{"id":65360,"date":"2019-11-07T11:41:30","date_gmt":"2019-11-07T16:41:30","guid":{"rendered":"https:\/\/www.mdaturbines.com\/?p=65360"},"modified":"2020-01-30T15:19:14","modified_gmt":"2020-01-30T20:19:14","slug":"generator-flex-lead-replacement","status":"publish","type":"post","link":"https:\/\/www.mdaturbines.com\/resources\/generator-flex-lead-replacement\/","title":{"rendered":"Generator Flex Lead Replacement"},"content":{"rendered":"

Mechanical Dynamics & Analysis (MD&A) experts recently performed a Generator Flex Lead Replacement.\u00a0 At the customer\u2019s request, the Technical Information Letter (TIL) was completed. MD&A provided all the hardware and replaced all flexible leads.<\/p>\n

During the disassembly and replacement of all flexible leads, it was observed that some of the assemblies were too short. The customer arranged for the removal of all asbestos-containing material associated with the flex lead assemblies. This allowed the new flexible leads to be fit and drilled, which created a more uniform bolting configuration with a larger contact surface.<\/p>\n

The installation process also involved properly torquing the stainless-steel bolts, distribution plates, and nuts. Textolite barriers were installed over the flexible leads and were secured in place with glass tape. The final assembly was then insulated using fusible rubber tape, with an outer layer of raw glass tape, varnished and then tag painted.<\/p>\n\n\n\n
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\"Generator
T3 Flex links exposed, found flattened to lengthen<\/figcaption><\/figure><\/td>\n
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\"Generator
Views of T3\u2019s NEW flex links<\/figcaption><\/figure><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Two sets of Generator Stator electrical tests were performed, pre and post flexible lead replacement. The Customer requested that both sets of tests be performed with the unit assembled and under a pressurized carbon dioxide blanket. There were negligible differences between the before and after readings, and all values were consistent with past testing results.<\/p>\n

Additionally, MD&A\u2019s experienced team performed on-site testing and inspections of the Generator Stator and Field<\/a> during a scheduled minor outage, which included visual inspections and a complete series of electrical tests.<\/p>\n

A comprehensive visual inspection of the Generator Stator\u2019s Bushing Box revealed a large crack in T3\u2019s Stand Off Insulator<\/a> (SOI). Once the customer arranged for the removal of the potential asbestos-containing material, the flexible leads, tubular lead, and clamshell were removed, and the old SOI was replaced. The SOI, tubular lead, and clamshell were loosely assembled to ensure proper alignment. All the components were fit checked to be stress-free.<\/p>\n

Once all components were verified to be in proper alignment, the SOI and tubular lead were secured in place. The clamshell was blue checked at the HVB (High Voltage Bushing<\/a>) and tubular lead contact surfaces. Once all component assemblies were verified, the bolting hardware underwent an initial torque. All bolting hardware was torqued a second time, 24 hours later. The assembly was then insulated using fusible rubber tape, with an outer layer of raw glass tape, varnished and then tag painted.<\/p>\n\n\n\n
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\"Generator
Views of SOI T3 (view of the cracked area)<\/figcaption><\/figure><\/td>\n
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\"Generator
Views of T3 SOI replacement process<\/figcaption><\/figure><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

The following series of electrical tests were performed on the Stator while under a pressurized CO2 blanket:<\/p>\n