Customer:

Wind Turbine Owner

Background: 

JJ Loughran was asked to overhaul a two speed 250KW/50KW Elin generator. The generator was originally 690VAC however this was incompatible with N.Ireland Grid requirements, our rewinding department changed the generator winding configuration to meet 400VAC grid requirements. We also carried out a full overhaul of the generator which included full bearing change, stove and varnishing of stator, balancing of rotor and a full respray of unit to original machine manufacturers specification.

The Solution: 

• JJ Loughran engineers carried out a full detailed mechanical and electrical inspection of the Elin generator in-house before it was disassembled, the generator winding integrity was also checked with our Baker tester.
• Engineering manager briefed the customers as to the extent of the works that needed to be carried out and their costs. This was discussed before any work commenced.
• We carried out a full disassembly and cleaning of all parts. A detailed inspection of Elin generators main components was also carried out.
• We measured all critical dimensions to ensure there was no mechanical wear on shaft, bearing housings or any other main mechanical components.
• JJ Loughran had to break into the copper core of the generator and change the winding configuration. We have extensive experience converting generators from 690 VAC Star to 400VAC Delta.
• Our engineers then had to Re-Terminate the winding connections using solder and heavy duty copper terminals. The  generator stator was then relacquered and stoved overnight.
• We then balanced the generator rotor on JJ loughran’s state of the art IRD soft balancing machine, which gives our customers the most accurate and comprehensive balancing reports.
• We Supplied and installed SKF Drive and Non- Drive end bearings as standard.
• We then tested the modified stator windings on our Baker tester to ensure the integrity of the repair. The following tests where preformed and result recorded.
  • Resistance
  • meg-Ohm
  • Surge
  • DC continuous ramped
  • step-voltage
  • polarization index (PI)
  • dielectric analysis (DA)
  • DC hipot ​
  • Once we confirmed that all the generators parameters where nominal, we then reassemble all parts and test run the turbine generator on our state of the art test bed. All results including rpm, vibration, torque, speed and amps are recorded.
  • A full re-spray of generator to original Elin specification was carried out
  • JJ Loughran delivered the reconditioned Elin turbine generator back to site in our new service vehicle.