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Detachable Chair Spacing Margin of Error question


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#1 evan10s

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Posted 09 March 2016 - 03:35 PM

I was wondering how much error there is in the chair spacing on high speed lifts. I know that the spacing appears to be the same, but I feel like there might be an inch or two of variance that can't be seen.

Also, how much compensation does the lift do to keep the chairs spaced evenly? For example, is there much difference in the way an empty versus a full chair would be handled by the lift in terms of acceleration (because an empty chair would accelerate faster than a full one)?

This post has been edited by Kelly: 05 March 2017 - 07:00 AM


#2 NHskier13

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Posted 09 March 2016 - 04:48 PM

I don't have much technical background on lifts, but a recent example I have ridden was the White Peaks Express at Waterville valley. The chair spacing appears to be done at the bottom, in which there are tires on the ends, but the last 4-5 feet to the turnaround is partly chain ridden- there are sets of three "teeth" that ride around and catch the chairs, usually on point. The top is just a full chain turn around looping back into tires. On that lift at least, the margin of error would only really occur at the top station, anywhere else would entirely rely on the machinery (logically)
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#3 chasl

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Posted 10 March 2016 - 06:22 AM

Chair spacing is dependent on the manufacturer's design, A Doppelmayr will have what is called rough spacing at one end of the lift generally at the loading area, this is a not a given. The rough spacing is used by most only when needed, such as summer maintenance, or if there has been an issue within the chair transfer system. the rough spacing system physically stops a chair for a set amount of impulses, then sends it out of the terminal. Then the stow clutch engages and sends the chair in waiting to the start clutch which holds it for the set amount of impulses then sends it out. this continues until all of your chairs have been rough spaced, then the rough spacing system is shut off. The rough spacing system should only used when you are not loading customers. There has been instances where the rough spacing had to be used during the day and the expressions of the customers from the chairs stopping or miss loads can be fun to watch The impulses (mentioned prior) are received from the impulse sheave in the drive terminal. The impulse sheave is constantly counting impulses while the lift is running and sending the count to the terminals central processing unit of the low volt system.The rough spacing system will put the chair into a position that will allow the lift to run without stopping on an anti collision fault or zone fault. Then,(generally at the unload end of a lift) the system has what is called a fine spacing system, this system is constantly on, when the lift is running (except when the rough spacing system is in operation). this system either slows a chair or speeds it up to keep the chair within a range of around + or - 15 impulses, depending on what is set by the mfg. A chair will not re-space if it is in the tolerance window. The fine spacing happens, after the customer has gotten off the lift and the chair is in the turn around section of the terminal, for obvious reasons. On a Doppelmayr if there is a problem with the fine spacing system, it can be locked out and then it just becomes one of your transfer wheel sets. Things that will cause a chair to exceed the + or - window, can be obstruction in the running rail (ice, dirt, tool) loose belts, low tire pressure or ice on a traction plate. There are other issues that can cause a chair to leave the window of tolerance, but I think you get the idea. There are some systems still running that use the chains to transfer the chair through the terminal, but those numbers dwindle as time goes on.

This post has been edited by chasl: 10 March 2016 - 06:31 AM


#4 lift_electrical

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Posted 10 March 2016 - 08:58 AM

Chasl,

A couple observations based on my experience with Doppelmayr lifts. All the top drive systems I have seen have the fine spacing at the drive and rough spacing at the return. I think this is because the chairs are regulated after the loaded carriers arrive at the top. Not familiar with any bottom drives that fine space at the bottom?

There are impulse sheaves at each end of the lift and these counters are being used for the spacing at each end along with a few other functions.

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#5 chasl

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Posted 10 March 2016 - 10:35 AM

View Postlift_electrical, on 10 March 2016 - 08:58 AM, said:

Chasl,

A couple observations based on my experience with Doppelmayr lifts. All the top drive systems I have seen have the fine spacing at the drive and rough spacing at the return. I think this is because the chairs are regulated after the loaded carriers arrive at the top. Not familiar with any bottom drives that fine space at the bottom?

There are impulse sheaves at each end of the lift and these counters are being used for the spacing at each end along with a few other functions.

Jeff

You would be correct, I just did not want to confuse him anymore than I had. once you have worked with them it seems easy, explaining it makes it sound confusing. From my experience fine spacing is all at the top whether it is a top or bottom drive, but I did not want to rule out another option if it is out there.

#6 liftmech

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Posted 10 March 2016 - 01:08 PM

http://www.skilifts....ble_cadence.htm

An overview Kelly and I wrote up years ago.

Quote

Also, how much compensation does the lift do to keep the chairs spaced evenly? For example, is there much difference in the way an empty versus a full chair would be handled by the lift in terms of acceleration (because an empty chair would accelerate faster than a full one)?

Once the carrier is out of the spacing/cadencing zones, the tire banks accelerate them equally regardless. The tires are locked at their respective speeds since they're all tied together via belts.
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#7 snoloco

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Posted 10 March 2016 - 04:55 PM

The Cabriolet at Mountain Creek sometimes has the rough spacing system at the bottom activated while the lift is open to the public. You hear this "pop" and the car suddenly stops and then starts again. It really startled me the first couple times it happened. Now, I'm pretty used to it. The spacing unit is located right before the acceleration ramp and is after the turnaround.

#8 chasl

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Posted 11 March 2016 - 04:05 AM

View Postsnoloco, on 10 March 2016 - 04:55 PM, said:

The Cabriolet at Mountain Creek sometimes has the rough spacing system at the bottom activated while the lift is open to the public. You hear this "pop" and the car suddenly stops and then starts again. It really startled me the first couple times it happened. Now, I'm pretty used to it. The spacing unit is located right before the acceleration ramp and is after the turnaround.

The Cabriolet has a rough spacing system, only, at the drive and return, there is no fine spacing on the system. Both are normally operational when the the system is running.

This post has been edited by chasl: 11 March 2016 - 04:07 AM


#9 towertop

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Posted 11 March 2016 - 06:07 AM

Yes don't rule too soon... Our drive tension terminal is at the bottom, fine spacing. Our return terminal has core spacing at top. Not too many issues... but if your a number watcher you can gain some valuable information. Such as this one chair is constantly the same number every time and never changes, maybe you have a bad running wheel or every chair is having the same number every lap, maybe something going on with a belt... the most important thing to remember is it all starts with the impulses, they control the system. Ideally you want to see every chair # different every lap witch would indicate all is well in spacing land.

My big question for you is do you start your system immediately or let the lit run a few laps first?
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#10 Aussierob

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Posted 11 March 2016 - 07:57 AM

We turn the spacing system on at start up. You will get some big negative numbers as the lift warms up, but it comes good in a few laps. The peak chair at Whistler is bottom drive/tension/spacing.
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#11 SuperRat

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Posted 11 March 2016 - 12:43 PM

Our three post 1994 Doppelmayrs are fine spacing: Drive, rough spacing: Return and they're all bottom drive lifts. I worked a year at a mountain with an '89 Doppelmayr with bottom drive, bottom rough spacing. You should see how confused people get trying to load a lift when you're doing an emergency rough space. You have to physically hold each group, but anything to keep the lift operating on a Saturday.

If you get some loose belts or soft tires you will see a difference between the acceleration and deceleration of heavily loaded chairs. That's where the spacing errors happen.

#12 2milehi

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Posted 12 March 2016 - 10:37 AM

I can only talk to the older mechanical clutch systems. On a Poma (two clutch system) every chair goes thought the slow then normal clutch at the top terminal on the departure side of the contour. So the margin of error is zero. This system utilizes a friction clutch to transmit power.

On a Doppelmayr system with the mechanical dentured clutches there is a disadvantage in having the clutch cycle for every chair. It will wear the clutches out quicker so the less you use it the less you have to work on it. On one of the Pilz PSS lifts the chair margin of error is +/-15 quick counts or almost +/-4 feet. With our in-house PLC we have a margin of error of +/- 10 feet.

The UNI terminals are able to do about +/- 30 feet of correction. The ET terminals are able to do about +/- 20 feet of correction.

As for how much better an empty chair gets conveyed when compared to a full chair, when everything is correct (belt tension, tire engagement, etc.) you would only see a few counts difference through the accel/decel side in question.

This post has been edited by 2milehi: 12 March 2016 - 10:43 AM

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#13 floridaskier

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Posted 03 March 2017 - 07:30 PM

Was up at Deer Valley today and they were having chair spacing issues all over the place. It was a sunny day with not much wind and temperature in the high 30s (yesterday was about the same weather). Carpenter and Silver Lake both were stopped for a while with a few obvious chairs very close together, Empire had a mechanic pulling chairs around by hand at the bottom, Ruby had a mechanic at the top turnaround, and Quincy shut down for the day at noon, with spacing issues blamed by the operator stationed at the bottom. Never seen any of that as a casual customer before. These are all Garaventa CTEC HSQs, but both Stealth 2s and Stealth 3s with different grip models.

Just bad luck, or are there some kind of weather conditions that would cause a bunch of spacing issues on the same day?

Unrelated note, Homestake (1999 CTEC fixed quad) is out of commission for a couple days with gearbox problems (operator said no evacuation needed). Two high traffic lifts out of commission on a mid-season weekend is a tough day for them.
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#14 CH3skier

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Posted 04 March 2017 - 07:19 PM

View Postfloridaskier, on 03 March 2017 - 07:30 PM, said:

Was up at Deer Valley today and they were having chair spacing issues all over the place. It was a sunny day with not much wind and temperature in the high 30s (yesterday was about the same weather). Carpenter and Silver Lake both were stopped for a while with a few obvious chairs very close together, Empire had a mechanic pulling chairs around by hand at the bottom, Ruby had a mechanic at the top turnaround, and Quincy shut down for the day at noon, with spacing issues blamed by the operator stationed at the bottom. Never seen any of that as a casual customer before. These are all Garaventa CTEC HSQs, but both Stealth 2s and Stealth 3s with different grip models.

Just bad luck, or are there some kind of weather conditions that would cause a bunch of spacing issues on the same day?

Unrelated note, Homestake (1999 CTEC fixed quad) is out of commission for a couple days with gearbox problems (operator said no evacuation needed). Two high traffic lifts out of commission on a mid-season weekend is a tough day for them.

Park City's detach chair spacing is messed up this year. Big spaces between the last chair and chair 1 on most lift and it's getting worse as the year goes on. Orange bubble had about three chair spaces difference today and I hate how they slowed the chairs unloading in the top terminals, makes it harder to unload especially on the six packs. :(

#15 liftmech

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Posted 06 March 2017 - 03:12 PM

View PostCH3skier, on 04 March 2017 - 07:19 PM, said:

Park City's detach chair spacing is messed up this year. Big spaces between the last chair and chair 1 on most lift and it's getting worse as the year goes on. Orange bubble had about three chair spaces difference today and I hate how they slowed the chairs unloading in the top terminals, makes it harder to unload especially on the six packs. :(

You may be seeing the 'end gap' which is a larger space built into the system for a cushion.
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#16 2milehi

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Posted 07 March 2017 - 09:03 AM

If there is more than a two chair gap at the end of the line of a detachable Doppelmayr, something is not right.
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#17 CH3skier

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Posted 10 March 2017 - 08:38 AM

Here is a picture of Orange Bubble. You can see the space between the last chair and chair 1 going up. Most of PC detach chairs are doing this so I would expect there is a reason why.

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#18 snoloco

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Posted 24 March 2017 - 05:21 PM

The Doppelmayr gondola at Mont Tremblant has some cabins spaced differently than the others. Seems to be missing some cabins. I believe they're in the process of completing mid life refurbishments on the cabins and are sending them out a few at a time to get that done.





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