14/08/2009 Progress

Electrical Progress

• Calculated that LM338 will fit.
• Re-drew the PCB to include the LM338 (which is huge !)
• Re-drew the PCB with outputs on the 'left' hand side (for easy plugging)
• Purchased LM338 and 2 filter capacitors recommended by Spec sheet.
• Re-drew the PCB to include the filter capacitors.
• Investigated Pre-regulator (instaed of using LM338). These crude circuits waste a lot of power, especially when the difference in voltage is high. There is a "pure" burning of power in transistors, which will need to be heat-sinked.
• Thorough testing (by drawing over) the circuit ... and discovered +42V being applied to the ground pin of the fuel gauge !!! Would have got there anyway, through capacitor. So added diode. Probably not needed (as there is no ground ... just +ives attached to Guage) ... but there is unknown potential inside the device, to stuff it up !
• Discovered fault in PCB software ... pins on the TO-3 LM338 are wrong !!! Very serious fault, corrected in PCB sofware. Whew !!!

Kart Progress

• Pillow block bearings turned up. Excellent ... but heavy !
• Kilovac relay turned up. Excellent ... and light (especially by comparison with the bearings).

Other notes

• Dropped back the hire car, and collected by car after its repair.
• Enormous difference between the two cars. Interestingly ... the smooth (and gutless, and whiny motored) hire car meant I was very passive in traffic. The STI makes you an aggressive driver. The difference is quite dramatic !