The formal designation and full title for this standard that was published in April 2020 is, “CSA C392:20 Testing of Three-Phase Squirrel Cage Motors During Refurbishment.” This is the second edition of the standard and supersedes the previous edition published in 2011. The standard focuses on the identification of those tests that help to determine whether the efficiency of a motor is maintained after it is “refurbished,” without requiring a motor efficiency test.
Changes have been made throughout the standard. Test procedures have been reorganized for clarity. Requirements have been updated to reflect current capability of test equipment. Of particular interest to service centers is a new Annex that describes a method using algorithms to estimate partial and full-load efficiency based on no-load tests.
The detailed descriptions of the tests to be performed make this standard very useful as a reference and a how-to document for any service center, not just those in Canada. These are the key tests that should be performed to help verify that efficiency has been maintained during the rewind and repair processes. These key tests are stator winding resistance, stator core magnetic circuit (laminations) test, rotor test and no-load and inspection test. The individual clauses for each of these tests provide the purpose of the test, a flowchart of the steps in the test, test description and procedure, calculations and analysis of the results.
EASA Senior Technical Support Specialist Tom Bishop, P.E., and Frank Conci of EASA member firm AC Motor Electric Ltd. in British Columbia were members of the CSA subcommittee that oversaw revision of the standard. The 75-page standard document can be purchased from CSA at go.easa.com/csa.
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