Kraft Werks originally estimated six to eight weeks on repairs for our fluid drive coupling – but they were able to complete the work faster than expected. We shipped the rotating assembly to Kraft Werks on June 7th and the housing to them on June 20th. They completed all work to the rotating assembly, completely assembled the fluid drive coupling and shipped it back to us on June 30th.
THE SITUATION: On June 3, 2023 we experienced a high vibration on our #1 ID Fan Fluid Drive Coupling. I reached out to Mitch Hamilton with Energy Products and Solutions Inc. and he had Paul give me a call. Paul and I discussed the issues that we were experiencing with our fluid drive coupling and gave us some ideas to try before removing the cover. First, he told us that we need to verify the drive is bolted securely to the sole plates and that the sole plates are secure to the foundation. Finding no issues there, he recommended that we next get inside the drive to do a visual survey. After pulling the cover to look inside, we found several pieces of metal inside the coupling. We decided at this time to pull the rotating assembly out of the housing and send it to Kraft Werks. We shipped the rotating assembly out on June 7, 2023 and it arrived at Kraft Werks on June 8, 2023.
COMMUNICATION: Kraft Werks provided us with a technical advisor during our installation and startup process. They shared daily updates via email and phone along with photos to keep us apprised of the progress.
ACTION: Four days after the rotating assembly arrived at Kraft Werks, Michael informed us that the rotating assembly was fully dissembled and cleaning had begun. Once cleaned, parts would be NDT’d to ensure no further damage.
The next day, they started cutting the vanes out of the impeller. The runner and shafts were inspected. The runner required machining to finish inspections. The shafts passed inspection and were being shipped to the chrome and grind vendor the next morning. They noted there would be an expedite fee for the chrome and grind and that the quote would be updated once finalized.
By June 14, the impeller and runner were ready for machining. The shafts were delivered to the chrome and grind vendor. The weld fixture was located and repairs/modifications were in process. Engineering was modeling the replacement vanes and creating burn programs and a plate had been ordered for the vanes.
The following week, Michael provided us with an optimistic update:
- The runner repair would be finished the next morning. It would head to balance right after.
- The output shaft was finished with chrome and grind and would be picked up the next morning.
- The input shaft would be finished with chrome and grind on Friday.
- The impeller was machined, cleanup, ground and prepped for welding.
- The modifications to the welding fixture would be complete that evening. Paul would help align the fixture and train the welder.
- The vane welding on the impeller was scheduled to begin Friday and finish over the weekend.
- Stress relief would take place Monday morning followed by cleanup machining in the afternoon.
- If all goes well, they would balance on Tuesday – Wednesday with final assembly on Thursday.
By June 30th, the fluid drive coupling was loaded on the truck and being shipped back to Big Rivers Electric. Kraft Werks allowed us to come on site and watch their process on our unit and also gave us a shop tour. They shared fluid drive growth information ahead of receiving the unit to help with installation as well: the 580, with a 67” centerline height is expected to grow 0.026 inches if aligned at an ambient temperature of 70°F. This assumes in operation the oil from the heat exchanger is returning at 135° F and the oil in the housing sump will be higher than that. The fluid drive should be aligned to the drive and driven equipment lower by this amount less any growth seen in the either the drive or driven equipment.
EXPEDITIOUS WORK: The team at Kraft Werks worked hard and was dedicated to getting our fluid drive coupling repaired in an expedited manner. They originally estimated 6 to 8 weeks on repairs. However, they were able to complete the work faster than expected. We shipped the rotating assembly to Kraft Werks on June 7, 2023 and they received it on June 8, 2023. We shipped the housing to them on June 20, 2023 and they received it on June 21, 2023. Kraft Werks completed all work to the rotating assembly, completely assembled the fluid drive coupling, and shipped it back to us on June 30, 2023 – just 23 days!