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California Screamin' - LIM or LSM?


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Alright, so I was looking at some pictures of CA Screamin's launch run, and while RCDB lists the ride as LSM launch, the assemblies on the launch run are basically the same as the LIM motors on Impulse coasters.

 

I did some research, and found that certain sites list the ride as LSM, some as LIM, some as LIM/LSM, and some refuse to say anything but "launched coaster". So which is it?

 

I'm almost inclined to say LIM here, and blame the mistake on the fact that Disney usually never release much information as to how their rides work.

 

Anyone have more information?

 

Pictures for comparison:

 

Wicked Twister (LIM): http://www.rcdb.com/ig1571.htm?picture=10

 

CA Screamin': http://lostworld.pair.com/disneyland/california_adventure/paradise_pier/images/71_screamin_launch.jpg

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It's LSM.

 

LIM's are what rides like Italian Job use. You can see the difference in the setup:

 

http://rcdb.com/ig2861.htm?picture=18

 

With an LSM system, the train has copper fins that go very close to the magnets. The LSM's also switch from AC to DC as the train passes.

 

A LIM system.....well here is a very detailed explanation:

 

http://capital2.capital.edu/admin-staff/dalthoff/lim.html

 

So judging by the way it looks....I'd say it's LSM.

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It's LSM.

 

LIM's are what rides like Italian Job use. You can see the difference in the setup:

 

http://rcdb.com/ig2861.htm?picture=18

 

With an LSM system, the train has copper fins that go very close to the magnets. The LSM's also switch from AC to DC as the train passes.

 

A LIM system.....well here is a very detailed explanation:

 

http://capital2.capital.edu/admin-staff/dalthoff/lim.html

 

So judging by the way it looks....I'd say it's LSM.

 

In that case, would Wicked Twister be LSM as well? It's basically the same assembly, just mounted upside down...

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The difference between a LIM (Linear Induction Motor) and an LSM (Linear Synchronous Motor) is pretty simple, but the same basic concept. LIMs use a non-ferous (non-magnetic, usually either aluminum or copper) "fin" that runs through the fixed portion of the motor. LSMs use rare earth magnets with very high magnetic flux that run through the fixed portion of the motor.

 

Superman at Six Flags Magic Mountain is the only launched coaster that I know of that uses LSMs (though I'm sure there's another version of this same launch technology somewhere)

 

Pretty much every other launched coaster you can think of is a LIM... California Screamin', Revenge of the Mummy, and yes even Big Thunder Mountain (though it's not a launched coaster, it still uses LIMs in the station and storage.

 

A little more information about Synchronous Motors and Induction Motors...

 

Induction motors do just as their name implies, the INDUCE a magnetic field into a non-ferous core, which then reacts to create mechanical motion. There is always a "slip" speed associated with an Induction motor that will vary with the load applied. In general Induction motors are MUCH cheaper, but require some rather complex electronics to control.

 

Synchronous motors do not have to induce a magnetic field into the core, the magnetic field is already present in the form of rare earth magnets. Consequently this results in a "dead-nuts" rotor or linear speed regardless of the load applied (up to the stall load).

 

In both types of linear versions of these motors timing is critical. The amount of power applied to these motors is intense, it's essentially a welder on steroids. As long as the core is present for all of that energy to produce motion, everything is good. But as we all know, roller coaster move and leave the stationary portion of the motor. If the required amout of power were applied to the motor with no core (no train) present, the sucker would melt so quickly you wouldn't believe it.

 

Anyway... That's enough electrical engineering for the day (which is generally not my forte)... back to mechanical

 

Summary:

The MAJORITY of launched coasters utilizing Linear Motor technology would be categorized as Linear Induction Motors (LIMs)

 

Hope all this made sense!!

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LSM are used on some Intamin coasters like the Aquatrax, the Half Pipe or the Ball Coaster.

 

But I have another question now for the electrical engineering specialist Can we use LSM as a launch system but as a braking system too, like a normal magnetic brake ? Because on the launch track of Atlantis Adventure, there are LSM bot no retractable anti rollback system like the brake fin on the Rocket Coasters.... Why ?

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I'm pretty sure that the Half Pipe are LSM launched. I visited Särkänniemi two years ago and I was able to see the backstage of Half Pipe and the frame of the train. There are no metal fin under it, its permanent magnets, so it can only be LSM. Plus the LIM on coasters alwys work with two motors, not one

 

Here are the LSM on Half Pipe and on the Ball Coaster. The same system will be also used on the new Cedar Point's coaster

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But I have another question now for the electrical engineering specialist Can we use LSM as a launch system but as a braking system too, like a normal magnetic brake ? Because on the launch track of Atlantis Adventure, there are LSM bot no retractable anti rollback system like the brake fin on the Rocket Coasters.... Why ?

 

Of course you can. Motors are able to be wired such that they induce or retard mechanical motion. All that is required is a resistive load back to dump that power somewhere.

 

Remember back to Physics, conservation of energy. Wired as a motor, you're converting potential energy (electricity) into kinetic energy (roller coaster motion). Now... just reverse it, you just have to have some place to dump all that power, generally, you end up converting that power to heat. In general, power companies frown on you trying to dump that back into the power grid because they don't make money on it

 

I've never been on Atlantis Adventure but it sounds like they may be using the LSMs in this fashion.

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From www.vekoma.com :

 

"Riders experience a launch from zero to 90 kilometers per hour in less than three seconds on our LSM (Linear Synchronic Motor) Launch Coasters."

 

Remember, websites are, in general, created by NON-technical people who often screw up the technical aspect. It's best to actually take a look at the system to determine the type, or speak with a technical representative.

 

As an engineer that uses COTS (Commercial Off-The-Shelf) parts on a fairly regular basis, I've been burned more than once with a product dimension or capacity mis-represented by a "pretty" website. Moral of the story: don't believe everything you read

 

This is NOT to imply that Vekoma doesn't use Linear Synchronous Motors, I just happen to question the validity in the English translation of "Synchronic".

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I'm pretty sure that the Half Pipe are LSM launched. I visited Särkänniemi two years ago and I was able to see the backstage of Half Pipe and the frame of the train. There are no metal fin under it, its permanent magnets, so it can only be LSM. Plus the LIM on coasters alwys work with two motors, not one

 

They can work either way, and the system can definately operate with one motor.

 

In other words, the motors could be on the trains and the fins on the track, or the motors on the track and the fins on the train. As long as the reaction between them exists.

 

Either assembly or the reaction plate can be the moving member of the motor. Typically the reaction plate becomes part of the customer load moving over stationary coil assemblies placed end-to-end for the travel distance.

 

By contrast, LSM coasters use much larger reactive magnets, not simple fins, to establish a connection and create linear force.

 

Therefore, Half-Pipe is definately LIM powered, it just isn't the more common way of doing it.

 

http://www.baldor.co.uk/products/linearproducts/lmac.asp

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California Screamin' definitely uses Intamin LIM technology. I believe Intamin abandoned LSMs after the Superman/Tower of Terror build.

 

Vekoma's is also a variant of the LSM technology that uses a sled with the magnet on it instead of magnets on the train cars.

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Having looked into this for years now, I think I can safely say that the only "theme park" based attractions that use Linear Synchronous Magnet technology today would be the Tower of Terror/Superman: The Escape.

 

To place things into an absolute and utter nuthsell, both designs of technologies are effective in their own applications, however while they essentially lie on the same principles, there's still some big factors that differentiate the two.

 

Let's first take a look at the TOT/STE LSM technology. Here we have incredibly fast accelerating technology that relies on "synchronising" singular sets of copper blocks to draw in the earth magnets attached to the pod. When the pod runs over the first set, an electrical flux is formed, and the pod is pushed onto the next set, whereby the next copper blocks draw in the pod, repeatting the process in a fashion that is "synchronised" to efficiently acheive faster speeds in a smaller incline setting.

 

Roller-coasters like California Screamin' use a slightly different approach. Instead we have a much less technologically advanced outlook on how the train launches. In short, rather than "synchronising" singular blocks in a simultaenous "push and pull" motion seen in LSM technologies, we have a "set" of electromagnets pushing in one linear motion (forward obviously) much like Maglev trains do, acheiving an ableit, more cost effective but more efficient approach to launching a coaster.

 

To back up this claim also, the Discovery Channel did an in-depth look at Superman: The Escape back in 2003 or so, and compared the technologies used (such as LSM and LIM) to air powered launches and hydraulic launches (back in a day where only Xcelerator was around.)

 

Hope this helps.

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...Kind of

 

Although the above explanation is correct in its description of operation there's one key thing that is missing.

 

LSMs in themepark attractions operate as separate entities, each motor catches and releases the ride vehicle

 

LIMs have much more interaction and the ride vehicle essentially "rides" and induced wave down the bank of motors.

 

Let's back up just a bit though. Synchronous and Induction motors have very similar construction and follow many of the same principles. However, the MAIN factor that differentiates the two in terms of performance is:

 

Synchronous motors have FLAT Torque vs. Speed Curves. This means that regardless of the speed, the motor is always capable of developing maximum torque (or force in a linear motor)

 

Induction motors have an associated startup torque, maximum torque and associated maximum speed torque (which is lower than starting torque)

 

I just want to clear up that the term "synchronous" is NOT supposed to be used to define the interaction between multiple synchronous machines as used in rides like Superman at SFMM. It's a term associated with the individual machine and refers to the rotor speed vs the rotating flux speed, which in a synchronous motor are identical (or SYNCHRONIZED )

 

Cool?

 

Enough dorky engineering junk!

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I dont know much about them, but I'd have to say that they are lsms, if rcdb says it, i'd guess it would be true. I think CA Screamin' and Wicked twister's look different.

 

I did notice, however, that CA screamin's lift looks like LIM's if I remember correctly from a POV I've seen.

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