Testing of three-phase squirrel cage induction motors during refurbishment
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This is the first edition of CSA C392.11, Testing of three-phase squirrel cage induction motors during refurbishment.
This Standard provides guidance to electric motor service centres in verifying that the refurbishing process has maintained or enhanced the electric motor (hereafter motor) efficiency. It is also intended to provide a reliable evaluation of any changes in the condition of the motor, with respect to its efficiency, that might have resulted from its failure.
The intent of this Standard is not to prescribe which tests should be performed on any given motor requiring repairs; rather, it is to establish a consistent methodology for conducting the tests described herein. The applicability of these tests depends on the type of failure encountered, the repair work to be performed, and the need to confirm that no change in efficiency has occurred as a result of damage to the motor and its repair. The motor end user and the service centre should mutually determine which tests are applicable or useful in a given situation to establish the scope of testing during the repair process.
Motor efficiency can be depreciated by the damage caused during motor operation or failure mode. In cases where the test results do not comply with the pass/fail criteria, it is not the intent of this Standard to require that the motor be removed from service. However, the test results might assist in future repair/replace decisions and future energy conservation planning.
The tests and pass/fail criteria are standard in the motor service centre industry in North America.
There are many additional tests and inspection procedures employed when refurbishing AC motors that are not part of this Standard because they are not directly related to motor efficiency. Many of these additional tests are available in the publications referenced in Clause 2 and Annex C. Not all of these tests can or should be administered on every motor that is to be refurbished. It is the responsibility of the motor service centre in consultation with the end user to determine which tests are applicable.
The tables and calculation procedures, provided in this Standard to estimate the impact on motor nominal efficiency, contain typical data and should be used with the understanding that these procedures are estimates based on the information available and that actual results can vary.
This Standard covers integral horsepower, three-phase, alternating current, squirrel cage induction motors rated 200 to 13 200V at 60 Hz. This Standard also covers motors operating on variable frequency drives.
Note: This Standard might be useful and may be applied with discretion to products outside the scope of this Standard.