Synchro Stator Voltage Spreadsheet

Discussion in 'Electronics Resources' started by john-campbell, Feb 11, 2009.

  1. john-campbell

    Thread Starter Member

    Feb 10, 2009
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    For the uninitiated, synchros are devices that transmit angular information from one place to another. Superficially they look like little motors. When the synchro transmitter rotates through a given angle the synchro receiver will rotate thru the same angle. There are many variations of these devices, as well as synchro-to-digital (S/D) and digital-to-synchro (D/s) converters. I have attached a spreadsheet which calculates the stator voltages for angles between zero and 359. Ultimately, I would like to develop the spreadsheet to show the calculated values when there are faults present; such as, reversed, open or shorted connections. Does anyone else have anything along these lines?
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
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    Not to be too flippant, but that might not be totally valuable, at least for 3 phase synchros. When the connections are reversed, the receiver is 180 deg out. If open, the receiver just sits there. And a short either pops a fuse or causes smoke to appear.

    If you're worried about the accuracy of the S -> D or D -> S converter, the table you have should be adequate.
     
  3. KL7AJ

    AAC Fanatic!

    Nov 4, 2008
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    I had a pair of synchros when I was a kid. I thought they were the coolest thing on the planet! My brother and I set up a "telegraph" between our bedrooms using synchros and a dial with the letters of the alphabet and a pointer. When you pointed one to an A, the other one tracked.

    We were easily entertained, I guess. :)

    Eric
     
  4. john-campbell

    Thread Starter Member

    Feb 10, 2009
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    Thanks for the replies. Some of the impetus behind the spreadsheet was simply a thought experiment to calculate the stator voltages when various troubles were present. I'm not sure where this might lead. Maybe nowhere.
    See attached excerpts from MIL-HDBK-225 which describes numerous possible faults.
     
  5. john-campbell

    Thread Starter Member

    Feb 10, 2009
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    I'm guessing you're still easily entertained. With me it was a telegraph made out of a couple of cigar boxes.
     
  6. Philbilly

    New Member

    Aug 18, 2009
    7
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    I understand your thought experiment and have some of the same basic questions. My problem is the math equation for determining the angle of rotation when the Z leg is intentionally grounded (Going back twenty-five years, I believe this make the synchro a resolver).
    All of my plots in Excel produce 180 degrees of resolution, meaning the addition of the X and Y leg produce a sine wave which have two points at zero volts. Thus the encoder cannot distinguish between the 0 degree and 180 degrees.

    Suggestions are welcomed.
     
  7. Paul Snyderwine

    New Member

    Apr 12, 2011
    1
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    Thanks, john-campbell. This will be useful in explaining synchros to co-workers.

    I am interested in calculating the "line to neutral" components, so that I could set up four synchronized sources R2-R1, S1-N, S2-N, S3-N so that I can test a synchro receiver without using a TR or simulator.

    Can you point me to the required math? I do understand that all voltages are either in phase or "180-out", and that the math may be surprisingly simple.

    Again, thanks!
     
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