Minutes
Semester 1
9-8-09: Team Transformers met for the first time, and learned what their project is. Team members exchanged phone numbers and email addresses, and worked together on the team contract. The meeting came to an end when a meeting time and place was established with the team's faculty advisor, Dr. Hess, and the clients for the project.
9-16-09: Team met with Dr. Hess and clients for the first time. Clients were John Finley and Doug Taylor, from SEL. John and Doug gave a presentation explaining the requirements and deliverables for the project. The team had a list of questions prepared for the clients, which they addressed.
9-17-09: Scoping out the project was the main focus. The project was divided into two main parts--the transformer, and the tap changer. Team listed what needed to be done with both parts by the end of the semester. It was decided that Bryan would come up with the ratings for the transformer to be ordered, while Ben, Darin, and Cory would design and fabricate the tap changer. The main action items were to research different tap changer design ideas and specify ratings for the transformer.
9-18-09: Team met exclusively with Dr. Hess for the first time. Dr. Hess was presented with a general timeline for the first semester. Team explained that ordering the transformer and designing the tap changer would be completed for the first semester, while building the tap changer and putting it together with the transformer would come in the second semester. It was decided that while Ben waits for transformer to be ordered, he can design a control system for the tap changer to be operated automatically. Project development roles were also assigned to individual team members.
9-24-09: Team met briefly to fill out the scope assignment for class.
9-25-09: Team met with Dr. Hess to discuss project progress. Dr. Hess addressed the problem of overheating, and said that thermal issues in the transformer should be carefully examined. He also stated that another important item to look at was the torque required to turn the shaft for the tap changer's hand crank. Team decided that more time should still be spent sketching ideas, and a credit card form from the ME Department needed to be filled out.
10-1-09: Team met briefly to discuss poster for snapshot day. The poster was to be divided into eight main pages that would outline certain aspects of the project. The team then drew up the three general tap changer designs in SolidWorks.
10-2-09: Team met with Dr. Hess and Dr. Beyerlein to discuss snapshot day. Teachers explained to team what needed to be listed in the design specs for the project. It was decided that the specs were the top priority, then use a decision matrix based off of the specs to come up with a final design.
10-8-09: Team met to go over decision matrix for tap changer designs. It was decided to move selection of final design out one week (until the 18th) in order to allow for a little more time to study design cost and feasibility, as well as interview some professionals from ABB and Square-D about tap changer designs that they have come up with. It was discussed that the team needs to find a tap changer off-grid inside Avista somewhere that we can examine and learn from. It was also decided that more research needs to be given to understanding the exact differences between resistive and reactive tap changers, as we have received an opinion from ABB that a reactive tap changer might be too difficult for us (a reactive tap changer is what was asked for by the client).
10-9-09: Team met with Dr. Hess, John Finley, and Normand from SEL to talk about progress of project. Normand gave his insight on the phase-shifting transformer/tap changer, and reevaluated the design specs with the team.
10-14-09: Team made an official conference call with ABB, and talked out loud on speaker phone. Team inquired about appropriate contact forces for the tap changer, and how to properly design the Geneva gear as an energy storage device. ABB provided great information and advice, and thought that a single plane tap changer would be best to use.
10-15-09: Team met to discuss tasks that had been completed, were in progress, and not yet started. It was decided that the team needs overall better documentation and should keep a project notebook. Members discussed certain design aspects, including the pros and cons. Aspects included the effect of the orientation of the 3 tap phases on the Geneva gear system, the tip of the contacts, and the direction of applied contact force.
10-16-09: Team met with Dr. Hess to discuss tap changer design updates. ME's informed Dr. Hess of certain design decisions, mentioned above, and Bryan talked about transformer ratings. It turned out SEL was unsure of how they want the order of the phase shifts. Team also discussed logbooks with Dr. Hess, and then the design review. Dr. Hess stated that he wanted functional drawings at the design review, not just powerpoint presentations with titles of how team did things.
10-20-09: Team met to discuss further design considerations. SEL still hadn't decided on the order of phase change, so team was deciding between single planed or triple planed circular arrangement. Members decided to go over certain components and design decisions, justifying each decision based on easiness and recommendation by professionals. Team discussed the reasoning behind the orientation of the taps and contact forces, the nature of the Geneva gear box, putting resistive bridging on the ends of the contacts, and potentially how to connect the wiring to the contacts. Team also discussed scheduling the design review on Thursday, November 19, at an SEL conference room. Meeting was concluded by laying out a step-by-step process for detailed design, starting with the size of the contacts.
10-23-09: Team met with Dr. Hess and Dr. Beyerlein to discuss current electrical and mechanical decisions. Although Bryan stated that SEL still needed a range of values for the transformer, the wait time would only be 4 or 5 weeks. Bryan said the transformer would be ordered on Nov. 11. It turned out that SEL was still looking for 10 positions on the switch per phase, but wanted to find out from ABB who makes tap changers with the load susceptible to change. ME's reviewed the step-by-step process to Dr.'s Hess and Beyerlein on how to design the tap changer mechanisms. Team then discussed having the design review on Thursday, Nov 19, at an SEL interview room. Dr. Beyerlein suggested showing design decisions on team website. Meeting concluded with team deciding on getting started on a dynamic model the following week.
10-26-09: Team met to get started on a dynamic model. It was discussed that the contacts should be concave outward, so the moving contacts can slide right on in without missing them and oscillating won't be as much of a problem.
10-30-09: Team met with Dr. Hess, Doug Taylor, and John Finley to discuss current updates and decisions on the transformer. Darin first went over certain mechanical design decisions, including the orientation of the tap changer, having resistive bridging at the end of the contacts, how to connect the wirings, and the Geneva gear system. Ben then discussed the dynamic model for the Geneva gear system needed to figure out the size of the spring. Cory then went over a MathCad model explaining how to determine which spring to use for the contact force based off of spacing constraints. Bryan went over current transformer ratings and design decisions. Doug and John then stated that they wanted some sort of stopping device between the 1 degree and 10 degree phases to prevent a huge jump. They also wanted the contacts to be as secure in place as possible, which means having more than a small point contact.
11-2-09: Team met to talk about some more in depth design. Ben had developed more of a dynamic model to predict the oscillation movement of the contact springs, which led to shaping the contact spaces as a sinusoidal shape. Team also discussed how certain parts would be put together, such as connecting the contact arms to the rotating shaft, from the shaft to the Geneva gear box, how the gear system would be put together, how to develop a switching device for going from positive to negative phase angle, and how the electrical contacts would be put into place in the tap changer "shell".
11-9-09: Team met to determine the input/output relationship for the Geneva gear system, as well as the stiffness of springs and bearing selection process.
11-13-09: Team met with Dr. Hess to talk about project. Ben went over the math model, Darin showed the current solid model of the tap changer, and Bryan went over the final transformer specs. Dr. Hess talked about completing the logbook reviews before Thanksgiving break.
11-16-09: Team met to discuss the layout for the design review. Bryan will start off talking about the transformer. Cory will then talk about the initial design specs and lead into certain design decisions. Darin will expand on these decisions while also showing the solid model of the tap changer. Then Ben will go over the math modeling involved with the tap changer. Darin will talk about how certain parts will be machined next semester, and Cory will conclude with an estimated cost of the device.
11-19-09: Design review was held at a conference room at SEL. It went pretty well; Normand, John, and Doug seemed pleased with our progress and the direction we were heading in.
11-30-09: Team met to discuss tasks for the rest of the semester. It was decided that a final report, bill of materials, and final drawing package were needed to conclude the semester. The team also discussed the upcoming snapshot day. Darrin decided he would start on the final report, and Ben and Cory would help convert SolidWorks parts into drawings. Bryan, Ben, and Cory would start working on the poster needed to be shown for snapshot day.
12-7-09: Team met briefly to discuss what needed to be completed for the final report. The parts still needed to be converted to drawings, and a more detailed bill of materials was needed.
Semester 2
1-15-10: Team met for the first time of the semester with new faculty advisor Dr. Donohoe. The team explained the background of the project to Dr. Donohoe, and showed him what had been accomplished so far. He then stated that what he wants in addition to what we have is a schedule of events for this semester, as well as something that ties the mechanical and electrical aspects of the project together. Everyone agreed that faculty/team meetings would be held on Mondays at 4:30, in Dr. Donohoe's office.
1-25-10: Team met with Dr. Donohoe to present a schedule of events for the second semester. One particularly important date that was noted was March 10, which is when the team hopes to have the tap changer assembled by. It was decided that during the next week, the drawing package would be completely finalized and gone over by Jason Cyr, the team's grad student mentor.
1-27-10: Team met to discuss what needed to be done. It was decided that the design of the tap changer shell was high on the priority list, as it is one of the most complicated parts. Also brought up was the shaft with the helix. Bryan stated that the helical groove needs to be reasonably wide to allow for room of the three conducting ribbons. Furthermore, a method for insulating between the ribbons needed to be decided. The need for a cart was brought up; as soon as Bryan talks to Dr. Hobb a reasonably sized cart could be determined and then ordered.
2-1-10: Team met with Dr. Donohoe and Dr. Hobb to talk about progress. Bryan stated that the transformer is underway, hopefully it will be here by March 1. The transformer vender had sent Bryan dimensioned drawings of the transformer that were showed to the teachers. Bryan also brought up the idea of controlling the tap changer using synchrophasors, which could be done if time allows. Meanwhile, the drawing package had been finished, but it was decided that it would be reviewed with Jason Cyr and Russ Porter before the mechanicals take off in the machine shop. Lastly, Bryan and Cory decided they would talk with Greg from the basement of GJ to talk about what type of cart would be best to support the system.
2-3-10: Team met in the morning and talked about the DFMEA. Ben and Cory went over possible tap changer failures. Bryan showed some printed up lab procedures for handling the transformer. It was decided that Bryan would come up with some possible failures for the transformer and possible wiring connection ideas. Darin and Ben would get the drawing package finalized and shown to Jason on Friday. Cory would start the DFMEA on Excel, and go talk to Greg with Bryan about carts.
2-8-10: Team met with Dr. Donohoe, Dr. Hobb, and Dr. Beyerlein. It was stated that certain parts needed to be redone due to the sake of easy machining. Also, since Jason Cyr would be gone this week in Hawaii, the team discussed looking in the machine shop to make sure the right sized tools were available. Dr. Hobb stated that some sort of electrical insulation/isolation was needed in the tap changer, and that's something we would need to look at. Bryan said the transformer was being shipped already, and discussed possible ways of getting in into the basement of BEL when it arrived. Bryan and Cory still needed to get ahold of Greg from the GJ basement to talk about carts, and Darin and Ben would revise the parts to show Russ on Friday.
2-10-10: Team met briefly to talk about part revisions that were made. It was decided the mechanicals would go into the machine shop on Thursday at 3:30 to make sure it had the proper sized tools needed to make the tap changer. Meanwhile, Bryan and Cory would go see Greg to discuss carts.
2-21-10: Team met up with Dr. Donohoe. Dr. Donohoe presented a list of some improvements he'd like to see with the team website. The mechanicals then talked about the progress through the machine shop, presenting two shafts that had been machined. The team was also pleased to announce that the transformers had finally come in. Bryan stated that he needed to finish a physical wiring diagram, then talk to Dr. Law about protection.
2-24-10: Team met briefly, but did not talk much. However, team did sign up for Design Expo day, and got that taken care of.
3-3-10: Team met to talk about what had been going on the past week. Bryan stated that the overall layout for the website had been updated, and he needed some type of schedule, as well as instructions for how we're fabricating our parts for the tap changer. Ben said he'd write up a paragraph explaining how the tap changer works, while Cory said he'd email Bryan on how the parts were being machined. Afterwards, team discussed how big the helical groove on the main shaft should be, and how the 3 wirings should be placed in the groove. Bryan stated he'd talk to Dr. Law about the setup of the groove. In the meantime, the mechanicals would try to prototype an armset from plastic using the 3D printer in the CATIA lab.
3-8-10: Team met with Dr. Donohoe to talk about progress. Dr. Donohoe was shown a copper contact, as well as the plexiglass walls, having just been cut. Bryan stated that he discovered how to ground the tap changer, by running the transformers backwards. He also showed a single-phase diagram. The team also talked about Snapshot Day, and what needed to be prepared. Darin would work on an updated timeline and print off an updated assembly, Bryan would provide a single-phase diagram for the poster, Ben would help assemble items for poster, and Cory would organize a DFMEA and print off a budget for the poster.
3-10-10: Team met to discuss electrical isolation in the tap changer. It was decided that certain components would need to be manufactured from nylon.
3-22-10: Team met with Dr. Donohoe after Spring Break. Everyone stated what they had learned and observed from Snapshot Day. A new drawing package was presented, but needed to be corrected. Team discussed short term machining plans, electrical isolation in the tap changer, and wiring. Bryan stated wiring will be expensive, and also discussed his idea of a wiring box through which the phase shift can be controlled. Ben would correct the drawing package, Cory would do a stress analysis on the plexiglas, Bryan would find out where to order all of the components for the box, and everyone would be hitting it hard in the machine shop.
3-24-10: Team met to talk about progress. The mechanicals discussed bolt sizing for the tap changer shell, as well as ordering material for the Geneva gear. Team also talked more about electrical isolation.
3-29-10: Team met with Dr. Donohoe. Bryan stated that he would be doing testing for the transformer in the GJ power lab since it can handle more current. He would be running more tests to determine the size of the wires we would need to buy. He will develop a MathCad model to show expected power values, then test these values in the lab. The mechanicals discussed how to make the Geneva gear, and what size of stock would need to be bought. Electrical isolation was also brought up again, and the use of plastic legs for the base of the tap changer was discussed.
4-4-10: Team met this night to talk about what needed to be developed in the tap changer. In order to electrically isolate the shaft support plate, it was decided that the base plate would be shortened such that the support plate would be bolted straight into the top of the cart. As for the arm assembly, it was decided a thick ring of nylon would go around the shaft, in which the springs and copper armheads would be placed. This will seriously reduce material and labor. In the meantime, the team would research bevel gears and a bearing to go on the top of the big shaft, as well as look at spare scraps the machine shop has for certain components.
4-12-10: Team met with Dr. Donohoe and Jason Cyr. Ben and Darin stated that some of the parts needed to be resized in Solidworks in order to fit in the recently bought bearings. Bryan said that the team poster should be done as soon as possible. It will need lots of pictures, and possibly a Solidworks model of the tap changer. Unfortunately, a copper connector rod was stolen from the transformer, so the transformer may need to be moved to the basement of BEL. For the senior design demo, Bryan got a license to use one of SEL's relays that will show the phase change occurring in the transformer. The team discussed meeting in the machine shop as often as possible, everyday if they can.