Our expert staff and specialized facilities offer the know-how and in-depth experience to deliver reliable engineering services and testing capabilities that can help prevent equipment failures, reduce maintenance and improve day-to-day operations for utilities.


Digital EL CID Tests


Interlaminar integrity of the stator core is a key issue in unit operation and maintenance.  Breakdown of interlaminar insulation resistance and shorting between core laminations can lead to abnormal currents, which may reach high levels if the breakdown is over many laminations and the fault resistance is low.  If localized heating is severe, the fault zone may enlarge, possibly jeopardizing adjacent coil or through bolt insulation.  Undetected, progressive deterioration could require repair, ranging from partial to total stator rewind, with replacement of substantial portions of the core.

Electromagnetic Core Imperfection Detection (EL CID) is used to check the integrity of interlaminar insulation for stator cores of generators and motors. A fault current occurring within the laminated stator core results in a hot spot and can cause a catastrophic failure of a generator and motor in service. An EL CID test can

  • detect faults and defects in the stator core;
  • check effectiveness of core repairs;
  • test the stator core before and after a stator rewind to check any damages caused by rewind;
  • check the quality of a new stator core; 
  • trend the stator core condition.

In comparison with a traditional loop (ring flux) test, an EL CID test offers the following benefits:

  • Uses a portable excitation transformer instead of a large excitation transformer in a loop test to considerably reduce test cost;
  • Saves 30% of test time and labor cost of a loop test.
  • Conducts low power testing (EL CID uses only 4% of the rated magnetic flux) to avoid further damage to fault areas;
  • Does not have safety concerns to test personnel;
  • Records test data by a computer for trending of test results.
  • Provides an easy and in-expensive test method to check the quality of a core repair or a re-wedging operation.

EL CID testing requires good knowledge of the EL CID instrument and stator cores to give a reliable test result. PT. Mesindo Tekninesia has been fully supported by Powertech. Lab. Inc of Canada is a certified of EL CID testing provider.

Site works

To eliminate the  time consumption,  Our specialist  team engineer can asses machine condition, repair  and outage at site, the following site activities was conducted outage and upgrading of  wedge stator 250 MVA / 15 KV / 3000 RPM Toshiba generator from conventional method has been upgraded by radial spring.