Strand test for new winding
Strand test for new winding
(OP)
Can anyone please explain what's a strand test for a new winding of an electric generator? Thank you.
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Strand test for new winding
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RE: Strand test for new winding
I did a search on google and came up with the following:
http://www.irscoil.com/qualitycontrol.shtml
It looks like strand to strand test is an optional quality test for new coils. I'm not sure exactly how they do it (there is a photo). Perhaps they check insulation resistance between strands (before making the end connections which would short the stands together). I don't know what test voltage would be appropriate (250vdc?) or what acceptance criteria is applied.
Interested to hear more comments from others.
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RE: Strand test for new winding
RE: Strand test for new winding
electricpete has a very good research about the topic..it is all about quality control on new winding.
STRAND TEST is intend to test insulation resistance failure between wire conductors especially on pre-formed coils (high voltage coils) where it revails or detects the inter-turn shorts on single coil. This test is also verified with almost the same result using SURGE COMPARISON TEST where we used to test the coil prior on putting it on in the slots.
RE: Strand test for new winding
RE: Strand test for new winding
Strand test (entirely different from surge test) is applicable only to single turn, multi conductor roebel bars. At sites, where the winding is already completed, this test cannot be done.
RE: Strand test for new winding
RE: Strand test for new winding
I have seen this done after coils have been stored for a long period of time. At least I thought I had. What was it that I was watching when the test tech hooked up and tested each strand against the other strands. Maybe I have the name of the test wrong. The coil supplier (a large one that I'm sure you all know) told me that it was a strand insulation test.
RE: Strand test for new winding
What you describe is indeed a strand test. But normally, it is a factory test, where you reject the bars that fail the test. At sites, it may be done on spare coils (that are to be used for a partial rewind) to ensure no strand shorts. However, it is moot, whether bars which passed factory strand test will develop shorts in storage at site.
RE: Strand test for new winding
I was just witnessing the suppliers crew conducting the list of tests that came in the procedure. I would agree it doesn't seem very logical.