A tiny three-phase motor invented by Swiss researchers could be used to power a new generation of wristwatches, allowing them to work as mobile phones, app devices and GPS units. Those activities generally require plenty of power, which can be cumbersome and costly — but a new microelectromechanical system will keep them juiced.
Researchers at the Swiss Federal Institute in Lausanne came up with a small electromagnetic three-phase motor that yields three times the energy output of a traditional motor.
Three-phase electricity works by carrying three alternating currents that reach their peak voltages at different times — so the total amount of power is constant, rather than fluctuating in peaks and valleys like the sine wave of a traditional A/C setup. The concept requires three separate coils to carry the currents. But a triple coil takes up space, which is not what you want in a wristwatch. So EPFL researchers had to build an entirely new configuration.
In a news release, EPFL does not elaborate on the setup except to say that it involved creating an entirely new fabrication process, which can be scaled up to larger volumes. The motor's fixed pieces can be etched on silicon plates, allowing faster production.
The researchers also had to integrate the watch's command electronics with the moving pieces so it could tell time accurately, according to EPFL.
Ideally, efficient three-phase MEMS motors could be used to power a wide range of devices, many more than just cool wristwatches. But these guys are Swiss, so improving the future of timepieces is an understandably high priority.
"EPFL does not elaborate on the setup"? That's probably because they've already published it. Here's all the details:
Merzaghi, S.; Koechli, C.; Perriard, Y.; , "Development of a Hybrid MEMS BLDC Micromotor," Industry Applications, IEEE Transactions on , vol.47, no.1, pp.3-11, Jan.-Feb. 2011
Essentially, they used standard CMOS technology to create six flat, 2-layer copper coils, then floated a tiny ring-shaped permanent magnet over it, about the size of a matchstick head.
who the heck still buys/owns wristwatches. lol
@boka, YEA, your right, everyone knows all the best spies have there phone in their shoe. lol
good job! but a little late. smartphones have rendered wristwatches obsolete.
why learn from your own mistakes, when you could learn from the mistakes of others?
wristwatch tech combined with current smart phone tech will reign supreme in the future.
I guess the real news is the there is a very small 3-phase motor now.
Really I am hoping that this article is being satirical or ironic in some very odd dry way. What function would a 3-phase motor have in a watch? Are they also going to put in a 3-phase inverter powered from the battery.... Ridiculous.
Honestly, I can't think of a single use for this. Neat but useless.
@convictus... That's the main point of multi-phase power: no inverter needed. The time-offset waveforms overlap to provide steady power which is effectively DC output.
It's anything but "useless".
(Ah, the irony of my comment being flagged as spam just two messages below an actual spam post. Great job, popsci!)
@M1.. Unless I am missing something I read the article twice, I think you are incorrect. This isn't a special device, it is just a typical 3-phase motor just smaller.
Not to sound condescending, you can trust me on this I am an electrical engineer, a 3-phase motor is purely an AC device. It takes in 3-phase power on 3 separate wires and outputs mechanical power. The reverse would be a generator.
If you were to tie all 3 wires together to merge all the waveforms the net result would be total waveform cancellation and unless there was a DC bias to the waveform in the first place then everything is *cancelled out.
The reason I stated needing an inverter is because you cannot get AC power from a battery. You can only really get 3-phase power through an inverter or a generator (reverse 3-phase motor). The 'main point of a multiphase motor' is for better efficiency from the hardware.
My main beef with this article was that they said it could be used in a watch. Well possible yes in an analog watch with moving hands but where would the 3-phase power come from? Maybe they are using this motor to power the watch. If so where is the mechanical energy coming from? Are they connecting a DC motor to drive AC motor to provide 3-phase power to the watch? For what purpose? This is the Worst article I have ever read on PopSci... .Ever.
Where this would be useful is in an application where you have 3-phase power readily available and need an extremely efficient motor for very small moving parts. That's it. Can anyone give me examples of situations like this? Anyone?
@Convictus The difference is Electrical and Electronic,in Electronics a single micro chip can be used to generate any type of wave form(from DC),but in Electrical it is dificult due to the amount of power involved..
they are talking about a 3 phase motor to be used in a watch and yes u can have small enough circutery(no inverter) to produce a 3 phase supply for the motor..
Although the picture of a digital watch which does not have a motor is misleading..:)
why, mr. Anderson, why, why do you persist?
Because I Choose To...
@Convictus..."Not to sound condescending"; actually, you sound condescending because you are
@Convictus They keep calling it a motor, but yes, the idea is to run it as a generator. And as M1 mentioned, 3-phase power rectifies much more cleanly than 2-phase, which means smaller losses, smaller or no capacitors needed, etc.
The idea is that your everyday arm movements will generate enough electricity to power your wrist watch indefinitely, without ever needing to change battery. I know this kind of capability is already available in high-end wrist watches, so I assume the innovation is to have a much more efficient, 3-phase motor/generator.
As for those ragging on wristwatches - this same technology can obviously be integrated in all sort of other gadgetry, eliminating the need for most of the battery capacity. Think wearable computing, environmental sensors, nanomachines, etc.
Heck, remember that guy who found a real-life FBI tracking device under his car? Turns out most of it was a big battery pack. Instead, you could take a 3-phase generator the size of a matchstick head, and glue it to the back of one of the wheels on his car... instant power whenever he's driving - no bulky battery pack needed.
@drchuck1.. If I came across that way i am sorry. I did write that because I knew it was coming across that way. I am not an english major I am an engineer and have a hard time expressing my demeanor on forums.
Drchuck don't be a hypocrite though you usually act like an ass on here tbh.
My guess. They're using a free floating magnet to induce current in the coils - arm motion. This current is then rectified, capacitor filtered, regulated and fed to the rechargeable battery.
And, yes, it could run the watch shown.
did anyone see "They Live!"
i want one of those watches