With today being the first day of the holidays we got a lovely extra hour sleep in. We began by dividing the 40 gallon drum into 3 segments. This was a challenging task as we were mainly guessing where the center was based on the 3 even points we marked out. We drew a triangle between all 3 points and then measured the length of the lines. They ended up being 500mm. So we marked 250mm on each line and drew a line from each corner of the triangle to the opposing middle mark. After all of the sides were marked we each cut a segment with a cutting disc as only Gary, Darryl and I were present today. After that we smoothed off the cuts with a finishing disc. Then we faced the problem of how we would hold the barrels together. Damon suggested we bolt them close together so we went with that design only to face the problem of mounting the stator onto the barrels. So we grinded off the welds and will start rewelding the segments onto arms that will connect to the casing.
We started the day by finishing off soldering the cables to the stator and setting up the photovoltaics to charge the batteries. We then came to the hypothesis that by having all of the class' projects connected onto the bus, the bolts/terminals would not be big enough to be permit all of the cables, so Kieran and Gary went to see Bernie (Mechanical Fitter tutor) about modifying bus bars for us. In the end he just gave made new brass connectors for us and they fitted perfectly. We then decided to put a rope in the pulley on the post so that when the time was needed we could erect the vertical shaft turbine. Once that was done Gary rigged together a few diode boards and attempted to build a 3 phase rectifier. For some reason he decided to plug it into the work benches at 400V and blew up 3 of the 8A diodes. After revising his mistake he has successfully created the 3 phase rectifier. When the batteries were fully charged we managed to run the G.T.I. for 8 minutes and 14 seconds which was impressive as we were just using the photovoltaics and today was a very overcast day. After the batteries were discharged, we hooked them back up to the photovoltaics and got the batteries charged and ran the G.T.I. for a second time. This time we lasted 8 minutes and 30 seconds. For the rest of the day we were brain storming on which design to use for our wind turbine.
Today we began by crimping the ends of the photovoltaic cell leads with female crimps and then 2.5mm² TPS with male crimps so that they could easily be connected and disconnected as stripping the cables continuously would not be ideal as we'd eventually run out of cable length. Due to the solar charge controller being still in repair, we had to connect the solar panels straight on to the batteries. The only problem with this was that when the batteries were fully charged they would continue to be charged until disconnected and this could result badly so we had to monitor the amount of voltage the batteries had. We also connected an ammeter between the TPS and the batteries to measure how much amps the cells were producing. The process of charging the batteries with just the photovoltaics was a lengthy one so we headed off to an early lunch. Before leaving we gave feeding the class a test run with the batteries on about 25V but there just wasn't enough charge in the batteries. When we returned, the batteries were sitting just over 26.5V so we had a bit more waiting to do. When they finally reached full charge (28V) we turned on the Inverter, Battery Bank and G.T.I. and we successfully fed the classroom but only for about 2-3 minutes. Due to slack team members, Tutor Andrew Massie prescribed us another grueling task: A vertical wind turbine. The equipment for this from previous years are broken and it's just less time consuming for us to start from scratch. So far we are in the process of rewiring the stator as it is currently rated for 230V and we need to get it to 24VDC. Revised project plan
Photovoltaics test run
Crimped photovoltaic leads.
Insulation taped female to male crimps for added safety (what Chenergy is all about).
Tutor Andrew Massie going for a stroll and our photovoltaics at work.
DC Voltmeter on 30V range. Measuring battery voltages.
DC Ammeter on 25A Range. Measuring input current.
Successfully feeding the classroom/grid.
Starting on the Wind Turbine
Gary sanding off the enamel from the copper.
Darryl preparing the copper for rewiring/soldering.
We started the day by fixing up the hinges on the photovoltaic cell containers as the wood split on it whilst we were putting away the panels yesterday. This was quite time consuming because we were limited on working space as the wooden framing was in the way. During the time we were doing that, Darryl was drilling a hole through to the classroom and fitting some conduit for us to run the cables from the solar panels (outside) to the 24V Bus (inside). To begin we were using 1.5mm² 2C TPS as the solar panels are only 240W at 24V so they would draw no more than 11V (P=VI) and 1.5mm² is rated to 17Amps. However, we didn't put into considering the volt drop and switched it over to 2.5mm² 2C+E TPS. EMF were unable to handle their work load and gave us permission to set up the 2KW inverter and 24VDC Bus. We test run the Grid Tied Inverter from the 24V bus but the batteries were too discharged to show us any positive results so we must wait till we get back the broken Solar Charge Controller so we are able to charge the batteries.
Unscrewing the hinges to be moved to.
Repaired enclosed photovoltaic cells.
Photovoltaic Cells conduit
Neatly mounted conduit for photovoltaic cells running from outside to inside.
The connection between the conduit and classroom.
Kieran pulling TPS through the conduit out into the terminal block.
Conduit coming from outside into classroom.
Neat and tiny conduit going from photovoltaics to the 24V Bus.
Final part of conduit going to the 24V Bus. Doing EMF's dirty work
Reworked 24V bus and used a 16mm² Single core link between the batteries as the 1.5mm² link was not handling the current well and the cable got very warm.
We wall mounted the 2KW inverter as it was the aesthetically pleasing option.
Test running the G.T.I. on 24V Batteries
The agonising minute wait for the G.T.I. to start.
Today was full of it's successes and mishaps. We got the photovoltaic cells churning out 24V and the Grid Tied Inverter and 150VDC Battery bank connected and running. However, during the process of pack up, Jeorge managed to short circuit the load cables, blowing part of the Solar Charge Controller which was a huge mistake. Apart from this blunder, the day went smooth and relatively fast. We can not wait to have everything up and running to feed the classroom.
Safety Hazard Worksheet to sign onto.
Mounting The G.T.I. to the wall.
Unscrewing the front panel to take off the cover.
The back of the touch panel.
The back of the front panel.
Connected Grid Tied Inverter to the switchboard via conduit thanks to Tutor Andrew Massie.
Grid Tied Inverter and 150VDC Battery Bank(Mounted via Gary and Alex) mounted on wall.