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"The best laid plans of mice and men oft times go astray." I use to think that mechanical design really wasn't that trickey a thing. I now see I was wrong, very wrong. Every mechanical piece I've designed for this car has had at least one problem. A few weeks ago I was taking some measurements under the hood of the Escort, and I realized my controller bracket wouldn't work the way it is.
My background is software engineering. We would make countless revisions of the software we were writing, and it wasn't a problem: it just meant erasing an EPROM, and then burning in a new copy of the code. You can't do mechanical design this way. When you send the design off to the welder, it has to be as close to perfection as is possible.
To further this end, I started making full scale models of my parts out of card board or foamcore. Below is a picture of the finished bracket next to the card board mock up.
The model revealed some shortcomings in my design, especially with regard to the bolt holes for the electric motor. The bracket was not being beefy enough around one motor bolt hole, and one of the gussets was too close to the other bolt hole. I revised the drawing for the bracket and you can see it at Designing a Motor Bracket.
When we had some good weather in early February, I drove the Escort out of the back yard, up to the driveway. If you want to see how I supported the motor without the bracket, here's a picture.
The next problem was getting the bracket fabricated. I'd given the drawings for the bracket to my welder friend back in the end of November. In all that time, he still hadn't made the bracket (Fortunately for me, since I needed to change it). But since he was too busy, I was recomended to another welder by my Dad. It cost double what my welder friend was going to charge me, but it was done in under a week.
In retrospect, the 1/4 plate seems like a bit of overkill. I asked the welder if he could've done it in 1/8 plate. He said yes, but the welding would've warped the 1/8 plate a lot.
The next step was to drill holes where the bracket bolts to the motor and to the inside fender. To do this on the motor, I marked cross-hairs on the edge's of the bolt holes with paint, then I held the bracket in position up to the motor. I carefully removed the bracket so as not to smear the paint, and used the paint marks to mark my drill holes. For the inside fender, I marked the position of the bracket on the fender. Then I held a piece of paper over the metal, and marked where the bolt holes were. I then used the paper as a template on the bracket and marked and drilled the bracket.
Another thought that occured to me, was that while an electric motor has nowhere near the vibration of an ICE motor, there would still be some vibration. To dampen that, I found a sheet of rubber, and cut a piece to go on the bottom of the bracket where it rests on the inside fender.
Next, I need to work on the battery racks that go under the hood. One I call the "Radiator Battery Box" because the batteries it holds go where the radiator use to go. The other I call the "Firewall Battery Box" because it's mounted next the the firewall on the passenger side of the car.
Contactor Relays
Getting Ready for the Final Push
Conversion Index