Tom noted: “From back of first page: ‘No part of this publication made be copied or reproduced...or be made available on the internet...’ "
It’s hard for me to have respect for or follow specifications by agencies that do not allow reasonable copying or reproducing their specs. I’m not an open-source devotee, but c’mon----how on earth do they expect respect and adherence to rules that aren’t freely made available?
Use good engineering and common sense folks. Go through the numbers, follow examples and be conservative, and definitely bounce your ideas off a friend or folks on this list. Ridiculous things get done and justified in the name of proper design sometimes. I’m reminded of a guy who recently purchased an electric car built in 1913. He decided that he didn’t like the wiring and “needed” to rewire the entire car---likely this didn’t actually need to be done. Much of the decision was based on his perception that the wire gauge was too small (as if engineers didn’t design the car in 1913?). When he purchased new batteries, thinking he needed more speed and range, he upped the car’s voltage from 84v to 96v. And to top it off, he stated that eventually he would use 700ah industrial batteries! I assured him that he did not need 14-hours or more range with a 1913 tiller-steered 20mph car and definitely didn’t want to double the weight of the car, risking major catastrophe. Still, assured he was right, he purchased brand new custom-made lead-acid 225ah flooded batteries with battery posts located “exactly where” he wanted them “to minimize the wiring length between batteries”. Huh? Was that really necessary? No! Despite pointing out to him that the average currents he would see would be less than 50-amps and that the loss with 1/0 or smaller gauge wiring would not justify extreme measures in this area he still justified a serious overly conservative design:
“…ultra flex 2ot welding cable, this cable is made up of multiple strands of #29 wire instead of the normal #25 of regular welding cable. I’m also using 3/8th stainless cap screws, stainless washers and nuts. I am crimping the lugs to the wire then soldering with 95/5 solder and nokrode soldering paste. Then dipping the crimped/soldered lug in to lacquer thinner to remove any residue. I will then paint my lug/cable connection with liquid rubberized coating then heat shrink over that. Most of my inner battery connections will be 6inches or less.”
He prided himself with maintaining the original car as “barn fresh”, yet decided 1913 engineering wasn’t sound when it came to its electrical system. And though he didn’t trust the electrical engineering, he somehow trusted that the chassis and body could handle 14% higher speed and greater weight.
Another similar case: A 1921 electric car was purchased by a veteran professional engineer 3 years ago who has written and published over 50 engineering volumes, most on electrical and engineering standards and codes. Well, within a month of his purchasing the car, he contacted me and informed me that he didn’t like the wiring and ripped it all out. But since he didn’t have a wiring diagram, he wanted me to help him with that…worse, he couldn’t figure out how to disconnect the wires from the mechanical drum controller and so, he cut all 12 of them and installed in-line connectors in each!!! What a waste. It turns out that he didn’t realize that the connectors on this 1919-era General Electric controller used a long conical brass connector of relatively high surface area---much like you see with conical battery posts, only inverse (controller had the female part and the wires each had a male cone end). Anyway, aside from having to be mechanically tapped by a small hammer to get it to release, it’s an awesome connector. So this industry expert on regulations and standards decides his whole antique car needed modern wiring but didn’t take the time to inspect, let alone appreciate anything done by the original GE and electric vehicle engineers. The result looks fine, but could have been a disaster had I not been able to guide him in rewiring the controller.
As an engineer, I continue to be astounded by the tendency of engineers to decide that prior work was wrong and they can do it better without studying and appreciating the underlying reasons for why something was designed the way it was. This includes wanting to know the underlying reasons for any ‘specs’ or codes that should be followed.
Apologies for the ramble-
-Myles Twete, Portland, Or.
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