Gov't Researchers Develop Wireless Car Chargers That Are Faster Than Plug-ins (computerworld.com) 169
An anonymous reader quotes a report from Computerworld: The U.S. Department of Energy has demonstrated a 20,000 watt (20KW) wireless car-charging system that offers three times the efficiency of today's plug-in systems for electric vehicles (EVs). The research is the first step in creating a 50KW wireless charging system that may someday allow roadways to charge vehicles while they are being driven. The DOE's Oak Ridge National Laboratory (ORNL) in Tennessee demonstrated the new system in partnership with Toyota, Cisco Systems, Evatran and the Clemson University International Center for Automotive Research. ORNL said the 20KW charging system for passenger cars is the world's highest power wireless system. It was developed in less than three years using a "unique architecture that included an ORNL-built inverter, isolation transformer, vehicle-side electronics and coupling technologies."
270% efficiency (Score:5, Funny)
A Tesla charger has an efficiency of over 90%. If this charger has an efficiency three times that, then it should be above 270%. Maybe it can feed the extra 170% back into the grid.
Re:270% efficiency (Score:5, Informative)
TFA states 90% efficiency at 3x the rate, bad summary is bad
Re:270% efficiency (Score:5, Insightful)
If it charges at 3x the rate, that implies it's ability to pull power is at least 3x what the wired charger is pulling, and it would have to pull that from... a wired connection. This implies the main problem is that the car interface is simply designed to run at a lower power level than this wireless design, and this could be corrected by bumping up the wired interface charge capacity. This is just a case of leapfrogging specs, nothing more.
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Well, not entirely, you do get to use inflexible low gauge wire to attach it to the grid, since nothing needs to flex or bend, and there are no contacts so you can weld everything in place. Those two things may make for a much lower resistance which would mean less need to step the voltage up. Whether the electronics on the vehicle side are heavier or lighter is important, too. If the 90% figure is accurate it is quite impressive. It should probably be asked of them whether that figure is realistic in a
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and how close the charging pad and the 'receiver' pad in the car needs to be.
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This implies the main problem is that the car interface is simply designed to run at a lower power level than this wireless design, and this could be corrected by bumping up the wired interface charge capacity.
Bigger, heavier, less flexible cable ;-)
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Re:270% efficiency (Score:4, Funny)
A Tesla Supercharger charges an empty 90 kWh battery to 80% in 40 minutes. That would be 108 kW, right? And the new wireless demonstration is 20 kW, the first step into creating an unbelievable 50 kW charging system? Yawn...
O, but of course it's wireless, so it will save you a massive amount of time! Sure, it will take an hour and 26 minutes to charge that same battery to the same 80% BUT when you have to connect to a supercharger it can take up to 60 seconds to plug in and unplug! Wireless is obviously better then.
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Sure, it will take an hour and 26 minutes to charge that same battery to the same 80% BUT when you have to connect to a supercharger it can take up to 60 seconds to plug in and unplug! Wireless is obviously better then.
We need a insightful sarcasm mod.
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If only it would actually work for moving vehicles. Right now it looks like a decidedly static setup. Might work for bus stops, but not for highway driving.
Re: 270% efficiency (Score:2)
Most electric cars use about 250 Wh/mile. Driving 60 miles uses 15 kWh, not 50.
10% loss!! (Score:5, Informative)
Yes yes, terrible summary.
The 'fun' part is the 10% coupling waste (versus I would imagine much less than 1% for plugin charging).
Remember, we are not talking about the battery charge efficiency here, their 10% is just for the transfer of power to the car..
So, thats 'only' 2kw continuous loss. Thank god everyone is converting their houses to LED lighting, which still wont
offset the losses here.
Go Progress!
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1% is a bit optimistic... not for coupling loss but for the loss of AC-AC voltage conversion to get across the wire without cooking it or generating insane magnetic fields.
10% is undoubtably worse than the state of the art for plug-in systems, but already better than plug-in systems used to be some decade or so back,
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Why on earth would you think you need AC-AC conversion for a connector?
The battery management is going to take care of the battery charging, and thats a set amount of loss (it doesnt care how the power gets to it..)
The charger unit itself can be designed to produce whatever voltage makes sense to drive the battery controller.
In a direct connection system, that connection will be at that sensible voltage, and believe it or not, to push power (even 20kw)
down a nice fat conductor does not need any fancy conver
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The battery management is going to take care of the battery charging, and thats a set amount of loss (it doesnt care how the power gets to it..)
Actually, like computer power supplies providing DC, that depends on how much power they're using - efficiency varies depending on the load. For example, I've read that Teslas are about 70-80% efficient with a 120V 15A connection, but reach ~90% with a 240V 50A connection.
The losses aren't solely in the wiring, but also in the DC conversion system.
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Why on earth would you think you need AC-AC conversion for a connector?
Standard NEMA connections will do 600V
I think you answered your own question there. Neither house current nor the battery pack's DC voltage will match the higher voltages needed to push power at reasonable currents.
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The loss when charging my Tesla at 20KW through the cable is fairly minimal. There is an 8V drop between the meter and the shutoff switch in my garage over a 100 foot run, but the drop between that and my car going through the flexible wire is fairly minimal, maybe a volt. The cable gets warm, though not uncomfortably so. One of these days I need to track down where the 8v drop is coming from. At 10KW the drop is negligible.
Personally I don't see much need for wireless charging, at least for Tesla. The Tesl
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> Personally I don't see much need for wireless charging, at least for Tesla
Combined with the auto-parking feature, I'd say this is actually a very nice idea. Basically it would mean you would never have to do anything, and the car would always be fully charged. And the auto-park would ensure it was always perfectly aligned.
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It isn't critical how I park my car, and when I pull my car out of my garage there's nothing on the floor when I back out.
And there is the achilles heel of this system In order to achieve any kind of efficiency the transformer connection must be made, and made closely - otherwise you just have an inductor in the floor, and another on the bottom of the car, and warm up the garage.
The electrical physics here is exceedingly simple. yeah, it's a transformer. Where this is going to fail is getting those two inductors close enough. My guess is that they will have some docking mechanism, perhaps a V groove, coupled with grooves or
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2kW continuous loss is much less than the energy that would be wasted on healthcare and funerals for people who accidentally fry themselves on plug-in charging systems. Of course, the current system has problems too: https://www.youtube.com/watch?... [youtube.com]
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No matter how many times more efficient a new tech is; It will never reach or exceed 100% efficiency, because thermodynamics and math say no.
To be 3X as efficient is defined as saying the loss rate is
So at 90% the charger has a loss of L
Thus, if it is 3-times as efficient, then the loss rate is L = 96.66667% * j.
Re:270% efficiency (Score:5, Informative)
A Tesla charger has an efficiency of over 90%. If this charger has an efficiency three times that, then it should be above 270%. Maybe it can feed the extra 170% back into the grid.
The article poster mis-quoted the article. The article actually states: "achieved 90 percent efficiency at three times the rate". So it is the same efficiency as the tesla, but it charges three times as fast.
Re:270% efficiency (Score:4, Informative)
Tesla chargers are 120kW, and the more common CHAdeMO used by the Nissan Leaf is 50kW in it's currently deployed form. So if they can get up to 50kW they will have matched currently available wired technology, except that 50kW is not really enough and will be replaced by 100kW+ chargers in the next few years.
Rapid charging needs to average about 30 minutes per charge to be useful. So that means charging at 1.5C, i.e. 2x the capacity of the battery plus some extra for losses. 30 minutes is the average, if you arrive with 1% charge it will take 45 minutes but most people arrive with at least 20-30%.
The minimum battery capacity for a mainstream vehicle seems to be about 60kWh, which will give you a solid 200 miles range under realistic conditions with some margin for safety. So the charger needs to be at least about 100kW to hit the 1.5C + losses target. That's why Tesla supply 120kW.
This misses the point of wireless charging though. No need to plug in, just install it in car parking spaces and let the car charge for an hour or two while you go round the shops. 20kW is actually already quite adequate for this. I regularly charge at 7kW when shopping.
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I read it, perhaps incorrectly, as the transfer of power from the charger to the vehicle is 90% efficient. Any losses in stashing the power into the batteries would be on top of that? e.g. If the Tesla is 90% efficient with a mechanical connection. And the mechanical connection is close to 100% efficient (which it would need to be in order not to melt?). Then the charging efficiency of a Tesla fitted out to use this would be .0.9 * 0.9 = 81 percent?
BTW what happens to the missing 10% ? Ten percent of
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The real unsurprising story: DOE is developing a method to efficiently transmit 50KW wirelessly - meaning they can boil a 100kg person, wirelessly, in just under 9 minutes:
(100 x 4 x 63 / 3412 = 7.4kW to do it in an hour) https://elementsofheating.word... [wordpress.com]
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Oooh nice. That takes care of ALL environmental issues in one fell swoop! Just boil the drivers! Brilliant! :)
Three times the efficiency?? Not likely (Score:2)
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The article claims the wireless charging system is more efficient than plug-in systems, and since the other comparison was most definitely about home chargers then presumably they're saying that the home chargers are less than 90% efficient at transferring power grid energy to the car battery. They could simply be using more expensive components to achieve the superior efficiency but it could also be inherent in the design since the voltage conversion from wall voltage to car power system voltage is handled
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It would be impossible for a wireless transmission system to reach optimal efficiency at the same point the batteries are at their optimum recharge rate.
That would be the biggest fluke in physics in all of history if that were the case.
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Did you do the calculations to figure this out?
Both wired voltage converters and wireless charging systems use magnetic coupling, the only difference is that the wireless system increased the gap between the two coils and hopefully eliminated several feet of unnecessary and inefficient DC cabling. The wireless charging efficiency drops dramatically over increased distances between the two coils so they probably got them as close together as possible which could be as little as 5.7" for the Toyota Prius, und
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DC cabling is very efficient, especially when you consider the fact that the cabling in a Tesla is designed to handle far, far more power. Power loss in wire is non-linear based on current, it's basically (I^2) * R. The loss in the flexible cable going to my Tesla loses less than 1V at 20KW. The cable gets a little warm, but it's still quite comfortable to touch. If there were significant loses anywhere near the loss due to wireless charging then UL wouldn't approve it. It would turn the copper cabling into
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What voltage is your Tesla receiving power at? If there's a 1V drop at 120V that's not too bad but if it's at 12V that's nearly 10% of the power output by your charger which has it's own inefficiencies. I suspect Tesla is particularly smart with their charging system so it likely surpasses most other charging system's in efficiency but the fact remains that there's power loss in the cabling that may not be exhibited by a wireless charger that's much closer to the batteries in the car.
I've assumed that the 9
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It charges at 240V, so under 1v is under 1% loss. I doubt there's any noticeable loss at the connector since it is designed to handle far more current when supercharging. The inverters for charging the battery are also probably quite efficient, probably over 95% and more like 96-97% efficient. The wireless charging would be in addition to the normal losses. The incoming AC would need to be converted to DC, then converted back to AC at a higher frequency. Then there are the losses involved in the energy tran
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> What a waste of our tax dollars.
I think perhaps they are viewing this as a step toward a world where, for example, chargers are buried under bus stops and when a bus stops to load/unload passengers, it also takes on a load of electrons. Chances of that eventually working once about 50 other problems are solved? Who the hell knows? Not terribly high probably, but clearly not zero.
Probably a better investment than an F-35. And much cheaper too.
Interference potential (Score:4, Insightful)
Can't find any clue as to what frequency is being used for the charger. The prospect of 50 kW of power in your garage or wherever is worrying, despite being "well shielded". Even if it's a lower frequency (in the kHz range), there will be harmonics all over the spectrum, putting radio amateurs and anyone else using sensitive radio gear in a bind.
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“We've arranged a global civilization in which most crucial elements profoundly depend on science and technology. We have also arranged things so that almost no one understands science and technology. This is a prescription for disaster. We might get away with it for a while, but sooner or later this combustible mixture of ignorance and power is going to blow up in our faces.
Most people don't know the difference even on a supposed tech site. If they don't get it here, what hope is there for the rest of the people? I know people wth engineering degrees that don't even get this/
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Not to mention if you ever did manage to sink that much power into your cell phone it would likely melt, require a beefy alternator and it would significantly affect your gas mileage.
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At 50KW? Never mind radio amateurs - you'll need a 'no pacemakers' sign on the garage.
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sloppy summary (Score:2)
The wireless charging system is not faster than all plug-in chargers, just the ones commonly used at home. The charge stations available commercially are faster and the article mentions this. It is also not three times more efficient, it's 3x faster than the home charging systems. It's 90% percent efficient, which is impressive but I seriously doubt any charging system is only 30% efficient.
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This is great news (Score:2)
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You do realise that inside many DC-DC converters, and indeed inside all of the power transformers between the power station and your house, there are magnetically coupled coils that effectively transfer the energy "wirelessly".
The difference in this case is using an air cored coil at a greater distance. It's definitely harder to make them efficient but they have clearly shown great potential here, with 90% efficiency versus DC-DC converters at 95% and regular transformers at 98%.
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Any loss of efficiency with an air core is not do to loss within the air itself; the problem is that the lower coupling means higher circulating currents in the coils for a given power and the lower inductance means higher frequency operation. You can get better efficiency using a traditional transformer at a lower cost and if the existing efficiency is lower, it is just because of economics.
Extremely dangerous (Score:3, Interesting)
The actual picture is pretty funny, with a ginormous briefcase put under the back of the vehicle, a mere 2 inches above the similar unit embedded in the floor. No way is that remotely practical, they would need to increase the air gap by at least triple, to 5x+ to properly mount it under reasonable vehicles. To keep the same coupling, the size would then have to be increased substantially. Further there is no way in hell that is working while you drive, it has to be precisely aligned which isn't going to happen period, even at stoplights. I could see it embedded into a garage stall, or even a parking stall outdoors, perhaps, but alignment would be a major issue and one that is not being addressed at this stage from anything I can gather.
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There was an old rule-of-thumb in the electrical trades. A million volts won't do anything, but an Amp will kill you.
And it's one of those sayings with a grain of truth in it but which misleads more than it helps.
What actually matters is the current through the body. As a general rule in power systems, a higher voltage means a higher current through the body, the operating current of the system is mostly irrelevent.
I'd hate to see the safety guidelines on a 20,000 (or 50,000) watt connector.
On a three phase system with 230V from phase to neutral and 400V from phase to phase 20kW is about 30 amps per phase. 50kW is about 72A per phase. That's within the range of normal industrial plugs and sockets.
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A nine volt battery is enough to kill you.
Do this test: Put a needle through the skin on both of your temples. Attach a wire to each needle. Attach the wires to a 9 volt battery's terminals.
If you don't tell us how it goes I'll just assume you died.
Your skin has fairly high resistance, but get through that and you're playing with fire.
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This is a prototype. The most likely configuration based on current technology will be a receiver that is flush with the current vehicle undercarriage - no lower than it is now.
In the charging area, there would be clearly painted lines or perhaps even ruts, to ensure the car was aligned perfectly with no chance of hitting the transmitter.. The transmitter would likely have a system that automatically raises it into the proper position vertically.
The concept of charging on the highway was described as future technology based on the current technology. They clearly consider this to be a continuing research product, not an end stage, ready for consumer device.
However, all that raising and lowering is insanely expensive, requires moving parts and greater complexity which all undermine the notion of wirelessly transmitted power. At that rate why not just have a plug that lifts up from the ground and cut the costs by a factor of 10, the power losses by a large amount, and the charge time by another factor of 10.
Given their current technology and the rate of advancement, it is not unreasonable for them to widen the gap sufficiently and to enlarge the charging field enough to allow in car charging while cars were in the correct lane.
Except physics yes. The fundamental laws of physics wont change and the coupling efficiency is massively dependant on the gap to width ratio. Simply pu
Not even wrong (Score:1)
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Have you been reading the prospectus for my IPO?
Hmmmm.... (Score:1)
Why is gov doing corporate R&D?????????? Why are tax dollar being spent to improve the profit margins of a select group of companies???
In soviet Russia.... (Score:2)
Cherry picking numbers (Score:3)
Home chargers for Tesla offer 20kw (22kw in EU) for usual setup.
Superchargers offer a lot more - 135kw for Tesla superchargers, 50kw for regular EU charging stations.
3 times the plug-in charger rate is incorrect (Score:2)
Tesla Model S was the best selling EV in the US last year (yes, it outsold the next best - the Leaf, in number of units, not just sales $) - source http://insideevs.com/monthly-p... [insideevs.com].
Typical home charger for a Tesla is the mobile connector which delivers 10KW charging from a dryer outlet. Owners have an option to install a 20KW Tesla plug-in charger in their garages, which many people do. Tesla plug-in "superchargers" charge up to 120KW, so 20KW wireless is not 3 times the rate of any of those plug-in charge
Requires MV primary coil (Score:1)
Of course it's faster, because with inductive charging systems you can build it in such a way that it can use a 13.2kV primary coil without putting anyone at immediate risk of electrocution.
The limiting factor in plug-in systems is the 240V supply rail, which is limited to a 30A circuit breaker (240V * 30A = 7200W). If you pipe in a higher voltage primary to a plug-and-socket, then you introduce issues of arc flashing and electrocution. However, if the primary high voltage coil is safely isolated and couple
Why the obsession with wireless charging? (Score:2)
The reality is that electric vehicle owners equip the place they park their car overnight with a high capacity electrical circuit. It takes less than 30 seconds to plug in the car after you park.
Doubtless a wireless charging solution could be made safe and effective, but it would cost more. We don't need to find ways to make electric vehicles more costly.
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The problem is that, even at 7.2kW (maximum available power from a home circuit) it will still take several hours to charge even a modestly-sized eCar battery.
As I outlined in another post, using a higher voltage supply increases the available power, but this cannot be done very safely with a plug and socket system where contacts are made and broken. There is a risk of arc flash any time a high voltage contact is broken.
Have you ever heard something spark when you plug something into the wall, or unplug it?
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For long range driving trips in an electric vehicle, I see no practical charging technolo
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The problem is that, even at 7.2kW (maximum available power from a home circuit) it will still take several hours to charge even a modestly-sized eCar battery.
As I outlined in another post, using a higher voltage supply increases the available power, but this cannot be done very safely with a plug and socket system where contacts are made and broken. There is a risk of arc flash any time a high voltage contact is broken.
Have you ever heard something spark when you plug something into the wall, or unplug it? That's a small arc inside the socket. At 120V or 240V household voltage, they're pretty small (but can be much worse under abnormal circumstances). The higher the voltage, the larger and deeper a plug and socket must be to contain the arc, and the less safe the whole thing becomes.
Removing the make/break operation from the process increases safety by orders of magnitude, and allows much higher supply voltages to be used, therefore increasing power and decreasing charging times.
It is not uncommon for modern Lithium batteries to be charged at 1-2C. A 25kWh battery could be charged at 50kW CC and probably even finish its CV cycle, all in about an hour.
I think this also makes more sense for a mall or office parking lot. I imagine it would be a hell of a lot easier to just put a wireless charger in each stall and not have to worry about the connectors being damaged by humans connecting and disconnecting their vehicles than to build a charging station w/ the appropriate plugs at hundreds of stalls. Instead, you supply a nice steady stream of power while the user works / shops.
Beware totalitarinism (Score:3, Insightful)
This is awesome news, but there is a threat here:
I'm fairly certain, that future technology will not allow anonymous charging. It could, but it will not — for the same gratuitous reasons you can't use and recharge a toll-paying transponder anonymously (the way you could use a phone-calling card, for example), but must associate it with both yourself and your car. (Well, New Hampshire, sort of [ezpassnh.com], makes it possible to avoid providing your name, but the cars must still be listed in advance.)
And it is increasingly impossible to drive in certain places without such a transponder [paturnpike.com], which is, of course, routinely used for surveillance [aclu.org].
As happened with electronic toll-paying, the on-the-road charging too will go from optional to mandatory. Manufacturers will reduce the battery-sizes in many models to save weight and space — and how much of a charge do you need to get from the powered highway to your home (over unpowered streets), right? Effective tracking of your car will become possible. Worse, it may also become possible to remotely disable your car by revoking your access to these chargers.
Today's concerns over license-plate readers [aclu.org] may then appear naively quaint...
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The cost... What about the weight and the bulk? I love the possibility to lay the rear seats flat in my gasoline-powered car — a luxury electric cars do not afford, as far as I know...
Yes, it may turn out that way. But if, as the write-up suggests, such charging is implemented, it will come with the privacy risks I fear...
not the barrier to entry (Score:1)
I'm avoiding them because of cost and distance limits.
Another non-problem solved by tax funded research.
Re:Wireless charging is probably dangerous (Score:4, Insightful)
There's an abundance of research showing that strong electric and magnetic fields can be hazardous.
No there isn't.
It's also been shown that too much exposure [to MRI] causes cancer.
Total BS.
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It's also been shown that too much exposure [to MRI] causes cancer.
Total BS.
Then why do radiologists always stand behind lead-lined walls/glass when they operate the machines?
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I think they usually monitor the procedure in real-time, adjusting the area being scanned, etc. I can't imagine why having a computer in the same room as a 1.5T superconducting magnet would be a bad idea...
Re: Wireless charging is probably dangerous (Score:5, Informative)
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You're confusing an MRI (Which uses magnetic fields and non-ionizing radio waves) with a CT scan, which uses ionizing x-rays. Lead shielding is used for devices that emit x-rays.
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Then why do radiologists always stand behind lead-lined walls/glass when they operate the machines?
Radiologist doing MRI do not stand behind lead lined glass. The reason they stand outside of the imaging room is to keep sensitive equipment (computers) out of the magnetic field and prevent random pieces of metal in their pockets from accelerating towards the patient. You must be mixing MRI (magnetic resonance imaging, which uses nuclear magnetic resonance) with CT (computer tomography, which uses relatively high intensity X-ray).
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There's an abundance of research showing that strong electric and magnetic fields can be hazardous.
No there isn't.
OSHA Links to Dangers of RF radiation [osha.gov]
High powered consumer microwave ovens output about 1kW the charging device uses 20kW. There is serious risk of getting an RF burn from this thing.
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"No there isn't."
Yes, there is. This is why hospitals demand you remove all metal objects ND INFORM THEM OF ANY INSIDE YOU before you go into an MRI/CT scanning machine.
I've had a steel under-skin stud piercing ripped out of my body from an MRI, which also damaged the machine. Try again when you've actually experienced this shit first-hand.
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Many types of stainless steel are non-magnetic.
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They should have made you pay for the damage. Did you think being under your skin made it different somehow? I know they told you to remove all metal.
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If you're in the way of microwaves that are too powerful, you'll cook. If you're in a magnetic field that's too powerful, metallic things can be ripped from your body or thrown into you. Those things are pretty obvious, and not what people are talking about when they say those things are safe.
Re:Wireless charging is probably dangerous (Score:5, Informative)
Who said a MRI is dangerous? Thousands of people have them every day with no increase in cancer risk.
If you bring a large chunk of metal in to the room then sure it's dangerous but that's more to do with the metal flying physically towards a magnet rather than cancer.
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As long as there is a properly installed quench tube to vent the boiling Helium and prevent it from filling the room, I don't see how a quench can kill or injure someone.
What would make sense is that someone went near the scanner with something magnetic, injuring/killing themselves or someone else, and resulting in an emergency shutdown of the field (i.e. a quench).
Alkaline batteries are dangerous too, if I eat them.
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It would not need to be "magnetic" ( assuming you mean ferrous ), only conducting.
An aluminum bolt/rod/whatever in your person would still conduct, and moving thru a magnetic field, would have current induced in it.
That current, having nothing to do, would likely heat the component in question.
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I should have said ferromagnetic. Anyway, the point is, the quench itself likely didn't cause the injury, but was initiated as a result of it.
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Who said a MRI is dangerous? Thousands of people have them every day with no increase in cancer risk.
I don't know about cancer but MRIs are not harmless. People have been killed/injured by magnetic quench and RF heating of undetected foreign material.
When and where?
Re:Wireless charging is probably dangerous (Score:4, Funny)
There's an abundance of research showing that strong electric and magnetic fields can be hazardous.
Sure, like the electric field formed between clouds and the Earth, but only if you happen to be around when the field discharges.
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And yet none have been able to identify the powered devices in double blind studies.