Prius EMF Radiation and Toyota's bold face

I think at times, the astroturfers expect us all to be tree hugging hippies and are terribly shocked to discover the number of techno weenies here enjoying a high tech car. It is like assuming that Prius owners are liberals, it can bite you pretty fast. (I am a liberal tree hugger*, and am not trying to insult them, just point out there are other reasons to be a Prius owner)

I am not sure the OP was an astroturfer, they may have been a single issue advocate (like anti-vaxers, birthers, etc.) trying to lead us to their single issue. Sadly for them, Toyota has shielded all the Hybrid specific stuff well, and the high points of EMF in a Prius are the normal ventilation fans any car might have.


*Wild Olympics Campaign

 

Good info, also the sheetmetal of the car has to be takened into account to providing shielding.

DBCassidy

 

I have only been involved in testing computer equipment for EMF radiation. Have you had the opportunity to survey a Prius for EMF and what did you find?

If you have not, perhaps these folks can be of assistance.

www.swri.org/4org/orghome.htm

 

For the purposes of your argument, my career in electrical engineering, including some actual EMF / EMC / EMI testing of real products, makes me equivalent to Big Tobacco. Therefore you may want to dismiss my responses out of hand, along with all the previous discussions here. But ...

I understand how the M field comes through the aluminum block, but how does the E field come through? And how does the wiring in your house walls get shielded at all?

Under my hood, inside that orange cable sheath, is a metal mesh shield. Is this missing from your car?



To repeat part of my earlier reply:

This has been discussed ad nauseum, and the Prius EMF has been found to within the range of other cars -- some others are better, some others are worse. The cars with stronger EMF have not had that linked to occupant problems.

Do you have any reason to suspect EMF over more mundane factors such as poor seat fit, cockpit ergonomics, or air quality?

 

I do not think facts will sway him, they did not work before. He wants to grind his axe and spew his FUD.

 

he'll turnip agin around november 15th.

 

A bunch of us, including me, are engineers who work with electromagnetic fields. I'm not as active as others who post here, but I've occasionally shepherded major telecommunications systems through EMI (ElectroMagnetic Interference: That is, what the system under test does to electromagnetic systems around it) and EMC (ElectoMagnetic Compatibility: That is, what other electromagnetic systems can do the the system under test.)

For those of us who do this kind of thing, that doesn't make us perfect: But when somebody shows up spouting stuff that claims that water falls up, you might imagine that person gets short shrift. Those of us who do this and understand the material (which we had better be able to do, otherwise we couldn't do our jobs) are also aware that the general public doesn't have a good feel for EMI/EMC. And we really dislike people who spout garbage that rather looks like it was designed to mislead the general public. You may call that a "smug attitude". I call it impatience and suspicion. Of you.

Right. So, you're equating the paid-for-by-the-tobacco-industry so-called scientists who shoveled doubt and garbage for decades when the industry's own doctors knew that tobacco was a killer. When reputable research scientists, in much larger numbers, were printing papers to the contrary.

I live and work in the industry. You'll have to take my word for it, but I have never run into a manager of any kind who pressured me or anybody I knew to suppress safety information. Quite to the contrary. And I simply am completely unaware of any reputable study that states that the kind of EMI/EMC from a Prius, or any other car, could cause problems.

First bullshit statement. You want to die? I'll take a 5-W kylstron oscillator, connect it to a bus inside the computer, cut a hole in the side of the computer, cover it with the same color plastic, mount the klystron on the inside, and you'll die of being cooked, just like a microwave. With microwaves. That being what klystrons do.

It's not the amount of power: It's the frequency and amplitude of the signal that hits you. Hey, let's play a little fun: PC's run with multi-GHz CPUs and other hardware. That's microwaves or close enough to make no difference. Why aren't people dropping like flies? BECAUSE WE SHIELD THE STUFF. And there are standards out there that require this stuff be shielded.

So, what frequencies are the in Prius: First, major power distribution in the Prius is by DC. Guess what? DC doesn't radiate worth a damn. You do get magnetic and electric fields: But, when you run the power distribution wires (+ and -) next to each other, as Toyota does, the E fields are concentrated between the wires and the far-field (i.e., inches away) magnetic fields cancel. You can see the DC power from the battery going into the inverter: That's the one that appears not to have a metallic ground. Reason why: It's not needed.

Second: Switching frequencies of the motors. Point #1: all the good, high-voltage, high E-field stuff is inside the inverter. Which is metallic. Distribution wires: You see it in the picture above: Those are the ones with the metal braid. Point #2: We're talking 100's of Kilohertz. Guess what? Unless you have a couple of hundred feet of exposed wire, this stuff really doesn't radiate. In fact, you'll notice that the braid in the above picture has lots of holes in it. At GHz, those holes would allow signals to pass through without a pause. At the 100's of kHz that the Prius operates at, that holey braid does a wonderful shielding job.

Yeah. You betcha. And this is garbage statement #2: House wiring isn't shielded. The Prius wiring is. And, as I mentioned before, placing the wires cheek by jowl with each other results in self-shielding with regard to the magnetic fields. The electric field is taken care of by the braid.

Right. OK, time to introduce you to the world around you. World, meet poster. Poster, meet world.

If you look at something metallic, you'll notice that it is, in general, shiny. And shows reflections. Have you ever thought of what this actually means?

Pure metals have one (mostly) or sometimes two electrons in the outer electron shell. Said electrons are not well attached to their originating atoms and flow around. Easily. Those of us who muck with this kind of stuff call it an Electron Gas. So, you got all these negatively charged electrons charging around at high speed. This is, by the way, how you define a metal: It has this electron gas. If it doesn't, it's not a metal.

Now, hit this electron gas with a electric field that, transversely across the surface of the metal, is, say, positive on the left and negative on the right. Think about that. Negatively charged electrons will charge towards the positive side of the field and away from the negative side. Next trick: A moving electron creates an electromagnetic field itself. This effect is called counter-EMF.

Now, put an EMF field with a sine wave of electric field and dump it onto the metal surface. The electrons will move in lock-step, creating their own EMF field that pretty much cancels out the impinging EMF field at the surface of the conductor. (Since the electrons are attached, a little, to the atoms in the material, and don't have infinite density, there is a little penetration. This is called skin depth. At 100,000 Hz, it would be measured in tenths of a millimeter or less.) In the process of doing this, it generates an EMF field that moves away from the metal at ye olde Speed Of Light.

Hello: And that's what a reflection is. And why you see your face in the mirror in the morning. That's the electrons bouncing back and forth at the Terahertz rates that optical EMF fields have. Hundreds of KHz in a Prius? No problem. Silver is the best room-temperature conductor, copper is #2, but aluminum is plenty good enough for house wiring (although there are issues with corrosion that put the occasional burning house into the news) and just fine for shielding.

Next: If an EMF field moving at Ye Speed Of Light hits a shielded (metallic) surface, the field is cancelled and reflected at the surface. So, exactly what gets through the metal to the other side? Answer: Nothing does. Or, given that we've got a braid there, a little does. Likely attenuated by factors of 100,000 or greater. At frequencies that don't radiate without wires hundreds of feet long. Result: It's not going to hurt a human. Or a fly. Or an elephant. Or anything, really.

Cast aluminum? Sure, why not! It's good stuff for the purpose. And probably better than iron or stainless steel, both of which aren't as good conductors as aluminum. So, your statement: complete and utter bullshit.

So: Why did I take all the time going through all of this?

1. People who don't know beans about EMF are going to read this thread and think that your stance might have some validity. Just hearing, "Aw, it's all garbage" from the cognoscenti sounds a lot like the tone that you take. So, all of you newbies to EMF: Those of us who have met Maxwell's Equations really don't agree with this poster's tone and think that several of his statements are not just wrong, but are dead wrong. Like claiming that rocks spontaneously fall up, or that the Earth is held up by elephants.
2. You might learn something. Unlike biology and cigarettes, where cause and effect are hard to directly observe, the physics of electromagnetic fields is well known. If there are EMF causes to various malaises as reported by some observers, those pathways, and effects, have not been shown by any reputable, repeatable study to this date.

Heck, I've probably fallen victim to a troll.

KBeck

 

Education. Its a beautiful thing.

 

I had problems with my lower back until I raised the driver's seat to its highest position. As the seat cushion rises, it also tilts back. The default position is really uncomfortable. If people are having back issues they should try this. Even though I'm almost 6 feet tall, there's still plenty of headroom, and legroom below he steering wheel. I did have to push the seat back as far as it will go.

 

I've enjoyed reading the educational posts by Jonny Zero, HTMLSpinnr, fuzzy1, kbeck, etc.

I'm a little shaky on the Internet lingo. What is an astroturfer? Does FUD = fear, uncertainty, and doubt?

 

Many groups are 'grass roots' organizations, formed from the bottom up by concerned individuals, Mothers Against Drunk Driving might be a good example. When you discover a groups that appear to be independent, but are financed by some company to LOOK like a 'grass roots' group, they are fake grass. Astroturf is fake grass.

If a company wishes to compete with the Prius by making a better car, we are all in favor of that, but when they hire someone for spread Fear, Uncertainty, and Doubt, (FUD) as is sometimes the case (crazy studies 'proving' that a Hummer is more ecological than a Prius, wild claims about EMF which not supported by any science, hired GM shills back when the Volt was in theory, so we had no hard facts to ridicule them with, etc.)

 

Astroturfing - Wikipedia, the free encyclopedia.

Yes on the latter.

 

Just a couple of things you might bring to the discussion:

You might get a field strength meter and take measurements to document how much "receive more EMF" you are receiving. A simple Google search shows they range from $25 (MFJ-801) to $650 (Extech RF EMF Strength Meter.) The more expensive ones handle higher frequencies in the microwave region. This will give engineering units instead of the imprecise "very very tired" meter. In contrast, I find the Prius lower vibration and noise levels has converted my conventional "very tired" feelings to just "tired" allowing me to drive 14+ hours without feeling beat up.

Of course you'll want to take these measurements in a shielded room. An ordinary aircraft hanger with all power off would do. There are also places where:

Source: Are the 'Wi-Fi Refugees' Really Sensitive to Radio Waves? | LifesLittleMysteries.com

On the second point, it is inaccurate to cite the maximum voltage and current without showing the ranges of voltages and corresponding current. For example, there are three versions of Prius traction batteries:

	Column 1
0	[th]battery V[th]multiplier[th]max A[tr][td]273 V[td]1x[td]70 A[tr][td]202 V[td]2x[td]100 A*[tr][td]202 V[td]3x[td]100 A*[tr][td]144 V[td]3x[td]100 A*

* - estimated based upon available electrical power
As the voltage is doubled and tripled, the current is cut in half and a third. My measurements of the 2001-03 model, 273 V battery, shows a maximum of 70 A. The later models have higher current flows but once it goes through the voltage multiplier, the current is proportionally reduced.

Addressing the third point, the outer, weather proof cover is orange plastic and covers a fairly thick, aluminum shield. Take a hacksaw to your cables and you can see the cross section and solve the "very, very tired" feelings.

Bob Wilson

 

You've got to be kidding me? I have put over 170,000 miles on my 2006 Prius all over the country (once 22 hours straight through to Las Vegas). Do I get an 'out of the ordinary sensation when driving my Prius'? Well, yes, I do. It is a feeling of exhilaration! Knowing that I am getting over 3 times the milage as I was when I used to drive Chrysler mini-vans all over the country. Even more vigorating now that I can play and experiment with my new plug-in Prius.

 

Ah ha! We have a diagnosis:

You have "electromagnetic hypersensitivity" which is described:

Source: Electromagnetic hypersensitivity - Wikipedia, the free encyclopedia

In contrast, Prius owners are "Electromagnetic_stimulative", we are energized by EMI fields. For example I was at a local WalMart and looking in a mirror found that many of us look like:

Well at least tonight*, October 31, we do.

Bob Wilson

* - All Hallows Evening

 

I used to take 4 hr trips in a 1982 Dodge Charger 2.2. When I got to the end of the trip I felt like I'd been beaten up.

The Charger died. I purchased a plush pickup truck. At the end of 4 hr trips it was like I'd been snoozing on the couch all the while.

The problem was the vibrations from that tiny, tinny little car. Perhaps the OP had too much air in his tires. Or, most likely, if not an actual troll, his tinfoil cap was not grounded properly.

 

Jimbo and cwerdna, thanks for the explanations. I've heard terms like shill and troll, but not astroturfer. It makes me wonder how many companies and lawyers like to fuel the FUD so they can benefit and profit from it. No, I don't believe every poster is secretly on some company's payroll, but it's quite plausible that people might try to influence the industry for money.

 

I'm also 6' tall and although the seat base is more comfortable at the highest setting, I found myself craning my neck down a lot to see signs and traffic lights in the city, leading to shoulder and neck pain. Also the steering wheel doesn't telescope or raise enough to make it easy to get my knees in and out of the car at the high seat setting. I think the reason for feeling tired in the Prius is because it's such a relaxing car to drive and the seats, although not the best, are pretty comfortable.
As for the EMF, I find opening a window now and then lets enough EMFs out so as not to make me tired

 

I think there really may be something to all this. Look at me when I got out of the car last night.