When thoughts turn to the modernization and decarbonization of our transportation infrastructure, one imagines it to be dominated by exotic materials. EV motors and wind turbine generators need magnets made with rare earth metals (which turn out to be not all that rare), batteries for cars and grid storage need lithium and cobalt, and of course an abundance of extremely pure silicon is needed to provide the computational power that makes everything work. Throw in healthy pinches of graphene, carbon fiber composites and ceramics, and minerals like molybdenum, and the recipe starts looking pretty exotic.
As necessary as they are, all these exotic materials are worthless without a foundation of more familiar materials, ones that humans have been extracting and exploiting for eons. Mine all the neodymium you want, but without materials like copper for motor and generator windings, your EV is going nowhere and wind turbines are just big lawn ornaments. But just as important is iron, specifically as the alloy steel, which not only forms the structural elements of nearly everything mechanical but also appears in the stators and rotors of motors and generators, as well as the cores of the giant transformers that the electrical grid is built from.
Not just any steel will do for electrical use, though; special formulations, collectively known as electrical steel, are needed to build these electromagnetic devices. Electrical steel is simple in concept but complex in detail, and has become absolutely vital to the functioning of modern society. So it pays to take a look at what electrical steel is and how it works, and why we’re going nowhere without it.
About two decades ago there was a quiet revolution in electronics which went unnoticed by many, but which overturned a hundred years of accepted practice. You’d have noticed it if you had a mobile phone, the charger for your Nokia dumbphone around the year 2000 would have been a weighty device, while the one for your feature phone five years later would have been about the same size but relatively light as a feather. The electronics industry abandoned the mains transformer from their wall wart power supplies and other places in favour of the much lighter and efficient switch mode power supply. Small mains transformers which had been ubiquitous in electronics projects for many years, slowly followed suit.
Coils Of Wire, Doing Magic With Electrons
A transformer works through transferring alternating electrical current into magnetic flux by means of a coil of wire, and then converting the flux back to electric current in a second coil. The flux is channeled through a ferromagnetic transformer core made of iron in the case of a mains transformer, and the ratio of input voltage to output voltage is the same as the turns ratio between the two. They provide a safe isolation between their two sides, and in the case of a mains transformer they often have a voltage regulating function as their core material is selected to saturate should the input voltage become too high. The efficiency of a transformer depends on a range of factors including its core material and the frequency of operation, with transformer size decreasing with frequency as efficiency increases.
When energy efficiency rules were introduced over recent decades they would signal the demise of the mains transformer, as the greater efficiency of a switch-mode supply became the easiest way to achieve the energy savings. In a sense the mains transformer never went away, as it morphed into the small ferrite-cored part running at a higher frequency in the switch-mode circuitry, but it’s fair to say that the iron-cored transformers of old are now a rare sight. Does this matter? It’s time to unpack some of the issues surrounding a small power supply. Continue reading “Parts We Miss: The Mains Transformer”→
When we first developed telescopes, we started using them on the ground. Humanity was yet to master powered flight, you see, to say nothing of going beyond into space. As technology developed, we realized that putting a telescope up on a satellite might be useful, since it would get rid of all that horrible distortion from that pesky old atmosphere. We also developed radio telescopes, when we realized there were electromagnetic signals beyond visible light that were of great interest to us.
Now, NASA’s dreaming even bigger. What if it could build a big radio telescope up on the Moon?
Depending on the age of your car, it might contain a round 12 V power outlet in the dash, or possibly in the elbow compartment. And depending on your own age, you might know that as the cigarette lighter port. Whereas this thing used to have a single purpose — lighting cigars and cigarettes via hot coil — there are myriad uses today, from charging a phone to powering a dash camera to running one of those tire-inflating machines in a roadside emergency.
But how did it come to be a power source inside the vehicle? And how long will it stick around? With smoking on the decline for several decades, fewer and fewer people have the need for a cigarette lighter than do, say, a way to charge their phone. How long will the power source survive in this configuration?
Every time there’s a plane crash or other aviation safety incident, we often hear talk of the famous “black box”. Of course, anyone these days will tell you that they’re not black, but orange, for visibility’s sake. Plus, there’s often not one black box, but two! There’s a Flight Data Recorder (FDR), charged with recording aircraft telemetry, and a Cockpit Voice Recorder (CVR), designed to record what’s going on in the cabin.
It sounds straightforward enough, but the cockpit voice recorder has actually become the subject of some controversy in recent times. Let’s talk about the basics of these important safety devices, and why they’re the subject of some debate at the present time.
That’s because the team at Sierra was looking to find the ultimate bust pressure of their 8.2 meter (26.9 foot) diameter Large Integrated Flexible Environment (LIFE) module — a real-world demonstration of just how much air could be pumped into the expanding structure before it buckled. NASA recommended they shoot for just under 61 PSI, which would be four times the expected operational pressure for a crewed habitat module.
By the time the full-scale LIFE prototype ripped itself apart, it had an internal pressure of 77 PSI. The results so far seem extremely promising, but Sierra will need to repeat the test at least two more times to be sure their materials and construction techniques can withstand the rigors of spaceflight.
Sierra is a targeting no earlier than 2026 for an in-space test, but even if they nail the date (always a dubious prospect for cutting edge aerospace projects), they’ll still be about 20 years late to the party. Despite how futuristic the idea of inflatable space stations may seem, NASA first started experimenting with the concept of expandable habitat modules back in the 1990s, and there were practical examples being launched into orbit by the early 2000s.
It’s 2024. NASA’s Artemis program is in full swing, and we’re hoping to get back to the surface of the Moon real soon. Astronauts haven’t walked on the beloved sky rock since 1972! A human landing was scheduled for 2025, which has now been pushed back to 2026, and we’re all getting a bit antsy about it. Last time we wanted to go, it only took 8 years!
Now, somehow, it’s harder, but NASA also has its sights set higher. It no longer wants to just toddle about the Moon for a bit to wave at the TV cameras. This time, there’s talk of establishing permanent bases on the Moon, and actually doing useful work, like mining. It’s a tantalizing thought, but what does this mean for the sanctity of one of the last pieces of real estate yet to be spoilt by humans? Researchers are already arguing that we need to move to protect this precious, unique environment.