Friday, 15 July 2011

I set up the xbees today and managed to get them talking wirelessly. I also finished wiring everything but the motor relays on the relay box. I now have the computer talking wirelessly to the micro controller box which controls a relay in the relay box. It all looks a bit messy but once i get everything working i will neaten it up. I was trying to figure out weather to install fuses in the relay boxes to protect against shorts. Depending on where the short is it could burn a lot of the wiring, especially because all they relays are connected in series. I haven't put one in yet but should.

I always assumed that two relays would be enough to drive one motor in forward and reverse, but i found out today that with SPST relays (normal switch) it cant be done with anything less than 4 per motor. This makes sense now but messed up my plans a bit, but i went out and bought some DPST (double pole double pole throw) relays and rob is going to make some motor controllers tomorrow with them. Because the 10A relays draw more than 40mA on their coil (the whole reason i got the sparkfun relay boards with transistors built in) i had to get some smaller relays to use for the trigger.

After installing the two motor controller relays the boxes should be done accept for sensors.

I found out yesterday when testing the pressurisation system for the first time that the nitrous solenoids have a maximum operating pressure quite a bit lower than i hoped for. I knew they were only rated for nitrous pressures (1100 PSI is about the greatest pressure it would see) but it would only open the argon tank up to 1500PSI. Above this the solenoid would get hot and draw way too much current. I wont be operating the engine any higher than this but i was expecting ti to go to at least 3000PSI. I haven't tested the smaller solenoids for the remote vent and fill lines, so its possible they will work at a higher pressure because their plunger is smaller, although the solenoid coil is also smaller. I am close to getting the pluming finished. I thread-taped and tightened about half of the fittings yesterday. I really hope the tanks dont leak when testing them. I had a pressure when first pressure testing them where they leaked, i believe because the orings were not seated correctly. When installing the end caps I used a hydraulic ram and during this process the orings must have gone in in the wrong position. The first time i tested them they leaked slightly, but on the second test i increased the pressure much quicker which must have forced them into the correct position. On subsequent tests incrasing slowly there were no leaks, but you can only increase the pressure so slow with a hydraulic pump because the fluid is incompressible. I am hoping that they wont leak whenI introduce the pressure slowly with gas. I also had a idea to test with compressed air with my compressor to not waste argon. I want to pump alot of solvent through the system to dissolve any oil which might be in there. This will give me a good chance to test the filling procedure.

Anywhoo here is a picture of the electronics boxes. I am thinking i might try a video blog next time because writing is tedious.

No comments:

Post a Comment