25 replies to this topic

[skierdude9450]

Yesterday I was at Breckenridge and it was extremely windy. (What else is new ) The detachables were already running at their lowered speed for high winds (I'd estimate about 800 fpm) but they kept slowing down all the time. You would go about one tower before slowing down, and I figured that it couldn't be from people falling, because the mountain was basically vacant, and people don't even fall that much on Quicksilver. It took about 18 minutes to get up the Peak 8 SuperConnect, which normally takes a little over 8!!! There was an anemometer on the tower at the windiest point which was connected to the com line. So I wonder, can an anemometer send a signal to slow down the lift if the wind is too strong? Does it automatically slow the lift down? What is the wind limit for most lifts before they have to slow down or stop? (From the rider's point of view, I'd rather keep on truckin' through the wind gust, rather slow down for it.)

[SuperRat]

skierdude9450, on Dec 24 2007, 09:57 PM, said:

Yesterday I was at Breckenridge and it was extremely windy. (What else is new ) The detachables were already running at their lowered speed for high winds (I'd estimate about 800 fpm) but they kept slowing down all the time. You would go about one tower before slowing down, and I figured that it couldn't be from people falling, because the mountain was basically vacant, and people don't even fall that much on Quicksilver. It took about 18 minutes to get up the Peak 8 SuperConnect, which normally takes a little over 8!!! There was an anemometer on the tower at the windiest point which was connected to the com line. So I wonder, can an anemometer send a signal to slow down the lift if the wind is too strong? Does it automatically slow the lift down? What is the wind limit for most lifts before they have to slow down or stop? (From the rider's point of view, I'd rather keep on truckin' through the wind gust, rather slow down for it.)

Doppelmayr's UNI-GS detachables can have an CPU generated slow down for wind as an option. They are set in the factory to slow down at 60 kph but that parameter can be adjusted.

[102Terry]

SuperRat, on Dec 24 2007, 08:00 PM, said:

Doppelmayr's UNI-GS detachables can have an CPU generated slow down for wind as an option. They are set in the factory to slow down at 60 kph but that parameter can be adjusted.

A wind warning is the first alarm, it just gives an alarm at the Drive station. The next is a wind alarm, this will slow the lift down to 1m/s until the winds drop and the horn reset will clear. The windspeeds are inputed according to each installation, and must stay above that inputed speed for 5 seconds before a warning or alarm will occur.

[skierdude9450]

So what is the wind limit a lift can run at?

[Emax]

On our modified Base10 systems, a wind warning (meaning slow) is issued at a given wind speed and azimuth. A wind stop is issued at a greater wind speed at the same conflicting azimuth.

[liftmech]

skierdude9450, on Dec 24 2007, 07:57 PM, said:

(From the rider's point of view, I'd rather keep on truckin' through the wind gust, rather slow down for it.)

Trust me, you shouldn't. Forward motion combined with an unfavourable wind direction causes more chair swing than you as a rider really want to be subjected to. Add to that the possiblity of a miscapture on a detach, and a slow is always the way to go. The only time I really don't worry about a strong wind is if it is in line with the lift, although a headwind still causes problems for the unloading passengers.
I didn't know one could have the anemometer automatically slow or stop the lift. Makes sense, though- just one more input in the cabinet and a few extra lines of programming.

[spark's]

liftmech, on Dec 25 2007, 02:02 PM, said:

Trust me, you shouldn't. Forward motion combined with an unfavourable wind direction causes more chair swing than you as a rider really want to be subjected to. Add to that the possiblity of a miscapture on a detach, and a slow is always the way to go. The only time I really don't worry about a strong wind is if it is in line with the lift, although a headwind still causes problems for the unloading passengers.
I didn't know one could have the anemometer automatically slow or stop the lift. Makes sense, though- just one more input in the cabinet and a few extra lines of programming.

Great point i was going to say the same thing... We had a strong head wind this past week and it was pushing the cabins threw the departure side... I had 5 or more piggybacks come down the hill... I'll take a cadence chain over a tire turnaround anyday...

[liftmech]

We have a tire turnaround retrofit installed in 2005, the overrunning clutch on the end of the contour had been replaced by an electromagnetic clutch like the original spacer. The idea is to always have a clutch locked on so that the wind won't do what you described. There's not really a wind problem at my top terminal, though- I'll trade you clutches so I can manually respace chairs when I need to.

[LiftTech]

liftmech, on Dec 26 2007, 06:34 PM, said:

We have a tire turnaround retrofit installed in 2005, the overrunning clutch on the end of the contour had been replaced by an electromagnetic clutch like the original spacer. The idea is to always have a clutch locked on so that the wind won't do what you described. There's not really a wind problem at my top terminal, though- I'll trade you clutches so I can manually respace chairs when I need to.

We put in the double clutch’s or one on the second half a few years back on one of our detaches, (the chairs would blow through the spacer with high winds), and we have been going to (not yet) put the Zern from the top on the second half of the return so we would have the entire contour at the return to help with respacing.

[lastchair_44]

liftmech, on Dec 26 2007, 04:34 PM, said:

We have a tire turnaround retrofit installed in 2005, the overrunning clutch on the end of the contour had been replaced by an electromagnetic clutch like the original spacer. The idea is to always have a clutch locked on so that the wind won't do what you described. There's not really a wind problem at my top terminal, though- I'll trade you clutches so I can manually respace chairs when I need to.

John, doesn't the arrival half of your contour freewheel at the return terminal? (you can push carriers ahead, but not hold back) I know it doesn't do you much good when you're at the top, but if you have a good operator down there that has a pretty good idea of what the chairs should look like in station they can help.

[LiftTech]

skierdude9450, on Dec 25 2007, 01:44 PM, said:

So what is the wind limit a lift can run at?

Good question and I would bet no one can answer it, not accurately anyway, it all depends on the lift (many parts to this); the wind direction, the frequency of the gusts (it’s like pushing someone on a swing, push at the right time and it accelerates the motion) and the size of you’re….. Oh forget that part, anyway, as a coworker use to say; you will never know the limits of a machine until you upset it, and to me this means that until you learn the machine you will not know its capability.

[Emax]

It would seem that any given lift would have peculiar sensitivities to wind direction and velocity. The algorithms for appropriate slow-down and for stoppage should both be fairly uncomplicated ones, once these sensitivities are nailed down. I guess that frequency of gusts might also be a useful piece of information.

While such a program loop could provide a very useful automatic function, it might also open a bag of legal worms the first time the algorithm fails to prevent a mishap. Which name will be "on the bottom line"? I'm not sure that I'd want it to be mine.

[Carl]

Riming of the anemometer's cups or blades should be carefully monitored. You Pac NW guys know all about that!

Carl

[RibStaThiok]

[quote name='Carl' date='Dec 27 2007, 07:03 AM' post='69566']
Riming of the anemometer's cups or blades should be carefully monitored. You Pac NW guys know all about that!


You know its time to shut down when the Anemometer blows off

This post has been edited by RibStaThio: 27 December 2007 - 10:02 AM

[Emax]

At Brian Head, we gage wind speed by the angle of deflection of a length of anchor chain. At the five o'clock angle, we slow the lift. At the 3 o'clock angle, we call a wind hold. When the chain breaks, we go home.

[liftmech]

lastchair_44, on Dec 26 2007, 05:16 PM, said:

John, doesn't the arrival half of your contour freewheel at the return terminal? (you can push carriers ahead, but not hold back) I know it doesn't do you much good when you're at the top, but if you have a good operator down there that has a pretty good idea of what the chairs should look like in station they can help.

Mine doesn't, actually. The first gear in the contour is bolted to the last belt sheave and one has to undo all three bolts in order to make the contour freewheel. There's no one-way bearing there.

[liftmech]

RibStaThio, on Dec 27 2007, 11:01 AM, said:

You know its time to shut down when the Anemometer blows off

We actually had that happen last year! The peak recorded gust at the top of Storm King was about five seconds before the station went off line. We found the anemometer hanging by its wire on the mast later, after it had calmed down enough to drive up there.

[Callao]

liftmech, on Dec 25 2007, 03:02 PM, said:

Trust me, you shouldn't. Forward motion combined with an unfavourable wind direction causes more chair swing than you as a rider really want to be subjected to.

I guess I don't understand how a moving carrier is in more danger running fast, than slow (except for the fact that it determines how hard the swung chair hits the tower). Think of Newton: combine two simple velocity vectors (one for wind, and the other for the carrier speed) into one. Thus, the "wind" could be as much as 1,100 fpm faster, or slower. Please explain what you mean when you say the chairs swing more.

Emax, I think I know where that anchor chain used to hang. But I never saw the chain. Didn't you guys put it back up after that one day?

[Allan]

I can use our Paradise chair for an example.. When there is a crosswind and the carriers round the bullwheel at the top station they turn into sails and can come very close to blowing up and hitting the bullwheel. Slowing the lift causes the amount of swing to subside.

See attached pic

Attached File(s)

•  Paradise_hook.jpg (341.83K)
  Number of downloads: 78

[liftmech]

I really can't explain why wind affects a full-speed lift more (I'm a history major- my mistake), but it does. I've seen swinging carriers subside as I slow the lift down. You're right, though, in that speed increases the force when a swinging carrier hits a tower. I guess that's more what my point was, just didn't word it right. Speed increases the possibility of damage as well since a swinging carrier can get caught up in machinery and it takes a full-speed lift longer to stop.