Why do they use phase dots throughout this schematic?

Discussion in 'Technical Repair' started by donovan_digital, Aug 3, 2016.

  1. donovan_digital

    Thread Starter New Member

    Feb 2, 2013
    9
    0
    Surely they do not mean to suggest that _any_ of these inductors form a transformer, intentionally or otherwise?

    [​IMG]
     
  2. #12

    Expert

    Nov 30, 2010
    16,316
    6,818
    The polarity dot indicates which way the winding is wound. No, it doesn't mean these are transformers. Transformers have at least two windings on a core. Some of these symbols are just habits or idiosyncratic behaviors a draftsman might have. My sister made some truly unreadable schematics because she was a drafts person, not an engineer. I probably do some stuff you would call weird, just because I started in the 1960's. Schematics are made in many different countries and use many different, "standards". You're going to meet a lot more strange symbols in the next few years.
     
  3. OBW0549

    Well-Known Member

    Mar 2, 2015
    1,320
    889
    I suspect not; more likely, just a careless choice of inductor symbol when drawing the schematic. Oddly, one of the inductors, the 1.95 mH inductor second from the left in the group of four in the upper right hand corner of the schematic, does NOT have a polarity dot.
     
  4. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
    5,699
    905
    As others have said, the inductors are probably not coupled. However, the dashed box around each set may imply otherwise.

    Can you provide a link to the original?

    John
     
  5. donovan_digital

    Thread Starter New Member

    Feb 2, 2013
    9
    0
  6. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,553
    2,375
    That is normal marking for dual/triple reactor chokes, triple as used in VFD both supply and motor line.
    [​IMG]
    Max.
     
  7. JoeJester

    AAC Fanatic!

    Apr 26, 2005
    3,373
    1,159
    There can be mutual inductance and the dots indicate phasing. In the upper right, the opposite phasing of the one transformer can affect the other three.

    I would not discount that to poor draftsmen, as those are typically reviewed and approved by an engineer, somewhere in the scheme of things.
     
Loading...