Sunday, 29 September 2013

Day 4


-Set up the variable speed drive to increase frequency which will increase the speed of the motor to  increase our out put.

-Set up oscillicope to get a reading of our sinewave for our wind turbine.

  Today we've got the variable speed drive set up to improve the water pressure by increasing the frequency. We found 65 hertz worked best without overloading it. We started off getting 14v using the the large hose(20mm) as the down pipe onto the Pelton wheel and at a later stage we decided to replace the big hose with a smaller hose(15mm) allowing us to change the angle point on the Pelton wheel in doing so we managed to find the sweet spot for water to land on the wheel giving us an out put reaching 34v .
  Today it was not very windy so the wind turbine failed to give us an output of 12v. We need a constant 12v for the inverter to change it from dc-ac so we can check its sine wave on the oscilloscope, we hope to do this on a windy day before connecting to the buss.
Day 3

Goals:  Get hydro working at its optimum level.
            Connect wind turbine to busbar
            Solve the issue of stepping 12vDC to 24vDC for the wind output

  To achieve our goals today we need to finish the wind turbine. We decide to use a variac to increase the output. We also need to check the smoothness of the DC output wave by using an oscilloscope, to make sure it will be able to charge the batteries that are our busbar.

wind----> 3phase output ?vAC----> rectify to single phase 12vAC----> step up to 24vAC---> inverter DC output----> busbar

  Today was also the day we managed to spin the pelton wheel for the first time, by using a larger hose and altering the position of the hose input we managed to get 5volts AC. We need an output of 12volts. This was discussed at length and trialed a couple of ideas. A 3phase full wave rectifier was built using diode packs which also increased our output to around 11vDC, which is a step in the right direction. Bring on tomorrow. 


Day Two

A team meeting starts the day with safety and the daily goals being discussed.

Goals for the day - figure out how to open the wind turbine unit
                            - test wind turbines internal working and find faults
                            - have the turbine mounted and running
                            - start assembling hydro project

  We decide to split into two groups of two, with Mitch and Jordon focusing on the hydro project, Kane and Sam working on the wind. This division of work was a key aspect to a successful, productive day resulting in goals getting meet. We still came together at several crucial points of the day, to problem solve as a team to overcome some of the larger issues we encountered.
  Once the wind turbine unit had been cracked open we tested the windings, getting even readings across the three.We opened it up further to see previous modifications- three full wave rectifiers turning the 3 phase AC input into a DC single phase output. Faults were easy to see, the 2.5mm wire connecting the rectifiers had conductors snapped and dodgy terminations, we had a couple of options- use the same rectifiers replacing the wire and improving the connections, adding support to our new terminations by using strengthening putty. Replacing the three rectifiers with one three phase rectifier- at this stage our preferred option- we wanted to upgrade the unit, to improve it and make a worthwhile contribution.  We got our hands on 3 phase full wave rectifyier which answered our dreams. Assembly was straight forward and with our previous experience, it was up the pole- piece of cake.
  Our full attention was then on the hydro project, it was ready for it's test run with time up our sleeve. Our first run produced no water from the hose- our 3phase pump wasnt working- we swapped two phases over- we had water, but not enough pressure to move the pelton wheel.      


Day 1 on the job.


 The morning was used for the overall planning of the project, getting our heads around the different tasks involved, the sequencing of the tasks, our responsibilities involved around the co-ordination of the other teams accessing the busbar, which is an integral part of the class project, with all teams "plugging in". How to address these issues in the most efficient way, was a lengthy discussion between our four team members. 
  The first step after lunch was to assess the wind turbine- which meant assembly and testing. This was enough work to keep us busy  for an afternoon. Our preliminary tests were visual- checking the general condition of the turbine, looking for any obvious faults, it passed. Electrical tests were a little less conclusive, we knew circuit continuity was a problem, from our tests using the Ohm meter.We discussed the idea of disassembling the unit, checking the internal connections- insuring the terminations were ok and everything was fine.  We then tried to spin the blade to get a voltage reading, but then questioned  "how fast does it need to spin to get a reading of voltage produced. Could we do it by hand? Or did it need to be mounted up the pole working under more ideal conditions." We decide to erect the turbine to the top of the pole, under superb conditions to record sketchy voltage readings, fading in and out. Conclusive evidence that our initial prognosis was correct- poor circuit continuity. Slightly disheartened, we removed the turbine from the pole and finished the day knowing we have to backtrack, pulling apart the unit to check internal connections.
how a pelton wheel works

How Wind Turbines Generate Electricity

Sunday, 22 September 2013

Our Team Plan

This is a big project and its always hard to know where to begin when entering uncharted terrain, so we decide the only way to start is by setting up our equipment and looking at what we have, how it's preforming and trying to figure out a way to meet our objectives. 

The major steps involved are:

*Getting each generator tested and running successfully
*Set up busbar batteries
*Set up inverter
*Link our generators and the others to the busbar
*Connect busbar to inverter

Each step will be further broken down according to whats required.  


 Class Goals

*Supply one phase to the 'grid' using a 1.5kW grid-tied inverter and several generation sources.

*Working safely in teams to achieve the goal and documenting the process online using e-portfolios.

E.M.F Conversion Goals

*Generate electricity using Hydroelectric generation,  Horizontal wind turbine.

*Coordination of 24VDC bus batteries and 2kW inverter.

EMF Conversions Project 2013



Our class at Benmore dam

High Voltage Pre Trade

We started this year looking to gain the skills and training to get an apprenticeship in the electrical supply industry. This  is a blog to our biggest and most challenging project, to generate enough electricity to power our classroom with any excess electricity to be sold to the national grid. The class has been split into three teams, with each team having their own responsibilities. Our team is "E.M.F Conversions" and this blog is documenting our journey for trying to achieving our goals.