDT crazybott19: I quickly...

    150715-0959 EDT

    crazybott19:

    I quickly looked at the data on the WSD PDT 2P at http://www.sensorswitch.com/OnlineCatalog.aspx?sn=WSD%20PDT%202P
    and it looks interesting.

    You need to do some...
  6. Replies
    73$$
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    3,239

    150705-2332 EDT kwired: Your comments are...

    150705-2332 EDT

    kwired:

    Your comments are basically correct.

    The people in government are writing the laws and regulations, and the car and truck companies have to follow these...
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    73$$
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    3,239

    150705-1309 EDT kwired, and others: The...

    150705-1309 EDT

    kwired, and others:

    The government is driving design. To meet fuel economy requirements the vehicles must become lighter. This means using more expensive higher strength...
  8. Replies
    73$$
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    3,239

    150705-0930 EDT Fuel economy regulations are...

    150705-0930 EDT

    Fuel economy regulations are the driving force behind smaller engines and many gear ratios in multispeed transmissions. A neighbor that works for GM is working on something like a...
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    5$$
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    542

    150705-0858 EDT EE_FSU: I found your...

    150705-0858 EDT

    EE_FSU:

    I found your question quite confusing.

    There are various ways of using a single transformer (a true 3 phase transformer), or multiple transformers ( 2, 3 or more...
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    35$$
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    1,640

    150630-1007 EDT Roger: Sorry, I did not...

    150630-1007 EDT

    Roger:

    Sorry, I did not realize the original material was his.

    .
  11. Replies
    35$$
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    1,640

    150620-0913 EDT flinnagin72: To make a...

    150620-0913 EDT

    flinnagin72:

    To make a direct precise copy of a picture or written material without permision is a violation of copyright law.

    If you take a photo of anything then that is...
  12. Replies
    6$$
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    474

    150629-1045 EDR Aluminum oxidizes very quickly...

    150629-1045 EDR

    Aluminum oxidizes very quickly in air. Chemistry class. Aliminum oxide is a good insulator. Anodized aluminum has a thicker oxide layer than just the normal oxide layer of aluminum...
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    28$$
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    1,244

    150627-1451 EDT Some experiments. Use a...

    150627-1451 EDT

    Some experiments.

    Use a high impedance meter.

    1. Have someone drive car into position. Another person measures the instantaneous voltage from car body (a conductive location)...
  14. 150627-1022 EDT petersonra: You have a good...

    150627-1022 EDT

    petersonra:

    You have a good suggestion.

    One link to Sola is:
    http://www.solahevidutysales.com/pdf/ups/SDU-DC-DIN-Rail-UPS.pdf

    .
  15. 160627-0906 EDT Tony S: Why did I suggest a...

    160627-0906 EDT

    Tony S:

    Why did I suggest a car battery?

    The original post indicated a UPS. Instead of using a UPS I was suggesting a battery at the input of the PLC and using a regulated...
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    2$$
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    378

    150626-0920 EDT The plot I originally included...

    150626-0920 EDT

    The plot I originally included was a fairly high resolution .PNG file that imported with greatly reduced line quality. Thus, not very readable. Here I am trying again. This time...
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    2$$
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    378

    Power plot of a CNC machine cycle.

    150625-1923 EDT

    Attached is a power plot of one cycle of a HAAS VF3 CNC machine drilling and tapping a 1/4-20 hole.

    The measurement was made with a TED 1000 System. The primary supply is an...
  18. 150625-0855 EDT I would be inclined to...

    150625-0855 EDT

    I would be inclined to directly connect a 12 V car battery to the PLC power input, and charge the battery and power the PLC with a voltage regulated power supply with vertical...
  19. Thread: Batteries

    by gar
    Replies
    6$$
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    605

    150624-2343 EDT preenee1: Exactly what...

    150624-2343 EDT

    preenee1:

    Exactly what winnie said.

    If you do not have knowledge of calculus, then a way to see how power in the load varies as load resistance varies with constant source...
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    7$$
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    271

    150623-1128 EDT My Fluke and Beckman DVM (RMS...

    150623-1128 EDT

    My Fluke and Beckman DVM (RMS reading) are good to about 25 to 50 kHz on the high end. The Fluke 27 (average reading) has a somewhat higher upper frequency, and Simpson 270 (higher...
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    15$$
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    653

    150622-1958 EDT Some Internet reports indicate...

    150622-1958 EDT

    Some Internet reports indicate that the short circuit current of a 9 V battery may be in the range of 5 A for several seconds. Not a safe choice for a classroom setup.

    Consider...
  22. Thread: motor ?

    by gar
    Replies
    5$$
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    376

    150620-0846 EDT I tried Google Books to see if...

    150620-0846 EDT

    I tried Google Books to see if I could bring up the graph, but only a top portion of the graph showed. Now it appears that Google is providing only very small snippets of...
  23. Thread: motor ?

    by gar
    Replies
    5$$
    Views
    376

    150619-1956 EDT A sample set of calculated...

    150619-1956 EDT

    A sample set of calculated curves for an induction motor are shown on p 213 in Fig. 13-12 of "Alternating-Current Machinery", by Bailey and Gault, 1951, McGraw-Hill.

    Above 50%...
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    33$$
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    1,827

    1912 Switchboard

    150619-1013 EDT

    The following photos are not very good resulting from the plexiglas enclosure and the reflection of the close by brick wall. This was 250 V DC with 20,000 A meter, rated 4000 kW.
    ...
  25. Replies
    33$$
    Views
    1,827

    1912 Switchboard

    150619-1013 EDT

    The following photos are not very good resulting from the plexiglas enclosure and the reflection of the close by brick wall. This was 250 V DC at 20,000 A.


    12787

    12788
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