EE: Have a look at the Force Engineering website at http://www.force.co.uk and at the Power Superconductor Applications website at http://www.powersuper.com . Both sites have photos of LIMs under construction. Force built the original LIMs for Premier Rides; PASC built the replacements used on the Paramount Flight of Fear rides.
--Dave Althoff, Jr.
I don't know if its a "steeper" thing, but more of a "more efficent way of slowing the train" thing. I just think the brakes on KK are more powerful.
Ride Man's description of the LIM's is quite accurate. They are covered with a plastic type material though, not metal.
In the Pointbuzz photo though, it shows 2 LIM and a set of magnetic brakes. All the LIM's do is repel (thrust) the vehicle forward and do not assist in the braking at all. The magnets slow the train. The magnets are retracked upward during launch and reset back down during braking (you can hear them going either up or down)
The 2 sets of fins in the tops of the cars are for the most part the same material and are used in the repel mode during launch and in the brake mode during slow down. Again, the magnetic field is so strong between the 2 magnets it is unbeleivable and the fins cannot penetrate this very easily, thus reducing speed quickly.
The best way to think of a LIM is like magnetic braking. The difference is that the magnets are moving. There are a couple complictations that require electrical engineering to deal with so I will omit them
Whats going on is that the magnetic field interacts of the stators with the plate. It produces an eddy current in the plate. Normally there would not be any force in the desired direction but then the next field starts to increase. This causes an eddy current to form by the right hand rule with conventional current flow. With the direction of the current and the magnetic field, they produce a force in the direction that the motors magnetic field is "moving." If you want to think of it like streamer lights, it's very close to that. The exception is that there is a negative portion in the motors, but the current and magnetic field are in the opposite direction therefore the force is in the same direction as before. Because when there is no relitive motion between the moving field and the train there is no force, the train will lag behind the field a little bit. About 5-10% lag at full load is normal.
Synchronous motors (LSM are the linear counterpart) work simular. The big difference is that it uses magnets instead of reaction plates. There is already a magnetic field so inducing one isn't needed. The magnets follow the moving field created by the stators just fine. Actually they follow them at their exact speed up to full load then they slip off. Ok, to be technical, the magnet will fall behind a bit during acceleration and move forward during deceleration, but it should stay in a certain range unless the motor is overloaded. They are a little bit harder to use with a launch because when they slip, you "lose" the magnets and they can't catch up unlike a LIM. That was the problem that Superman the escape had when they couldn't get it to launch at first.
You guys may have seen these already, but I found some pics of Kingda Ka's hydrolic room. The review of how the ride works is over-simplified a bit. The guy says that KK uses magnets to slow the "catch car". Is that true? I thought it just slowed down on it's own after the train disengaged.
http://themeparks.about.com/od/photoandvideogallery/ss/KingdaHydraulic.htm
As for the brakes working better at a steeper angle, here's a tidbit I read somewhere... If its wrong, let me know.
I read that magnetic brakes create more stopping power the faster the vehicle is traveling through them. That is, it's a direct (maybe exponential) proportion between initial speed and stopping power; as one increases the other increases.
I also read that a magnetic braking system will never STOP a train. It will continue to slow it down more and more, but in theory would never stop.
Again, I dunno how true these are, and if anyone has some insight I'd love to hear it.
ROUNDABOUND.
Shane, braking force generated by magnetic brakes is proportional to speed, so yes, they can never completely stop the train. In fact, if you ever look at a train that has been stopped after a roll back, you can sometimes see it moving back very slightly when the brakes are up. Intamin gets around this on the brake run by using the drive wheels to position and hold the train once the magnets have slowed it down.
zskoz3, I'm pretty sure that the catch car is slowed using magnetic brakes. If you look at the launch track, you can see a third set of small fins in the middle of the track near the end of the run, and there is also one near the beginning and you can see the catch car slow as it goes over them if you ride front seat.
*** Edited 4/8/2006 8:38:43 PM UTC by Coasterfan***
-Paul
Yes, the catchcar is stopped by a separate set of brake fins. You can hear the catchcar going into them when the train reaches the end of the launch.
In fact, here's some cool pics of what an Intamin launch run looks like.
These are of Stealth at Thorpe Park(aka-Kingda Ka Jr.:)).
End of launch run and cable
Look down the launch run
beginning of launch run and catchcar Look a little more closely at the catchcar and you can actually see the fins are up inside of them.
*** Edited 4/8/2006 10:05:00 PM UTC by TTD 120mph***
-Adam G- The OG Dragster nut
If you look really really closely in this picture, you can see the brake fins on that same ride:
http://www.themeparkreview.com/miniuk2006/thorpe58.jpg
This one might be a little bit hard to see:
http://www.themeparkreview.com/miniuk2006/thorpe62.jpg
Their power plant, while less powerful, has better pictures. BUT! an even better video.
http://www.themeparkreview.com/videos/stealth.zip
You can find all of the pictures here:
I dont know if this was said..
http://www.sixflags.com/video/shared/greatadventure/kingda-ka_300.mov
In that movie, they show the Kingda Ka's launching system, which is almost identical to TTD
It's different in some small way....I cant remember how though. But yeah, it's pretty much the same as Dragster.
-Adam G- The OG Dragster nut
KK's system is more spread out. This helps the hydraulic to run more smoothly. I'm sure ForgottenEE knows more on this.
-Craig-
2008:Magnum XL-200 | Top Thrill Dragster
2007:Corkscrew | Magnum XL-200 | Maverick
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