Rodents like wiring.

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warmstrong1955
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Re: Rodents like wiring.

Post by warmstrong1955 » Fri Nov 01, 2019 9:14 am

jcfx wrote:
Thu Oct 31, 2019 11:11 pm
The wiring difference is night and day, nicely done !
I believe you when you say that the NT100 wiring took more than 70 hours,
btw who makes the NT100 you did the work on ? Googling returns those little
Nissan vans you see tooling around in Japan.
It’s made by Normet, and manufactured in Finland.
What is interesting, and completely crazy, as designed and built, every device, whether it be a light or the horn, has a home run ground wire to the inside of the cab.
The engine ECM....sure, but each and every light, and every electrical component? Why.
We gave it a ‘haircut’.
:)
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warmstrong1955
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Re: Rodents like wiring.

Post by warmstrong1955 » Fri Nov 01, 2019 1:26 pm

I couldn't find any pics of that particular truck when it was done.

But here's a NT-100 Remix Truck.
NT-100 Remix.jpg
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Harold_V
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Re: Rodents like wiring.

Post by Harold_V » Fri Nov 01, 2019 3:34 pm

warmstrong1955 wrote:
Fri Nov 01, 2019 9:14 am
The engine ECM....sure, but each and every light, and every electrical component? Why.
Most likely to guarantee operation (reliability). Redundancy is one approach. Boeing would have benefitted by that concept with their Max.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

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warmstrong1955
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Re: Rodents like wiring.

Post by warmstrong1955 » Fri Nov 01, 2019 3:52 pm

Harold_V wrote:
Fri Nov 01, 2019 3:34 pm
warmstrong1955 wrote:
Fri Nov 01, 2019 9:14 am
The engine ECM....sure, but each and every light, and every electrical component? Why.
Most likely to guarantee operation (reliability). Redundancy is one approach. Boeing would have benefitted by that concept with their Max.

H

I can assure you, after maintaining Normets, the many models they produced, for about 30 years, that reliability may have been the criteria, but they failed.
And, redundancy is not what they did.
On a 'normal' machine, you lose one wire to the left rear light, and you have no light. With a Normet, you lose either one of two wires to that same light, which traverse the total length of the vehicle, and you have no light.
Electrical problems are on the top of the list of downtime on these units.
And, the older they get, the less reliable they become. It just gets progressively worse.
Changing a damaged ROPS cab, which is quite common, is crazy expensive in labor, only for the mass of wires that have to be R&R'd.
They are good vehicles. They could be great, if they would just learn the rule of KISS.

Other manufacturers do it differently, and are in no way less safe, but they are more reliable electrically.
Today's solutions are tomorrow's problems.

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NP317
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Re: Rodents like wiring.

Post by NP317 » Fri Nov 01, 2019 8:12 pm

Harold_V wrote:
Fri Nov 01, 2019 3:34 pm

Most likely to guarantee operation (reliability). Redundancy is one approach. Boeing would have benefitted by that concept with their Max.
Boeing designs: You mean like the original redundant system designed by engineers and eliminated by the financial team on the commercial 737 Max?
The original system is installed on the military version of the 737. It works.
Criminal negligence in my mind.
RussN

Harold_V
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Re: Rodents like wiring.

Post by Harold_V » Sat Nov 02, 2019 1:38 am

NP317 wrote:
Fri Nov 01, 2019 8:12 pm
Harold_V wrote:
Fri Nov 01, 2019 3:34 pm

Most likely to guarantee operation (reliability). Redundancy is one approach. Boeing would have benefitted by that concept with their Max.
Boeing designs: You mean like the original redundant system designed by engineers and eliminated by the financial team on the commercial 737 Max?
The original system is installed on the military version of the 737. It works.
Criminal negligence in my mind.
RussN
Wow! I'd not heard that. Doesn't sound too good.

One thing I have heard is that the airplanes are sold with many features being options. If the one that failed is one of the options, it's strange that the reliability was compromised by not including more than one sensor, which I understand was the problem. Guess we won't know the real deal on this one for quite some time.

In regards to the home run grounds we were discussing, one of the benefits is that it's harder to lose everything. If common ground is, somehow, interrupted, everything would shut down. I can only assume that the intention of the engineers was to avoid such a thing. Better to lose one feature than all of them. :wink:

H
Wise people talk because they have something to say. Fools talk because they have to say something.

TomB
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Re: Rodents like wiring.

Post by TomB » Sat Nov 02, 2019 8:35 am

I worked for Lockheed Martin for 28 years specifically in the area of flight avionics and prior to that for IBM's Federal Systems Division focused on flight avionics for 29 years. Much of my work was relative to the E3-AWACS and other military planes so I was very much involved in joint projects with Boeing even to the point where I recognize some of the Boeing names in the news. Further my son has followed in my footsteps and is now considered a expert in Fault Tolerant computing for planes and helicopters. Every project I was ever involved with seemed to require an expensive FMECA (Failure Mode and Effects Criticality Analysis.) Specialists in that art would figuratively take the design apart and one by one select all the components; hypothesize that if it or its external input failed, then ask what effect would it have on the rest of the system. Obviously one of the things being searched for was the notorious "Single Point of Failures" that would propagate their effect to the whole airplane. Every one of those potential faults had to be addressed very seriously. In this case the petot tube that failed was not part of the MCAS system they added but it was a driver, an input to MCAS, so analyzing the effect of its failure would have been a normal part of the FMECA. Just saying the MCAS would not fail, or that pilots would instantly bypass it due to adrenaline induced panic was not an acceptable step in the analysis. Yet that seems to be what the Boeing Executives did.

As noted, and according to my son, the system is used without a problem on other airplanes, but he also noted that on the other platform he was familiar with, multiple petot tubes were used for input to multiple MCAS's. Redundancy like that is the normal fix for a critical single point of failures. The specific feature that Boeing made an option was an indicator that showed MCAS was acting. Not have that feature meant that the cockpit crew was not made aware of what was causing the nose to dive. As such they did not have a hint as to what to turn off to fix the problem. The indicator had no part in causing the failure but not having it would have increased the criticality of the failure in the petot tube.

People's failure to follow well established processes when that failure leads to deaths should have consequences. Whether that consequence should be the death of the company or the criminal conviction of the responsible employees is in my mind undecided.

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NP317
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Re: Rodents like wiring.

Post by NP317 » Sat Nov 02, 2019 10:24 am

TomB;
Thanks for your clear input. The Boeing Engineers I know told me similar information.
They made the correct designs (which are flying in the military 737s) but someone decided to "save money" on the commercial side.

If a single person made the damaging decision against recommendations and standard design protocols, I think they should have to pay a price.
Really a sad situation, for lives lost, and major interruptions to our transportation system. Not to mention Boeing's business.

My brother was a military pilot and later a commercial pilot for American Airlines. He managed their 757/767 pilot training program for man years.
He used to tell me he would never fly an Airbus product because their fly-by-wire control system could interfere with the pilot's inputs, to the detriment of aircraft safety. There were Airbus crashes caused by this very issue. And now Boeing's mess with the same problem. Where is historic memory? Sad.
And yes, this relates to "Rodents like wiring" ... Ironic connections.

I like to build and operate steam machines.
RussN

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warmstrong1955
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Re: Rodents like wiring.

Post by warmstrong1955 » Sat Nov 02, 2019 11:14 am

Harold_V wrote:
Sat Nov 02, 2019 1:38 am
In regards to the home run grounds we were discussing, one of the benefits is that it's harder to lose everything. If common ground is, somehow, interrupted, everything would shut down. I can only assume that the intention of the engineers was to avoid such a thing. Better to lose one feature than all of them. :wink:

H
When an engineer designs anything, he has to design to the environment, and to say that the underground mining environment is harsh, is a major understatement, and where the phrase "well duh!" came from.
;)

Generally speaking, besides being dark, you have equipment running around in confined areas, and it inevitably is bouncing off solid rock here & there. They drive through muck, water, over rocks and big rocks, and mud, to a point, where you can no longer tell what color they were. Miners & mechanics climb all over it, an although most are not meant to be work platforms, they are used for one, inevitably causing them to get rocks bounced off all over them. (Barring down loose of the top of a machine is common.)
Most mines are wet, some, extremely wet where it rains all the time, and many make Miami seem like the Mojave. Add to that, that many are mining sulfide deposits. Now, you have acidic water. You can watch copper wires turn green, and get fuzzy.
A lot of mines are hot, including extremely hot. That doesn't help a bit.
Some are cold, and to keep the mine water supply from freezing, they add salt to the water. Enter another problem.

So, basically, what makes sense and works on your Buick, Is not necessarily going to work on an UG mine vehicle, nor be a benefit.
Most electrical failures, are at terminations, and also, wires, so on UG equipment, if you add a home ground run to the real lights, you have just doubled the points and area of failures. You have also added to the complexity of the system, making it harder to troubleshoot. Some of those wires are in places a body can't get to.
I have pulled out wires on equipment, that had more butt-splices from repairs, than wire. Any UG mechanic that has been around a year or two, will tell you the same thing. Plugs, are routinely wired around, as the plug and/or sockets in them have failed.

Underground Mining Equipment is the most abused equipment on the planet.....other than a Humvee with an RPG coming at it.
This changes the design criteria, and again, what would be a benefit on a Yawn Deer, or even a 994 or other surface machine, is the opposite on most machines heading under the earth.

:)
Bill
Today's solutions are tomorrow's problems.

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