2d vs 3d
In Carl Sagan's Cosmos he attempts to give a feel for the fourth dimension by having you imagine yourself as a two dimensional being (I won't name some professions that come to mind) trying to contemplate a third dimension. Your world is a completely flat surface in which you can move forward, backward, left, right, or any combination or fraction of these. Yet there isn't such a thing as up or down. If a three dimensional ball "visited" you it would appear as something beside or in front of you which came from nowhere, grew wider, grew narrower, and then disappeared again. The ball wouldn't have any problems recognizing the 2d world as a bunch of really flat folks, but the 2d world would be left scratching its head (side?), at a loss to describe what it had just witnessed.
In any project like this there comes a time to go from the two dimensional world of paper drawings and suppositions to the 3d world of squeezing things into non-imaginary spaces. Electronic parts are a good example. Take a trip back to my schematic pages and try to envision the 3d world that they will occupy. In the photo above I'm starting to take the first steps. Once my battery boxes are installed and everything else is said and done I'm left with an L shaped space for laying out the parts. Although some of my parts are still relatively 2d and the interconnecting wire looks suspiciously like string, this still gives a good idea of how much space everything takes and how it is wired. Wiring is a tricky subject. Most of the wire going between relays and the controller will be a heavy gauge (2/0), about as thick as a roll of lifesavers. This kind of electronics also benefits from keeping the wire short between the motor, contactors, and controller. What I haven't shown in the photo, nor figured out in my head yet, are which wires to run through holes in the board. Remember, the motor and one of the battery boxes will be below this board.
The photo also shows rough representations of the motor, 144v battery pack, and 12v battery. The idea is to know where the wires are coming onto and leaving the board, where the high voltage sections are, and where the other control wiring and fuses are going to live. I'm guessing about the size of the fuse blocks and wiring terminal strip and there are at least two small 12 volt relays (the little black cube by the potbox) being used.
This isn't the last word with this layout. I'm still trying out different things and there may be a part or two I've overlooked. We'll revisit this again.
© Copyright 1995-2002 Jerry Halstead