VFD run amuck?
Keith Cress
kcress -
Keith Cress
kcress -
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VFD in the news?
- Thread starter itsmoked
- Start date
- Moderator
- #2
Old school DOL with fuses Keith. The escalator was overloaded and blew a fuse. The weight of bodies cause the motor to turn backwards and it took off single phasing in reverse.
That's my story and I'm sticking to it. GRIN
Bill
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"Why not the best?"
Jimmy Carter
That's my story and I'm sticking to it. GRIN
Bill
--------------------
"Why not the best?"
Jimmy Carter
- Thread starter
- #3
VFDs on escalators is pretty much a waste, they run at a constant speed. They do use a lot of soft starters in that industry though because of energy savings potential (Nola circuit), however Bill's theory would not work for that because the failure mode is a shorted pole. But most new escalators in transit stations like that are reversing starters so that they can configure the direction of the escalator for traffic flow and manitenance, and it's done with manual switch control of the reversing contactors. It's much more likely that someone just screwed up (big time) and flipped a switch when they shouldn't have.
"Will work for salami"
"Will work for salami"
- Moderator
- #5
- Thread starter
- #6
Well.. I could agree to a lot of possibilities but Jeff's "flipped switch"? Not a chance. I think catching a bus to Hawaii would be more likely than some guy - during mall hours - flipping a switch then leaving it flipped for an extended time during all the pandemonium and screaming.
Keith Cress
kcress -
Keith Cress
kcress -
Might have been one of those "Yo, Tony. Get a load a dis on da security monitor, it's gonna be funny...". (best New Jersey accent I could muster on a keyboard)
My remote internet connection (hotel in La$ Vega$) is too slow now to be able to watch this again, but IIRC at the end doesn't it resume running in the correct direction? How is that going to happen with a blown fuse?
"Will work for salami"
My remote internet connection (hotel in La$ Vega$) is too slow now to be able to watch this again, but IIRC at the end doesn't it resume running in the correct direction? How is that going to happen with a blown fuse?
"Will work for salami"
Skogsgurra
Electrical
Testing my game theory, Jeff?
Gunnar Englund
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Half full - Half empty? I don't mind. It's what in it that counts.
Gunnar Englund
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Half full - Half empty? I don't mind. It's what in it that counts.
Nothing left to test with Gunnar. I arrived, passed through the security gate at the airport, then they stopped me, attached vacuum hoses to my pockets and extracted all valuables immediately upon entry. It just gets it over with faster now.
I like the efficiency, that way I can get to my business right away with no further distractions. I'm here to help negotiate a huge MV drives and a huge LV Motor Control Center project for a power plant. Hoover dam no longer can cut the mustard for supplying the flashing lights and signs now I guess.
"Will work for salami"
I like the efficiency, that way I can get to my business right away with no further distractions. I'm here to help negotiate a huge MV drives and a huge LV Motor Control Center project for a power plant. Hoover dam no longer can cut the mustard for supplying the flashing lights and signs now I guess.
"Will work for salami"
- Thread starter
- #10
Las Vegas? Jeff don't try to augment your salary at the tables, your wife won't like having to re-make the "We'll take sausage for work" sign.
Don't confuse LV for Low Voltage.
I don't think the escalator starts going the right direction. It just looks that way because the camera is riding on the down escalator. When the crazy one stops it looks like it's moving forward.
Keith Cress
kcress -
Don't confuse LV for Low Voltage.
I don't think the escalator starts going the right direction. It just looks that way because the camera is riding on the down escalator. When the crazy one stops it looks like it's moving forward.
Keith Cress
kcress -
Skogsgurra
Electrical
Wish I were there, Jeff!
I have modified my gaming theory and I now know how to get all the way to the tables without lose it all before getting there. What happens at the table is quite another thing.
Gunnar Englund
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
I have modified my gaming theory and I now know how to get all the way to the tables without lose it all before getting there. What happens at the table is quite another thing.
Gunnar Englund
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
I take it that part of the world doesn't use the escalators I've seen at some S-Bahn stations in Germany - Fitted with a floor pad in the approach area at either end, they auto shut-down during quiet spells, then start in whichever direction is needed to move away from the floor pad that gets stepped on first.
I can see how a fault on that sort of system might allow it to do an undemanded reverse.
A.
I can see how a fault on that sort of system might allow it to do an undemanded reverse.
A.
Zeusfaber,
I was involved in a failed experiment a few years ago with an aftermarket escalator control mfr on a project like that where we used a laser scanner looking for feet aproaching the escalator to only turn it on when someone came near. The failure was, when people saw that the escalator was not moving, or perceived that it moved unexpectedly as they aproached, they would not get on it! They tried putting up signs explaining it, nobody read them. Getting on an escalator has become so habituated for us that we don't think about it much, so anything out of the ordinary looks like a red flag. It will take a long tome for that to be accepted.
"Will work for salami"
I was involved in a failed experiment a few years ago with an aftermarket escalator control mfr on a project like that where we used a laser scanner looking for feet aproaching the escalator to only turn it on when someone came near. The failure was, when people saw that the escalator was not moving, or perceived that it moved unexpectedly as they aproached, they would not get on it! They tried putting up signs explaining it, nobody read them. Getting on an escalator has become so habituated for us that we don't think about it much, so anything out of the ordinary looks like a red flag. It will take a long tome for that to be accepted.
"Will work for salami"
It stopped at the end because the Police officer at the bottom pressed the "stop" button. (A few seconds after he probably pressed the "reverse" button and started laughing)
And wow.. Some of those peoples faces seemed like their world was going to end that second.. Its just an escalator people.. There is no "HOT LAVA" at the bottom.
And wow.. Some of those peoples faces seemed like their world was going to end that second.. Its just an escalator people.. There is no "HOT LAVA" at the bottom.
- Thread starter
- #15
I'm pretty surprised the front people didn't just sprint up the escalator. You can traverse stairs faster than an escalator. Hasn't everyone gone down the up or up the down escalator before? I still do if I can be sure no one will get on before I'd make it to the other end.
It's sad to see people just kind of freak out instead of acting in some logical manner.
Keith Cress
kcress -
It's sad to see people just kind of freak out instead of acting in some logical manner.
Keith Cress
kcress -
In had an elevator do that, I worked at a hospital for a while, the nurses thought it would be fun to take the kids for a ride and packed it full.
It was a simple odd elevator 3 phase motor without a phase reversal relay.
Tried to start, blew a phase then started in the wrong direction ending up below the ground floor.
No harm done.
It was a simple odd elevator 3 phase motor without a phase reversal relay.
Tried to start, blew a phase then started in the wrong direction ending up below the ground floor.
No harm done.
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