How a detachable works

[uphillklimber]

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[bdfreetuna]

Interesting. Thanks for taking the time for pics and post.

 

[Newpylong]

Jordan Bowl?

 

[Glenn]

Very cool. A few years back, another AZ member and I got an inside tour of the Canyon lift at Mt. Snow. To see it in action was really cool. It's some very impressive engineering.

 

[Newpylong]

It really opens your eyes and makes it pretty clear why Detachables aren't the right fit, or financially viable for many applications. The last time I spoked with Poma they were recommending the entire terminals be rebuilt after x amounts of hours. That's all of the wheels, pullies, etc, and the sum was a fairly substantial fraction of the original installation cost.

 

[xlr8r]

Very cool, never quite understood how all the acceleration or deceleration tires were geared until this thread. The whole detachable system, while very complex with a lot of moving pieces, also at the same time beautifully simple imo

 

[Newpylong]

Most HSQ's primary electric drive is around 800 HP so convert that to kWh using 3 Phase 480V then multiple it by their electric supply rate then double it for the distribution charge (as it is Commercial) and you should get a rough number. the detachable mechanism I believe runs off a secondary drive as well.

 

[machski]

Newpylong, as I was looking around inside the wheelhouse, it is pretty much a big shed, despite the fancy plexiglass and steel panels. The wheel system is the whole purpose. I can see a ton of fan belts, wheels and bearings in there, all under stress. It becomes easy to see why it needs occasional rebuilding, and it is not surprising that rebuilding it is such a high percentage of the original cost. Outside of the enclosure, all the expense is in the wheels, bearings and fan belts.

I have seen a pile of those tires at the River in one of the storage lots, enough to fill a decent sized dump truck. I'm sure there is considerable expense in maintaining these detachables. I'd love to learn how much energy it takes to run one on an hourly basis.

The storage lot with the tires could be the old tires. Detach cadence tires can be pneumatic or a solid, non air tire. SR originally used the pneumatics but switched over a couple years ago (when a tire went flat the lift would go down until they changed it out or pumped it up) and now they don't have flat tires issues. I have heard though that the non-air tires do have a bigger issue with slippage in icy conditions than their pneumatic counterparts.

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[mbedle]

Newpylong, as I was looking around inside the wheelhouse, it is pretty much a big shed, despite the fancy plexiglass and steel panels. The wheel system is the whole purpose. I can see a ton of fan belts, wheels and bearings in there, all under stress. It becomes easy to see why it needs occasional rebuilding, and it is not surprising that rebuilding it is such a high percentage of the original cost. Outside of the enclosure, all the expense is in the wheels, bearings and fan belts.

I have seen a pile of those tires at the River in one of the storage lots, enough to fill a decent sized dump truck. I'm sure there is considerable expense in maintaining these detachables. I'd love to learn how much energy it takes to run one on an hourly basis.

I am not sure that i agree with the statement that the conveyor systems on a detachable are under a tremendous amount of stress, nor a high cost maintenance item. isn't it basically just a bunch of tires pushing the chairs around a metal bar. The cost for the belts and tires should be fairly low and how often do you think these tires need to be replaced? By far, I would say that anything associated with the drivetrain and the bull wheel are the most expensive maintenance items. Last year I watch them drop the bull wheel on the overeasy gondola to replace a bearing, it took a long time and a lot of labor. The amount of effort to pull apart a 600 - 800 HP motor to replace a bearing has to be significant.

 

[Newpylong]

Newpylong, the detachable mechanism, in the unit I toured, is completely driven by the haul rope. The haul rope goes over a pair of pulleys on each side, and it is these pulleys that drive the entire mechanism in the upper unit. (Imagining the lower wheel house is the same, adding a motor to the main bull wheel). I can see if there was no power whatsoever up in the upper wheel house, the chairs will still detach and reattach, etc... They need power for all the safety monitors and what have you, communications, etc....

Now about the power. 800 HP. I don't know how to convert that to KWH. Residential power is around 15 Cents per KWH, supply and distribution, give or take, not sure about commercial or industrial. (Anyone know?) Can you help me out with this?

That makes sense, I have never seen anything but typical 120V and low voltage comm wire going to the terminal without the motor.

It's a little over 4000 kWh for a 7 hour day under continuous use. $417 assuming 10 centers per kWh, then add your peak demand charge if their utility does that added to their distribution charges. It's likely quite a bit higher.

 

[IceEidolon]

Among ops staff at the mtn I work for, we say it's $70/hr for our high speed lifts.

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[Jully]

Among ops staff at the mtn I work for, we say it's $70/hr for our high speed lifts.

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That is crazy. Compared to a fixed grip lift, what is the difference? I'm not sure of the HP of fixed grip lifts, though I do know that it varies from lift to lift.

 

[IceEidolon]

Newpylong said $417, for the same timeframe $70/h is $490. That seems like a good ballpark estimate to me. Fixed grip lifts are, based on ResortBoneyard specs, in the 100-600 hp range (a 500' rise triple has a 200 HP motor).

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[Glenn]

It's always interesting to hear the stories from the folks who work on the mountain. Fascinating stuff.

 

[Jully]

I just talked to one of the head guys at the River this morning, inquiring about a few things. They were doing non destructive testing on the lift grips. Anyways, he said lifts are not the biggest power users, snowmaking is. Lifts eat up 5-7% of the resort power, about $2500 to 3000 per month. He said that once the lifts are moving, they are very efficient. I was astounded at that low number. Sunday River is second only to BIW in Maine for power consumption. Apparently they work a deal with CMP for sheer volume, and also agree to shed power usage on high electrical demand days when CMP needs that. (Read that turning off snowmaking).

Now I'm looking at what I was told for electrical usage number at the River, which is basically about $100 per day for all the lifts, verses $70 per hour. Despite asking again and receiving the same answer, I'm not so sure I trust the number given to me.

Makes a lot of sense that snowmaking would use much much more power. I'm surprised at the $100 per day number too given the previous discussion about the HP required. I find it extremely hard to believe that $100 a day covers 8+ hours of lifts starting and stopping and running. The lifts include 5 detachables, including many old ones that I'd have to guess are less efficient, and then a bevy of long fixed grip lifts. The White Heat Quad is like 450 HP itself.

Maybe I'm missing something or not understanding efficiency. Or maybe SR has an incredible deal with CMP.

 

[machski]

Makes a lot of sense that snowmaking would use much much more power. I'm surprised at the $100 per day number too given the previous discussion about the HP required. I find it extremely hard to believe that $100 a day covers 8+ hours of lifts starting and stopping and running. The lifts include 5 detachables, including many old ones that I'd have to guess are less efficient, and then a bevy of long fixed grip lifts. The White Heat Quad is like 450 HP itself.

Maybe I'm missing something or not understanding efficiency. Or maybe SR has an incredible deal with CMP.

I doubt once the lift is running at desired speed it uses anything near it's full HP. The HP rating is probably only used to start the lift and accelerate it to operating speed and then like a car, goes back to a much reduced power to maintain the speed.

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[benski]

I guess $70 an hour includes employees. Opening a ski area I guess is pretty cheep.

 

[mister moose]

Power consumed is about number of butts in the seats per hour and the vertical rise. Plus some frictional losses. Very little to do with fixed grip vs detach.

 

[IceEidolon]

That's assuming you don't have to start or stop the lift, which (especially for lifts that serve beginner terrain) is not the case. High speed lifts have a few hundred extra FPS to add to the haul rope. Not to mention accelerating a couple hundred pounds of skier and chair every six seconds during normal operation.

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[benski]

That's assuming you don't have to start or stop the lift, which (especially for lifts that serve beginner terrain) is not the case. High speed lifts have a few hundred extra FPS to add to the haul rope. Not to mention accelerating a couple hundred pounds of skier and chair every six seconds during normal operation.

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a normal detach still has constant momentum, since for every time a chair slows down another accelerates so I guess the two chairs balance out leaving the motor with just the skier to accelerate.