People's lives are at stake!

This is why people here insist you do your own homework/class assignments and learn the lessons for yourself!

http://myfox8.com/2014/06/08/man-in...es-30-floors-in-15-seconds-crashes-into-roof/

The article doesn't state what caused the elevator to 'malfunction' but, I've got to think that if sufficient safeties were in place what is shown wouldn't have happened.

Some people pay for rides like that.............

I agree it is a serious snafu

I have never worked on an elevator before, but one would think that there is a maximum speed they should travel. There is no way that the drive that runs that elevator had a set maximum speed programmed to a safe level. I know that there are other circumstances that made that ride completely dangerous,(moving before the door closed) but a maximum speed would keep something like that from happening even if control of the elevator was lost.

I saw part of the video on the late night news here. I can't help wonder if there's sabotage involved. With a well established system like elevator, the control protocol should be well established and tested which means to me there are more than one safety systems failed or bypassed.

The default safe state should be energy removed from break on the hoist and the guide rail?

I would love to see the final incident report on this.

Not an elevator guy, but I've done a little reading on this because it's potent nightmare fuel! I use elevators every single waking day and wanted to be reassured that such a thing was as unlikely as I suspected.

Elevators have been protected from "free fall" for a long, long time using safeties such as governors that will brake the elevator to it's rails automatically if it exceeds a certain (downward) speed. This type of safety is integral to the design of the system.

What appears to have happened here is a failure of the traction control of the cables themselves which allowed the counterweight to do its job a little too well and pull the car straight up, unchecked. They do make "rope grabbers" which are a braking system specifically designed to stop an elevator car in this condition (or during a power loss) but as I understand it, they are only "required" in new construction and retrofitting such a system is not a high priority for many building owners. I am unfamiliar with Chilean building codes but I imagine that this building didn't have that system.

You will notice that the door opened after it closed first so there are other issues going on.

harryting said:

I saw part of the video on the late night news here. I can't help wonder if there's sabotage involved. With a well established system like elevator, the control protocol should be well established and tested which means to me there are more than one safety systems failed or bypassed.

The default safe state should be energy removed from break on the hoist and the guide rail?

I would love to see the final incident report on this.

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I too wonder about sabotage. I did some brief work on elevator systems for a high rise in San Francisco, there are SEVERAL inherent MECHANICAL safety systems that should have prevented that from taking place, not just electronic. And I too saw that the doors were opening and closing while moving. That too is supposed to have MECHANICAL back-up prevention techniques. So although it is theoretically possible that someone built this elevator system in their cardboard hut with no experience, supervision or inspection, I find that harder to swallow than a very DELIBERATE act of sabotage / terrorism by someone with enough specific experience in elevator safety protocols to have found and disables ALL of them. For motive, think of the possible economic effect this might have from people refusing to get into high-rise elevators, especially in a country like Chile where a significant number of people are already predisposed to distrust government officials.

I wrote a program like this once

Too bad "ElevMike" does not hang out very much anymore.... it would be nice to have his view, I would think there would be so many things that would lock this out

Here are a few old threads connected to elevator logic.

http://www.plctalk.net/qanda/showthread.php?t=15391&highlight=elevator+logic

http://www.plctalk.net/qanda/showthread.php?t=13999&highlight=elevator+logic

http://www.plctalk.net/qanda/showthread.php?t=4256&highlight=elevator+logic

http://www.plctalk.net/qanda/showthread.php?t=19516&highlight=elevator+logic

http://www.plctalk.net/qanda/showthread.php?t=22121&highlight=elevator+logic

geniusintraining said:

I wrote a program like this once

Too bad "ElevMike" does not hang out very much anymore.... it would be nice to have his view, I would think there would be so many things that would lock this out

Click to expand...

It appears he logged on just about 3 weeks ago.

I have had bad dreams very similar to this type of situation. Never an elevator free falling, but always an elevator rocketing up out of control.

curlyandshemp said:

I have had bad dreams very similar to this type of situation. Never an elevator free falling, but always an elevator rocketing up out of control.

Click to expand...

Like Willy Wonka and the Chocolate Factory, but in a bad way...