18 replies to this topic

[RibStaThiok]

Almost every lift tech/attendant/mechanic out there over time comes to recognize something unique about each lift they work on. I'm not talking about the cosmetic stuff but rather.. the way the lift runs. Behaviors, or predictable problems/failures, sounds, and what not. While a ski lift is essentially 2 large wheels, one at top and one at bottom (in most cases) some towers, and the haul rope and carriers... it still goes beyond being a basic mechanical device. It takes on it's on personality. For example, I can ride 2 identical lifts, nearly the same length, same motor rooms, terminals, towers, motors, drives, weights, carriers, and yet when I ride on one, the sound/vibration that travels along the haul rope and is amplified when going across a shiv train will sound completely different from the other. Also the starting and stopping characteristics of them are different too, even though they are using identical componants. In my case, I am citing the Becker Tripple & Porcupine Tripple at Snowbasin, just as an example, since I know them well. both installed in the same year, both by the same manufacturer, roughly the same length, towers, and direction of the rope. both are top terminal drives with bottom non-hydrolic tensioning. Both run roughtly the same amount of hours each year. Yet talk to one of the mechanics who have been working there for many years, he will tell you that one lift is easier to work on and less problematic than the other one, and sounds different from the other one, and does something better than the other one. I've experienced the same thing on YANs Roughly the same year lift, same HP and length, yet one sounds much different, seems to start and stop faster or slower than the other one and has failures or issues that the other one never does.

For those of you who follow what I am saying, name some of the lifts you work on that you've noticed unique things about from a mechanical or even personal perspective.

[SkiDaBird]

It isn't the most detailed thing, but the chairs are not balanced in the terminals on Mineral Basin at Snowbird. The left side of the chair is higher than the right, enough to cause some side to side swing when they exit the terminals. It's more noticeable up top, but happens at the bottom as well.

[Lifty541]

SkiDaBird, that swinging you feel when you enter/exit the terminal might just be the sensation you get as the grip is going under the op rail and detaching/attaching on the haul rope. The op arm is depressed by the rail and causes the carrier to shift slightly from side to side as the result of the mechanism of the grip. I've noticed that you can feel it on all detachables, some more than others. It would surprise me if the swinging was as a result of the carriers not being "balanced," as all terminals are adjusted down to mm's on their rails and conveyers. And the results of adjustments being off would be seen in how the jaws of the grips are wearing, not really by the gross behavior of the carrier as it leaves the terminal. (Although I guess if things were *really* off, that might be the case, but I would think it would manifest in other ways too).

Not really sure if that's what you're referring to since I'm not familiar with the lift you're talking about, but thought I'd mention it.

[SkiDaBird]

You are probably right. This video shows the lift at the end, if you look around the 4:28 mark you can somewhat see what I'm talking about.
https://www.youtube....h?v=--Eoi6D_5hE

[RibStaThiok]

What was an awesome video.. Loved being a part of the ride down on that beautiful powder.. how I miss skiing..

[NHskier13]

I don't know why, but when I see a new expansion or a lift being replaced, I sometimes get a feeling ... no, this shouldn't be a quad a triple is more fitting! and so on

[floridaskier]

SkiDaBird, on 01 November 2015 - 03:33 PM, said:

It isn't the most detailed thing, but the chairs are not balanced in the terminals on Mineral Basin at Snowbird. The left side of the chair is higher than the right, enough to cause some side to side swing when they exit the terminals. It's more noticeable up top, but happens at the bottom as well.

I always thought Empire at DV had the same thing, especially at the bottom terminal. The outside of the seat hangs seems like it's higher. Same model and year built, 1998

[DashHopes]

We have two fixed grip Doppelmayr quads. Talk to any liftie and they tell you that the chair 7 hands twice as hard as the chair 4. We've adjusted the ramp line in different places to find the smoothest handing and the same distance as chair 4 but has never handed as easy as it or had the same out going swing.

[RibStaThiok]

That's exactly what I am talking about, and the purpose of this topic, Dash. Thank you. What lifts/where if you don't mind me asking?

[DashHopes]

Chairs 4 and 7 at Mont Sutton in Quebec.

[skier691]

Our Pink LIft @ Schuss Mtn.... A little sensitive to the extreme cold and usually acts up once a month ��

[RibStaThiok]

What kind of lift? Year/Make

[snoloco]

The Sundown Express and Storm Peak Express at Steamboat are both Doppelmayr HSQ's built in 1992. They are the same exact model and even have the same drive/tension configuration. Sundown has these weird surges in speed near the bottom of the lift, yet when you get to the top, the speed feels more constant. Storm Peak feels as if it runs at a consistent speed throughout the full length of the line. I don't know what causes Sundown's speed surges, but I'm guessing that it is run at a low tension, since it is a very steep lift that is top drive. Sundown is 5400 feet long and serves 1950 vertical feet. Storm Peak is 6800 feet long and serves 2150 vertical feet, so Sundown is considerably steeper. Maybe Storm Peak is run at a higher tension which keeps the speed feeling more constant.

[vons]

I think you are feeling the Drive trying to carry the load, Storm Peak may have a newer drive that is why you don't feel a surge and stall.

This post has been edited by vons: 30 December 2015 - 08:46 AM

[snoloco]

When you get into the top terminal, you'll hear that the drive is running at a constant speed. It only surges at the bottom. Actually Storm Peak was doing the surge and stall today. Both these lifts have 900 hp motors. I'd think that's more than enough for a lifts of their length.

[vons]

The drive will sound constant even if the torque applied varies all lifts do this, BTW Storm peak did the same surging stall sensation as you describe Sundown doing 4-5 years ago when I was last there, Timberline express at copper used to do it to under a full load on the old drive. The length of the lift and the loading of it amplify the sensation but it is the uneven application of torque to the bull wheel that you are feeling.

This post has been edited by vons: 31 December 2015 - 07:19 AM

[ccslider]

I'll bet a nickel that the surging described in the previous posts is due to tower locations relative to carrier spacing. As a carrier approaches a tower, it takes just a little more torque to get it up over the top of the sheave assembly and then a little less as it departs the tower. You can really sense this on a jig back tram and most modern trams adjust the line speed to compensate for the carrier going over the towers to lessen this effect. But of course this is not possible on a chairlift where there are multiple towers and many carriers. So usually the design engineer attempts to place towers so that multiple carriers are not crossing over the sheave assemblies of multiple towers at the same time. But sometimes the engineering doesn't quite get it right or carrier spacing changes and the increased required torque creates the surging sensation.

[Yooper Skier]

I would agree with ccslider. This is most noticeable on our chondola, with its varying loads throughout the line. I've been stationed up at the drive (top) for the past few days and you can really hear it in the gearbox and in the drive, especially after a slow/fast are initiated. It can take up to several minutes until it smooths back out. The return terminal delivers a similar effect. This is only really evident when she's running at full capacity. I do recall the surging sensation on Big Mountain Express at Whitefish. Similar circumstances I'd imagine.

[snoloco]

The Sundown Express stops and slows a lot, much more than Storm Peak, so it had much more pronounced surges. However, all of Steamboat's other detachables didn't have any surges at all. Even the Christie Express which is a beginner lift, therefore stopping the most by far.