Follow Us
Page 2 of 2 FirstFirst 12
Results 11 to 11 of 11

XFMR test question - wye-delta TTR

Go to latest post
Page 2 of 2 FirstFirst 12
  1. Join Date
    Jun 2015
    Quote Originally Posted by Kalbi_Rob View Post
    WI | DE

    So, easy way to remember how to perform turns ratio is to start with the acronym WIDE where WI stands for Wye where current is equal between phase and line, and DE stands for Delta where E (electromotive force which also defines voltage) or voltage is equal between phase and line.
    So, on the Wye side of the transformer you need to take the voltage (assume to be phase voltage if not otherwise noted) and divide by square root of 3 (or ~1.73). So the equation is
    (7200V/(sqrt(3))/480V = 4156.9V/480V = 8.66 so the TTR = 8.66:1

    Turns ratio is only taken on single phases of a transformer, so all values need to be reduced to individual line values to represent each single phase. This is also why you see a 12kV/480 delta/wye transformer with voltage values of 12kV - 480Y/277V.
    If for whatever reason you needed to convert current values from phase to line on a Delta Xfmr, then you take phase current and divide by sqrt(3).
    thank you. this is very helpful.

Page 2 of 2 FirstFirst 12

Login or register to leave a reply!

Related Topics

  1. Insulation resistance test set question
    By mkennedyShermco in forum NETA Level 4 Exam
    Replies: 2
    Last Post: June 10, 2018, 12:52 PM
  2. Replies: 3
    Last Post: January 7, 2018, 01:23 AM
  3. Test Question--High Current Injection
    By alexlounsbury in forum NETA Level 3 Exam
    Replies: 5
    Last Post: July 10, 2017, 11:38 AM
  4. Replies: 2
    Last Post: February 2, 2016, 01:35 PM
  5. Replies: 4
    Last Post: January 24, 2015, 01:34 PM

Related Content

Tags for this Thread

Follow us

Explore TestGuy

NETA Certification Training

NICET Electrical Power Testing

Help and Support