40 replies to this topic

[mcjones55]

The pneumatic tube idea is in fact really old, the original new york subway was a pneumatic tube design. I think lifts have come a long way. for a brutally archaic rope and pulley system have a look at the san francisco cable car. They replace the haul ropes every 90 to 200 days of operation!!

[Matt]

In higher power (>10000HP) applications it's common to match the motor speed directly to the load speed through increased motor poles and/or lower frequency AC.

You could eliminate the gearbox and drive shafting by mounting the rotor poles of a synchronous motor directly to the bull wheel.

It would be cool to see this technique trickle down to lower power applications. There would be no motor or gearbox noise except for cooling fans. You would still have brushes to get power to the rotor, but because the current is much lower (just excitation), and there's no commutation (just slip rings instead of commutator), brush maintenance would be far lower.

The downside is the motor itself would be expensive. With electric motors it's the torque you pay for more than anything.

It's not really a new idea, it's just a new application for an existing technology.

[zbd2da]

it's still a gas fired engine but at least it's a step in a new derrection www.angellabsllc.com watch the animated video.

as for our traditional lifts they do the job very well with a very small foot print. aireal trams are being researched for use in large cities because of this tiny foot print and the limited space available.

electro magnets could be used to pull cars/cabins up hill. but they are very limited because you have to allow for return time and can only have one car on the track. i would think that the bank tube idea would have the same issue.

derect drive electric motors are already being used on several scoters and motorcycles www.electricmoto.com and http://www.gizmag.co.uk/go/4083/1/. with very strong torque figures.

the beem me up Scotty thing might be the coolest idea if it wher anywher near possible. but ski areas can't pay mechanics enought to survive as it is just imagine if they had to pay poeple with phds in partical restructure and de atomasation

This post has been edited by zbd2da: 09 June 2006 - 01:56 PM

[Jonni]

I still think that rather than trying to invent a new way to get people up the hill, it's better to improve upon what we already have to get them up there. High-Speed lifts for example was a great step in improving on our current uphill transportation. If we could improve upon that even more, then antiquated (spelling?) ideas like the good ol' chairlift won't seem that antique.

[Peter]

Jonni, I think your last post is this forums 40,000th post. Crazy!

This post has been edited by Skier: 09 June 2006 - 05:50 PM

[Jonni]

Sweet! I'm glad that I could be of assistance in that regard.

[Matt]

zbd2da, on Jun 9 2006, 02:55 PM, said:

derect drive electric motors are already being used on several scoters and motorcycles www.electricmoto.com and http://www.gizmag.co.uk/go/4083/1/. with very strong torque figures.

Yes this is fairly old technology in the cement and mining industries. They have standard 25Hz, 16.6666Hz and even a lowly 5.5Hz power for driving the biggest of these high torque (somewhere around 3 million ft-lb) monsters.

Emax, on Jun 10 2006, 08:36 AM, said:

This is interesting - but it's a nearly exact duplicate of the Vermel engine featured in an early sixties issue of Popular Science magazine. Still it's satisfying to see someone pick up on the idea.

I was going to say I remember seeing something very similar in a sixties era mechanical engineering textbook. The whole cylinder block rotated if I'm not mistaken.

[Bill]

If we are talking bad, like wood fired, how about coal? Imagine the soot from that on your precious white gold. (If we dirtied the snow, we had to clean it up, but shovelling fresh white stuff over the mess).

[Lift Dinosaur]

You could eliminate the gearbox and drive shafting by mounting the rotor poles of a synchronous motor directly to the bull wheel.

It would be cool to see this technique trickle down to lower power applications. There would be no motor or gearbox noise except for cooling fans. You would still have brushes to get power to the rotor, but because the current is much lower (just excitation), and there's no commutation (just slip rings instead of commutator), brush maintenance would be far lower.

The downside is the motor itself would be expensive. With electric motors it's the torque you pay for more than anything.

It's not really a new idea, it's just a new application for an existing technology.
[/quote]

An example from LEITNER
 LEITNER_Direct_Drive.jpg (48.08K)
Number of downloads: 64  LEITNER_Direct_Drive_OH_View.jpg (27.67K)
Number of downloads: 63

[Lift Dinosaur]

Emax, on Nov 2 2006, 10:17 AM, said:

Dino - didn't you post this once before? Please explain the fotos phurther.

Don't remember - I'm a dinosaur!

What you see is Leitner's Direct Drive system.
"The system simply comprises a slow running electric motor with permanent power take-off at the bullwheel without the use of a gearbox.Advantagesin terms of the quality of the ride derive from the low levels of viabration and noise emissons as well as fast line speeds and high transport capacities. The economic advantages are also exciting: minumum maintenance (on oil change), meaningful energy savings (negligible frictional losses and up to 15% savings in energy consumption thanks to direct transmission of power from the electric motor to the bullwheel), greatly reduced mechanical wear for longer service life (with the rotor and the 2 bearings as the only moving parts)."
The first installation was in Ladurns, Italy in 1999. Detachable quad 1688m long, 575m vertical, 525KW, 1665pph. They have since done 4 or 5 more.
They also use this technology in their LEITWIND wind generators.

[Matt]

Lift Dinosaur, on Nov 2 2006, 11:33 AM, said:

Don't remember - I'm a dinosaur!

What you see is Leitner's Direct Drive system.
"The system simply comprises a slow running electric motor with permanent power take-off at the bullwheel without the use of a gearbox.Advantagesin terms of the quality of the ride derive from the low levels of viabration and noise emissons as well as fast line speeds and high transport capacities. The economic advantages are also exciting: minumum maintenance (on oil change), meaningful energy savings (negligible frictional losses and up to 15% savings in energy consumption thanks to direct transmission of power from the electric motor to the bullwheel), greatly reduced mechanical wear for longer service life (with the rotor and the 2 bearings as the only moving parts)."
The first installation was in Ladurns, Italy in 1999. Detachable quad 1688m long, 575m vertical, 525KW, 1665pph. They have since done 4 or 5 more.
They also use this technology in their LEITWIND wind generators.

That's pretty cool that they've already done it. They use a permanent magnet synchronous motor according to the website. All the synchronous motors I've seen have been DC excited, but I've read about PMSM's (Permanent Magnet Synchronous Motor) used in cruise ship azipod propulsion.

What's a typical bullwheel RPM? I want to calculate torque on that.

[mikest2]

Matt, on Feb 24 2007, 07:48 PM, said:

That's pretty cool that they've already done it. They use a permanent magnet synchronous motor according to the website. All the synchronous motors I've seen have been DC excited, but I've read about PMSM's (Permanent Magnet Synchronous Motor) used in cruise ship azipod propulsion.

What's a typical bullwheel RPM? I want to calculate torque on that.

5 m/s, 4m diameter bullwheel

[Matt]

mikest2, on Feb 24 2007, 08:56 PM, said:

5 m/s, 4m diameter bullwheel

I get around 155,000 ft*lb, pretty big machine. (Assuming that 525kW correlates to a service speed of 5 m/s).

[Lelec]

Matt, on Jun 1 2006, 10:39 PM, said:

In higher power (>10000HP) applications it's common to match the motor speed directly to the load speed through increased motor poles and/or lower frequency AC.

You could eliminate the gearbox and drive shafting by mounting the rotor poles of a synchronous motor directly to the bull wheel.

It would be cool to see this technique trickle down to lower power applications. There would be no motor or gearbox noise except for cooling fans. You would still have brushes to get power to the rotor, but because the current is much lower (just excitation), and there's no commutation (just slip rings instead of commutator), brush maintenance would be far lower.

The downside is the motor itself would be expensive. With electric motors it's the torque you pay for more than anything.

It's not really a new idea, it's just a new application for an existing technology.

I have toured these systems in Europe and they work fairly well with several caveats. The main goal was the elimination of the gearbox and this has been accomplished (albeit with motors the size of Cleveland - to my knowledge only the last system built incorporated the motor on the bullwheel, the others had large below ground motor rooms and drive shafts). There are, however, problems with the application of this technology to ski lifts and aerial tramways.

The first problem (at least in North America) is this: how do you supply a customer with a full speed auxiliary system? Such systems are in high demand in our market due to power fluctuations, outages etc. In Europe they generally use an electric drive/motor as the primary with a diesel driving a small hydrostatic system (ring gear coupling to the bullwheel) for evacuation, don't use full speed auxiliary systems and therefore don't have this problem. The hydrostatic setup could be beefed up and converted to a full speed system and be viable but the expense is huge.

The second problem that I see with such systems is the change in rotational inertia of the system. A standard electric motor rotating at 1300 to 1750 RPM generates much more rotational inertia than the motors you describe, which operate at very low RPM (using a 4 meter or approximately 13 foot diameter bullwheel at 1000 fpm = > (1000 ft/min)/(13*pi ft/rev) = 24.49 rpm (!!!)) Low values in this area make brake system setups very difficult or impossible, even with the large (massive) motors making some of it up. I am sure that there are many lift mechanics out there that will attest to the problems involved in setting up brakes for low inertia systems. One of the systems I saw had to have MASSIVE flywheels added to it because a fully loaded uphill E-Stop basically caused the lift to stop on a dime with no brake applied.

Finally, you mention expensive motors but there is also a high dollar value associated with the drive system for such a motor. While there are large cost advantages (obviously) to not having a huge gearbox, these are generally offset and even exceeded by the added cost of the drive/motor system.

Some of the advantages you list, such as no brushes and commutator can be realized with standard AC motors and next generation IGBT based drives and low current systems can be actualized by going to medium voltage systems. While there are additional advantages (faulty poles can changed out in a modular sense and even ignored with a small loss in torque) they do not make up for the costs and associated disadvantages. The truth is this technology was developed for the Leitwind project, where it is much more suited for use, and the application to ski lifts is an offshoot which, in my opinion, won't take root in North America. By the way, if you are an engineer (or soon to be) and are looking to enter the lift industry then email me, I may be able to help.

[Emax]

Here's an interesting idea for a lift that doesn't use a rope. Each chair is self-powered via linear induction: permanent magnets on the chair, actuated magnets on the rail.

[Jonni]

Looks like an interesting invention, though kinda of unconventional for some applications. A design like this would appear to be only viable for lower to the ground installations that don't have long spans between towers. The upside would be there there really wouldn't be that many moving parts, and the lift would be exceptionally quiet. Interesting find though!

[ski89]

Seems like an advantage to have the variable speeds in order to maximize pph but wouldn't you be wasting energy by not connecting the uphill chair to the downhill chair or could the returning chairs generate power on the return trip.

[Emax]

Well - permanent magnets on the chair would guarantee the possibility of power generation on the down-hill run - but it would be hard to convert it to a form compatible with the power grid (thus helping the uphill carriers up the hill). Maybe it could be used as DC to heat places that needed it - either that or run the marketing dept. computers and vibrators.

[defence2]

Emax, on Apr 17 2007, 05:12 PM, said:

Here's an interesting idea for a lift that doesn't use a rope. Each chair is self-powered via linear induction: permanent magnets on the chair, actuated magnets on the rail.

5158021.pdf

I'd agree that having to connect all the lift towers by an I-beam as shown in the drawings seems impractical, but couldn't this be adapted for loading and unloading stations on detachable quads. Seems that this would simplify the stations.

[mikest2]

Emax, on Apr 20 2007, 12:22 PM, said:

Well - permanent magnets on the chair would guarantee the possibility of power generation on the down-hill run - but it would be hard to convert it to a form compatible with the power grid (thus helping the uphill carriers up the hill). Maybe it could be used as DC to heat places that needed it - either that or run the marketing dept. computers and vibrators.

I think marketing already generates enough hot air to power the lift. How would one control the deceleration curve in a power outage situation ?