×
Follow Us
Page 2 of 2 FirstFirst 12
Results 11 to 13 of 13

Transformer Winding Resistance

 Jump to latest post
Page 2 of 2 FirstFirst 12
    #11
  1. SecondGen's Avatar
    SecondGen is offline
    I push buttons.
    NETA Level III Pro Subscriber
    Join Date
    Jan 2014
    Location
    United States
    Posts
    469
    Reputation
    Quote Originally Posted by changeabilities View Post
    Hi everyone, I hope you all doing okay. I wonder something and you are the best crew i can ask
    When we test winding resistance test for transformer we saw discrepancy in results when compare with the Factory Test results. Is there any way to calculate the result and see the true values? I research it but i couldnt find a good way.
    Thank already...
    As other have stated, I'd make sure you are using the exact same connections and test current as the factory test results. Also be mindful of additional bus you may be including, the readings you have wouldn't' raise alarm to me if I didn't see the factory results and my readings were within tolerance between each phase.

  2. #12
  3. Join Date
    Jun 2017
    Posts
    9
    Reputation
    Quote Originally Posted by changeabilities View Post
    Hi
    I want to try and calculate the values based off the voltage, current and power if its possible.
    So your winding resistance test set, what ever brand you use, should inject the winding(s) with a voltage and current. You usually can change the current you inject into the transformer. The results you got were the "true values" at the time. As windings heats up and if there are faults or contamination in the oil the resistance will go up; this is what changes your results from the factory. if you wanted to calculate the resistance you would just use ohms law. But that doesn't mean you will get a "true value" because no conductor is a perfect conductor and there is always capacitance and reactance.

    I hope that helps

  4. #13
  5. SecondGen's Avatar
    SecondGen is offline
    I push buttons.
    NETA Level III Pro Subscriber
    Join Date
    Jan 2014
    Location
    United States
    Posts
    469
    Reputation
    Quote Originally Posted by rmr660 View Post
    So your winding resistance test set, what ever brand you use, should inject the winding(s) with a voltage and current. You usually can change the current you inject into the transformer. The results you got were the "true values" at the time. As windings heats up and if there are faults or contamination in the oil the resistance will go up; this is what changes your results from the factory. if you wanted to calculate the resistance you would just use ohms law. But that doesn't mean you will get a "true value" because no conductor is a perfect conductor and there is always capacitance and reactance.

    I hope that helps
    Good point, I totally forgot to mention temperature is important as well. If you had just de-energized the transformer the winding temp will most likely be elevated and this should be corrected same as the factory results for true comparison.

Page 2 of 2 FirstFirst 12
Subscribe

Login or register to leave a reply!


Share this thread

Related Topics

  1. how to perform winding resistance test on transformer
    By mask12900 in forum Electrical Testing Talk
    Replies: 4
    Last Post: May 9, 2018, 08:21 PM
  2. Transformer winding resistance, balance ?
    By rgrabis in forum Electrical Testing Talk
    Replies: 3
    Last Post: January 19, 2018, 11:34 AM
  3. winding resistance tester and CPC 100
    By moon1958moon in forum Electrical Testing Talk
    Replies: 8
    Last Post: August 4, 2017, 12:09 PM
  4. winding resistance tolerance for a transformer test
    By Larry5441 in forum Electrical Testing Talk
    Replies: 6
    Last Post: June 29, 2015, 04:33 PM

Tags for this Thread



Related Content


Follow us


Explore TestGuy


NETA Certification Training


NICET Electrical Power Testing


Help and Support