Luse Coils Generator & Turbine Repair Serices


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Luse Coils Generator & Turbine Repair Serices

  1. 1. SERVING Industry SINCE 1923 And Our Partnership Team providing Inspection ,Testing , & Repair of Generators, Turbines, & Stators
  2. 2. Generator Testing & Inspection
  3. 3. Generator Services• Field Services• Stator Services• Testing & Inspections• Hydraulic Integrity Test (HIT)• Liquid-Cooled Clip Repairs• High Voltage Bushings• Reverse Engineering
  4. 4. Generator Field Services Turnkey Rewinds Technical Direction Retaining Ring Change Outs Using Induction Heating Retaining Ring Machining & Insulation Repairs of Elongation, Foreshortening & Top Turn Isolation Main Lead Manufacturing Containment Facilities & Asbestos Abatement Copper Dust Inspections Bore Copper Inspection & Replacement NDE of Wedges, Forging & Rings Hydrogen Seal Inspection Turnkey Collector Ring Services Painting of Forgings Application of Tagging Compounds Turnkey Transportation
  5. 5. Generator Stator Services Conventional and Liquid-Cooled Rewinds Turnkey Disassembly & Assembly New Stator Bars, Including Liquid-Cooled Project Management & Technical Direction Bar Insulation Repair Repair of core iron End Winding Redesign & Installation Re-Wedging & Upgrades, Including TIL- 1197 Tagging Compounds for Core Monitoring Installation of Flux Probes, Buss & Slot Couplers Installation of New RTDs
  6. 6. Electrical Testing & Inspection Services AC & DC Hi Potential Test AC Impedance Tests Digital ELCID Meggar Boroscopic Inspections Pole Balance Drop Calculation of Polarity Indexes DC Leakage Wedge Surveys and Mapping Resistance Testing of RTDs Visual Inspections Capacitance Mapping Retaining Ring Inspections
  7. 7. H.I.T. Skids / Flush & Bake SkidsFor Liquid Cooled Generators Five Skids Tools to Address TIL 1098 Fast Dry Out of Cooling System for Elec. Testing Prep For Vacuum & Pressure Decay TestsFlush & Bake Skids: Flush Stator Cooling System & Bars After Rewind Cures Epoxies & Conforming Materials Reduces Bake Cycle Significantly
  8. 8. High Voltage Bushing RefurbishmentNew or Refurbished High VoltageBushings : Re-manufacture & rebuild nearly all models Refurbishment cost much less than new bushings Provides an opportunity to upgrade bushing components Faster turn-around than waiting for new bushings We maintain a finished inventory of common bushings Porcelain or composite insulators Complete electrical testing Turnkey installation
  9. 9. Rotor Testing & Inspection
  10. 10. Components of a FieldCollector RingsJournalFan RingRetaining RingBodySlotBlockingCoilsCoupling
  11. 11. Components of a Field SlotWedgeCreepageTurnsTurn InsulationSlot ArmorSub Slot Armor
  12. 12. Typical Electrical Field Test on a Generator Rotor  Megohm Test (megger)  Winding Resistance Test  AC Impedance Test  Pole Balance Test  Visual Inspections
  13. 13. Field Testing Megohm Test (megger) Checks Ground Wall Insulation Slot Liners Creepage Blocks and Slot Bottom Covers Retaining Ring Insulation Terminal Stud Insulation Bore Copper Tube Collector Ring Sleeves
  14. 14. Field Winding Resistance TestMeasurement is converted to standard temperature specific to the manufacturer
  15. 15. Field Winding Resistance TestTypical Issues to Identify Lower than Normal Resistance MeansTurn to Turn Shorting is Present Higher than Normal Resistance CouldMean a Few Different Things:  Cracked Conductor  Elongated Conductors
  16. 16. Field TestingAC Impedance Test Checks for Turn to Turn Shorting Rotor Acts as an Inductor whenPassing AC Current Through the Windings The Current Flow is “Choked” orRestricted by the Number of Turns Around the IronCore (Rotor Body)
  17. 17. AC Impedance Test SetVoltage is raised in 10V steps and current is measured at each step. Also, Impedance (Ohms) is calculated
  18. 18. Field Testing Pole Balance Test Only Performed if Access is Available to the Pole to Pole Connector (or Very Close By)  Usually Performed with AC  Voltage Applied as High as Practical-- Usually 100V  Voltage is Measured from Inboard Collector
  19. 19. Field During Rewind
  20. 20. Bore Copper Assembly
  21. 21. Stator Testing
  22. 22. Stator (Armature) Testing Winding Resistance Test Megohm Test (megger) DC Leakage Test DC Hipot RTD Resistance Test RTD Megger Test
  23. 23. Stator Field Testing Winding Resistance Test oMeasured with a Digital Low Resistance Ohm Meter (DLRO) • Also Known as a “Bridge”, “Ductor”, “Micro Ohm Meter” Regardless of Name, All are a 4 Wire Kelvin Bridge Device
  24. 24. Stator Field Testing Megohm Test (megger) Checks Ground Wall Insulation  Taped Insulation on Bars/Coils  Porcelain or Epoxy Insulation on Terminal and Stand-off Bushings  Hoses on Water or Oil Cooled Machines
  25. 25. Stator Field Testing Megohm Test (megger)  Usually Performed at 2500 V or 5000 V for 10 Minutes  All Megger Tests are DC  Achieve a Final Megohm Reading and Polarization Index (PI)  PI = R10 / R1
  26. 26. Stator Field Testing Megohm Test (megger)  Reduced Creepage Paths (Distance to Ground) Can Lead to Low Megohm Readings  Dirty or Contaminated Bushings/Terminals  Insulation Migration (Big Problem in Certain Asphalt-Mica Machines)
  27. 27. Stator Field TestingAEMC ElectronicMegohm Meter
  28. 28. Stator Field Testing DC Leakage Test  A High Voltage Test of the Stator Windings Used to Gain Quantitative and Historical Data as to the Condition of the Insulation  DC Tests in General are Sensitive Indicators of the Presence of Cracks, Fissures, Reduced Creepage Paths, Moisture and Dirt
  29. 29. Stator Field Testing DC Leakage Test  Consists of a Series of Insulation Resistance Measurements Taken at Increasing Voltage Steps on a Scheduled Time Basis  A 10 Minute Preliminary Di-electric Absorption Test Determines the Absorption Ratio of the Insulation (N number)
  30. 30. Stator Field TestingDC LeakageTest Underway
  31. 31. Stator Field Testing DC Leakage Test  Sphere-Gap Voltmeter Is Used to Verify Voltmeter and for Overvoltage Protection  Sphere-Gap Voltmeter (Spheres) Are Set to Arc Over at 10 to 15% Higher Than Max Test Voltage  Set High Enough So That It Does Not Add Significant Leakage Current
  32. 32. Stator Field Testing80 KV DC Hipot, IsolationTransformer and Sphere-GapVoltmeter
  33. 33. Stator Field Testing DC High Potential Test (Hipot)  Final Suitability for Service Test  Substitute for AC Test, Which Requires a Large and Expensive Piece of Equipment  May or May Not Be Required by Insurance Company
  34. 34. Stator Field Testing DC High Potential Test (Hipot)  Often Times Is Performed as the Last Step of a DC Leakage Test  Leakage Value Is Not Important Since Extraneous Leakage Currents Can Be Very High  Surface Tracking  Ionization of Air Near Terminals
  35. 35. Stator Field Testing RTD Testing Resistance Test  Resistance Is Measured Between Each Leg (wire)  Excel Spread Sheets Calculates Temperature  Checked to Insure That All RTDs are Functional
  36. 36. Stator Field Testing RTD Testing Megger Test (Slot RTDs Only)  Resistance to Ground Is Measured at 500 Volts  Checked to Insure That RTDs are Not Capable of Creating Circulating Currents Which Could Result In Localized Heating and Back Feeds into the Meters
  37. 37. Stator PhotosEnd Windingsand Core onLarge WaterCooledGenerator
  38. 38. Stator PhotosStand-OffInsulator
  39. 39. Stator PhotosPTFE Hoseson WaterCooled Stator
  40. 40. Stator PhotosTapeSeparation onAsphalt-MicaBar
  41. 41. Stator PhotosTypical GE RTDPanel
  42. 42. Turbine-Generator Repair Facility• 170, 000 Square Feet• 90 Ton Crane Capacity• Dedicated Blast Cleaning• High Speed Balance Facility (late 2013)
  43. 43. Reverse Engineering: Addressing Critical Needs
  44. 44. Reverse Engineering: Addressing Critical Needs  Focused on Stator Components (Free)  We Come to You  Experienced Staff  State-of-the-Art Equipment  Supported by In-house CAD & Engineering  Digital Material Composition Analysis  Quick Turn Around
  46. 46. QUESTIONS ?