Public Policy Solves Only of 1/2 Our Transportation Problems, the Rest Is up to Hyperloops
Hyperloops have the potential to eliminate traffic, transit air pollution and our dangerous car obsession
Transportation sucks. Especially in North America, it sucks really bad.
Urban areas are stuffed with CO2 air pollution, and sidewalks are too squished or non-existent in some areas. While every few months the Ontario government needs to re-widen the highways when there is no more room for re-widening, and the constant traffic makes a 1-hour bus ride into 2.5. Most of us spend most of our days in traffic, with an average of 140–200 hours of idle time in 2022 in Canada (this was a low due to COVID!).
$165 billion is lost in productivity and wasted fuel annually from traffic
In North America, the problems with transportation aren’t only about pollution and traffic, it’s also about our poor views and cultures toward transportation.
- Cars are a sign of luxury, the nicer and more cars you have signal to others you are better off
- Public transportation is often not clean and always comes second to cars on the road
- Streets are designed with cars’ preferences in mind not for those who bus, walk or bike.
What if instead, we had a train that could carry hundreds of people over hour-long distances in only a few minutes by running at the speed of sound, 760 mph? Not only that but this super-speed train would be incredibly quiet, drive smoothly, and wouldn’t produce greenhouse gases.
That’s a hyperloop.
Even crazier, is that a version of the hyperloop was first proposed over 200 years ago in 1870, then more formally by rocket pioneer Robert H. Goddard in 1904, and later by vactrain advocate Robert M. Salter who wrote “The Very High Speed Transit System” in the early 1970s.
The rest of the 20th century saw a rise in hyperloop-like-tech from scientists and science fiction writers like Robert Heinlein (yes another Robert) who wrote about “vacutubes” in 1956, and in the early 1990s MIT researchers designed a 45-minute vacuum tube train from New York to Boston!
A few more years and ideas later, Elon Musk released the famous Hyperloop Alpha white paper.
Hyperloops solve major transit problems including air pollution, and traffic cutting your travel time significantly. On a hyperloop, a 5-hour trip (1 hour and 15 minutes non-stop flight) from Toronto to Montreal, Canada, would take only 39 minutes!
It is everything the everyday 9–5 working person, swamped high school student, etc. could want to get around, except of course until it isn’t.
Those problematic transportation views stated before are not going to magically disappear. No matter what amazing-sounding and futuristic mode of transportation is proposed, it will never fully succeed until these problems are also solved.
Linear Induction Motors (LIMs) hold hyperloops back
There are lots of limitations (especially safety ones) preventing hyperloop implementation. There are so many catastrophic ways you could die by getting into a hyperloop like a giant tube collapsing on you spewing thousands of tons of pressure, or a bridge collapsing.
One of the biggest limitations of hyperloops is trying to propel the hyperloop pods forward in tubes without any air. This would take huge amounts of energy and delivering it to parts that need massive energy is another issue in itself. Another is machinery vibrations which can rattle bolts lose or create microfractures leading to catastrophic tube failures. Not to mention, trying to maintain a near-vacuum tube (tube with no air) and control its thermal expansion in the summer as it runs over thousands of kilometres while supporting several pods would be a sci-fi miracle.
The biggest limiting factor is the hyperloop motor. The thing that is supposed to make it move!
LIMs allow hyperloops to travel at the speed of sound
A LIM, linear induction motor’s job is to move things in a linear motion.
LIM is made of 3 main components
- Stator (primary component)
- Coils
- Rotor (secondary component, or reaction plate)
Stator
LIMs have a sandwich-like shape, the pieces of bread are the outer pieces of metal called the stator and the rotor. The top piece of “bread” is called the stator, or the primary part and this piece of metal is attached to the underside of the hyperloop pod. An electrical current is introduced into the primary part and travels to the coils.
Coils
The primary part has copper coils attached to the bottom. Coils are made by winding around a copper wire, and an electrical current that comes from the primary part travels around the coils, but this gets fairly hot. So, coils are painted with epoxy to reduce mechanical vibrations, overheating and ensure temperature stability around the coils as current passes through them. All these things make sure that the LIMs can deliver more consistent and efficient performance for a longer time.
Rotor
The rotor is the bottom bread of the “sandwich,” is the bottom piece of metal that lies between the track rails. It’s also called the secondary part or the reaction plate since this is where the magic happens. The secondary part is made of a conducting aluminum or copper plate and usually has a steel backing which makes the LIM way more powerful.
Magnetic fields propel the pod forward
An electric current is introduced from top to bottom, so from the primary part (stator) and into the secondary part (rotor) on the bottom. In the primary part, as current is introduced, magnetic fields form and travel all along the primary part which is called magnetic flux (when magnetic fields pass through a specific area). When magnetic flux forms, eddy currents are induced in the secondary part (this is why induction is in the linear induction motor name). Eddy currents are when a current is induced in a conductor and moves in circular motions, basically like those circular currents that form in a flowing river, except here it is an electric current.
When the magnetic flux in the primary part and the induced currents in the secondary interact with each other, they produce a linear force, capable of pushing things in a linear motion.
LIMs aren’t new
LIMs aren’t new. They are over a century old and are still used in several everyday technologies including conveyor belts, sliding doors, and roller coasters.
LIMs are really good for any heavy-duty application, anything that is high speed, for long lengths, with lots of weight. So, LIMs are a great choice for high-speed transit like high-speed rails, launching spacecrafts into space, propelling electric vehicles (EVs) on highways like with the Speedway Transport System, and of course hyperloops.
Linear induction motors can go really fast for a really long time.
LIMs are ideal for applications that carry lots of weight and need to go fast for long periods of time because they have such a high linear force. In rotational motors, the linear force is called torque which is the rotational force of a rotating motor, and the higher the torque in a rotational motor the more efficient and faster the motor can spin.
This is the same concept with linear force, linear induction motors have some of the highest linear force compared to other types of linear motors. This allows them to travel over long distances while maintaining a high speed.
LIMs are confusing, inefficient, and expensive
LIMs are one of the biggest things preventing the technological acceleration of hyperloops, and the three main reasons for this are:
- LIMs have complex control systems
- Poor efficiency
- These along with other minute annoyances make LIMs super expensive
Overall LIMs are the best for any heavy-duty application, anything involving high speed, long performance time and lots of weight, but the three above factors significantly limit LIMs usage.
Complex control systems need more maintenance and longer construction periods
LIMs are confusing pieces of technology, they require advanced control systems to accommodate the changes in speed, temperature, and rail configurations (for the LIM it would be similar to train tracks for a train.)
Control systems need to be extremely precise, especially for hyperloops. For hyperloops, the goal is to travel super fast, 760 mph, and when operating at these super high speeds slight jolts that would be fine for small cars result in big discomfort and safety concerns in hyperloop pods plus eat away at energy really fast.
To overcome these challenges on top of unknowns that may happen during operation like unexpected weights or unexpected bumps, LIM control systems need to have high tracking performance and be good at not getting damaged by shaking or vibrations (also called high dynamic stiffness).
Poor energy efficiency is a pain that gets worse over time
LIMs are less efficient than other linear motors, meaning that they lose more energy during operation compared to other motors. All motors generally lose some energy, but the more energy a motor loses the less efficient it is. This energy is usually converted to heat, which serves no purpose to LIMs so that energy is wasted as it could have been used to make the LIM go faster.
One thing that makes LIMs less efficient is having a large air gap, so having a larger space between the primary (stator) and secondary parts (rotor) in other words the hyperloop pod and the track. When the space is bigger, magnetic fields need to travel farther which gives more opportunity for some energy to be lost along the way.
A less energy efficient motor will need more power to combat poor efficiency.
Less efficient motors lose more energy as heat, so the systems get warmer and may overheat. To combat this, we need to create cooling systems.
Cooling systems require even more energy to function. Cooling down the hot motors by circulating cold air/water ironically also generates lots of heat since you now have more moving parts. The cooling systems also increase the motor’s weight which means the motor needs to work harder, to account for more weight. This creates a vicious cycle of lower efficiency.
High costs are highly subjective to operation and construction issues and successes
Linear induction motors are already expensive due to the complex control systems and all the components added to increase energy efficiency. LIMs are also physically bulky and heavy, making them expensive to produce and hard to implement into the infrastructure for the application they are used for.
The big upside for LIMs is that they don’t use precious metals like rare earth elements (REEs) which are super expensive and are used in motors with permanent magnets.
Going forward rethinking technical issues should be the priority
To minimize LIM cost these technical challenges are the biggest priority for improvement. Once these challenges of complex guidance systems, energy efficiency, and physical structure have solutions that make them easier to handle, the cost problem will follow and lower.
Solutions that involve making small adjustments like adding more cooling components to an already hot, inefficient motor are not going to lower the cost enough to build a hyperloop. Instead, we need to rethink how these components work in a LIM and what we could do to speed up system response times or maintenance work. Rather than adding solutions that only slightly alleviate the superficial result and not the problem itself.
Linear induction motor control or guidance systems could be significantly levelled up if they can be more easily interpreted by maintenance workers, have more seamless interactions between feedback systems/sensors by using more sensitive materials (like materials with higher conductivity), or get a machine to calibrate sensors in real-time as new data from other feedback sensors comes in.
Linear induction motor energy efficiency could be super-upgraded if the air gap is more precisely controlled, machines control energy data from real-time magnetic fields, turn wasted heat (which is inevitable) into energy using materials like automotive thermoelectric generators (ATGs) for LIMs or use more efficient batteries overall.
My Hypothesis:
Smarter and More Energy Conscious LIMs Is the 1st Step to Hyperloops
Over the next few months, I’m going to do just that! Rethinking how we design linear motors to make them the most efficient they can be so you can get around faster and pollute the environment less.
Later on, I’ll build a few LIMs based on these new designs and aim to test them out with some of those LIM applications from above: conveyor belts, sliding doors, and roller coasters.
Hey! I’m Julia, thanks so much for reading my article, if you enjoyed it add a clap and follow on Medium for more on green energy and transportation.
Right now, I’m curious about exploring energy & transportation solutions, synthetic biology, and nanotech’s role in it all. For more from me, you can connect with me on LinkedIn and subscribe to my monthly newsletter!
