Three phase system

Discussion in 'Homework Help' started by feferry, Dec 8, 2005.

  1. feferry

    Thread Starter New Member

    Dec 8, 2005
    1
    0
    How would you determine proper phase sequence using an oscilloscope. Please detail connections and procedure.
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Hi,

    Pick a phase as a reference and display on ch 1. Pick another & see if it leads/lags the reference.

    Another quickie - if the motor runs the wrong way, just swap any two phases to correct.
     
  3. Sebi

    Well-Known Member

    Sep 24, 2005
    59
    0
    Or You can build a small flip-flop cct. for testing.
     
  4. dougp01

    Member

    Dec 6, 2005
    27
    1
    Three phase systems operate on 120 degree angles. If you reference phase A with one o'scope probe, a second scope probe will show phase B lagging A by 120 degrees, and phase C should lag A by 240 degrees.
     
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