# Linear Induction Motors

Tuesday, October 9, 2001 12:47 PM
Where can you buy LIMs ? How much do they cost ? and how much power is needed to run them ?
I read somthing a while back that every time Mr.Freeze is launched it uses 2,000,000 volts of Electricity, that is with 224 LIMs.
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Mr.Freeze Laps :30

*** This post was edited by TITAN_FAN_13 on 10/9/2001. ***

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Tuesday, October 9, 2001 12:57 PM
"but LIMs"? I think you mean "buy" and you can't buy them, so don't even try.
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I've got laser eyes, and I know what you're thinking. It comes to no surprise, the Christmas lights are blinking.
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Tuesday, October 9, 2001 1:00 PM
Well first of all

Voltage is not in terms of use it is just potential applied, The unit of a watt is used to describe the use of electricity. In your house it is in terms of Kilowatt Hours.

The amount of power needed would depend solely on the amount of work the LIM would have to do in this case of coasters it is relative to the amount of energy it takes to accelerate a coaster train to the desired speed. Wich is mostly related to the weight.

I doubt any lim uses a voltage potential of  2 Mega Volts.

I am not aware you can buy LIMS from anyone, But for the most part they are just electro magnets wich you can buy the material to make or buy them. The hard part if you are thinking of using LIMS would be Getting them to work correctly.

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Tuesday, October 9, 2001 1:05 PM
Volts are not a unit of electricity, watts are. I have no trouble believing 2 megawatts of power. If you are launching for five seconds per minute at two megawatts, and electricity is costing you five cents per kilowatt hour, the cost per launch is fourteen cents. The cost per hour is about nine dollars. Not a huge deal. The problem is that you need very high current for a short period of time, which necessitates very heavy wiring and very expensive drive electronics. The cost to operate is roughly in like with other coasters, which makes sense. It requires the same amount of energy to lift a twenty ton vehicle 200 feet whether you accelerate them then let momentum do its thing or lift them directly. It requires more power, but you pay for energy, not power. Linear motors themselves are not cheap, however.

About ten bucks an hour is a good back of the envelope estimate for power cost, unless you live in california, in which case power is slightly more expensive thanks to consumer-friendly deregulation efforts. (-;

Also as an FYI 2 megawatts is ~2700 horsepower, so you would get a net of maybe 2000 horse, which seems in line with the weights and accelerations needed.

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Tuesday, October 9, 2001 1:09 PM
WOW!!  for the first time I really understood all of that, That is cool how all Electricty and stuff like that works.
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Tuesday, October 9, 2001 1:17 PM
Glad to be of assistance. Realistically, though, if you have even a fraction of the money that you need for your venture already, you can just write to intamin and ask for a spec sheet, I know the place where I work is more than happy to jump through hoops to get information to potential customers. They'd probably give you a number in either joules or kilowatt/hours or kilowatts/launch. I'd be interested to see that number, if just to see how close my first order approximation was.

Coma

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Tuesday, October 9, 2001 1:24 PM
Baldor sells a line of linear induction motors, most designed to operate at 480 VAC so that they can be used with their vector drive motor controllers; see their product catalog at http://www.baldor.com/pdf/brochures/br1800/Section6.pdf . Be sure to look at the other sections as well. The fact that LIMs are in the Baldor catalog indicates that you can obtain them (probably by special order) from most any reputable industrial electrical supplier. Caution: Probably not cheap! :)

But there are smaller motors available with load capabilities of just a few pounds which would be suitable for use in demonstrations and the like.

--Dave Althoff, Jr.

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Tuesday, October 9, 2001 1:56 PM

Comatose said:
and electricity is costing you five cents per kilowatt hour

HAHAHA thats funny

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Tuesday, October 9, 2001 6:08 PM
Dave, just curious as to the manufacturer Intamin uses for LIM components.  I believe that Premier uses (or at least has used) Force Engineering stators.
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millforce
--who would love to see more LIM launched coasters, especially in Ohio!--
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Tuesday, October 9, 2001 6:15 PM
TITAN_FAN_13 -

You just can't go out buying linear induction motors. They (LIMs) cost a lot! Would you have that kind of money to buy them, and what would you do with them? Just look at them the whole time? So you got \$15+ million dollars in your pocket?

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"Duff Man Says... Ohhh Yeah!"
Current Favorite Coasters:
1)Raging Bull 2)Millennium Force 3)Medusa (SFMW) 4)Vertical Velocity (SFGAm) 5)Dueling Dragons (Ice)

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Tuesday, October 9, 2001 7:22 PM
millforce, the original LIMs on the Premier LIMCat coasters reportedly came from Force Engineering, but in an interesting conversation with Dr. Kunetsov at IAAPA last year, I learned that apparently Paramount swapped out the Force motors in favor of motors from PSM Maglev instead. I'm not sure whose motors Intamin is using.
The thing is, LIMs are not some exotic technology. They are a fairly mature and well-established technology, and they are really quite simple. Basically a LIM is little more than a multi-pole coil of wire. They are simpler than standard rotary induction motors because there are no bearings to deal with. Just like rotary motors they come in various shapes and sizes and load capacities.

--Dave Althoff, Jr.
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Tuesday, October 9, 2001 7:45 PM

StealthmF5m3, if you've followed the saga TITAN_FAN has ambitions of building an amusement park.  We've already covered the cost of B&M's, CCI woodies, and I believe Intamin coasters.  Many support him, some laugh at him.  I think he's just dreaming because I think he's a little kid.  I'll use the following quote to rest my case:

TITAN_FAN_13 said:
That is cool how all Electricty and stuff like that works.
I don't mean any harm and I'm not trying to stop anyone from having a good time.  I just don't believe that anything tangible will ever come from these discussions.

*** This post was edited by Incidentalist on 10/10/2001. ***

*** This post was edited by Incidentalist on 10/10/2001. ***

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Tuesday, October 9, 2001 9:11 PM

Wackokid said:

Comatose said:
and electricity is costing you five cents per kilowatt hour

HAHAHA thats funny

Actually it isn't particularly funny, at least not where I live. Residential customers are nine cents per kilowatt hour. Industrial costomers are significantly less.
You absolutely can buy LIMs off the shelf, and they do not necessarily cost "millions of dollars"

Nevermind, I neglected to check that you are, in fact, in california where the laws of supply and demand have nothing to do with what you're paying for power. Sorry.

*** This post was edited by Comatose on 10/10/2001. ***

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Tuesday, October 9, 2001 10:16 PM
its ok, i dont even know what any of that means anyway

howd you know i was in california? i didnt have it in my profile (until just now)...

*** This post was edited by Wackokid on 10/10/2001. ***

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Tuesday, October 9, 2001 11:10 PM

Wackokid said:
its ok, i dont even know what any of that means anyway
howd you know i was in california? i didnt have it in my profile (until just now)...
*** This post was edited by Wackokid on 10/10/2001. ***

I am super-smart...
Actually I looked at your coaster list and made an educated guess. Similarly you could conclude I live in Ohio if I took the time to make one, as the majority of my coasters would be in Ohio. Cept I'm actually in Pittsburgh right now, on account of school.

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Wednesday, October 10, 2001 6:04 AM
Comatose: \$0.09/kWh? My latest electric bill says I'm paying \$0.044/kWh for residential service. When I heard that California was getting a 50% increase..."an increase of about \$0.25/kWh" I realized how incredibly expensive power must be out there...! \$0.75/kWh!? Yikes!

--Dave Althoff, Jr.

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Wednesday, October 10, 2001 6:20 AM

Incidentalist said:

StealthmF5m3, if you've followed the sage TITAN_FAN has ambitions of building an amusement park.  We've already covered the cost of B&M's, CCI woodies, and I believe Intamin coasters.  Many support him, some laugh at him.  I think he's just dreaming because I think he's a little kid.  I'll use the following quote to rest my case:

TITAN_FAN_13 said:
That is cool how all Electricty and stuff like that works.

I don't mean any harm and I'm not trying to stop anyone from having a good time.  I just don't believe that anything tangible will ever come from these discussions.

This has nothing to do with my Project I have talked about before, this is on LIMs

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Wednesday, October 10, 2001 7:27 AM
Rideman:  You must be on top of a coal mine if you are getting residential electricity for \$.044/Kwh.  That's cheap even for industrial power in most areas.

General:  Industry and large commercial users such as amusement parks don't pay for electricity the same way that households do.  Power companies structure their rates fro industry to try to persuade you to make your usage fit their needs.  If you don't you pay more.

Rates frequently vary by time of day, and peak demand is also charged for.  In other words, if you use a lot of power for just 30 minutes per day you pay extra for that power since the electric company has to have transformers, wires, switchgear, etc. that can supply that peak and ther sits there underutilized the rest of the day.

LIM launches are a good example of this since they use a lot of power in short burts.  Actual power consumption during launch may be 4 to 6 megawatts for a few seconds, then no more power is used until the next launch.

The information that I've seen on LIMs gives them a pretty low efficiency.  Conventional rotating synchronous motors are about 85% efficient today.  An LIM is only about 50% efficient.  So, it takes electricity equivelent to 6000 horsepower to provide 3000 horsepower to launch a train.

Yes you can buy an LIM, but the type sued to launch a coaster is custom built with special controls and is very expensive.  The cataloged LIMs are usually little round things with a shaft that moves a few inches.  Kind of a stepper solenoid.

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Wednesday, October 10, 2001 7:58 AM
Actually, Jim, if you look at that Baldor Acrobat file, they have brushless flat linear motors, the stepper solenoids you mention, and the single-sided flat-plane LIMS that require a customer-supplied reaction fin and backing plate. The huge expense is actually not in the motor itself (it's just a coil of wire enclosed in epoxy) but in the thousands-of-dollars vector drive controller or the hundreds-of-dollars variable frequency drive.

And yes, the ones used for launching coasters (typically double-sided LIMs) are custom built with high-end controls.

Oh, and the \$0.044/kWh is the comparison price for my power here in Columbus, OH, and doesn't include the delivery charges and taxes...that's the 'fuel rate' that can vary with the electric supplier. Actual cost per kWh isn't a whole lot more than that.

--Dave Althoff, Jr.

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Wednesday, October 10, 2001 8:13 AM

Incidentalist said:
"StealthmF5m3, if you've followed the sage TITAN_FAN has ambitions of building an amusement park.  We've already covered the cost of B&M's, CCI woodies, and I believe Intamin coasters.  Many support him, some laugh at him.  I think he's just dreaming because I think he's a little kid.

Titan, if this is true, folloW your dream....and remember Antuan from Coasterbuzz when you establish that park ;)

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