EMP pulse vs car.

[killmime1234]

I've been looking online to see if anyone can definitively describe what effects an EMP will have on a car and so far all I can find is "that it will fry the ECU."

What about the rectifier bridge on the alternator?

What about the starter solenoid?

What about the ignition relay?

What about the ignition coil(s)?

Everyone seems to think that cars that don't have computers are magically immune to an EMP, but I submit that this isn't really the case. Cars have a large number of sensitive electronic components beyond just the ECU. With the exception of cars that have generators (instead of alternators) and are hand cranked to start, are there any cars that could survive and still be working immediately following the blast?

People who know EMP and/or cars, please chime in.

[choprzrul]

I've been looking online to see if anyone can definitively describe what effects an EMP will have on a car and so far all I can find is "that it will fry the ECU."

What about the rectifier bridge on the alternator?

What about the starter solenoid?

What about the ignition relay?

What about the ignition coil(s)?

Everyone seems to think that cars that don't have computers are magically immune to an EMP, but I submit that this isn't really the case. Cars have a large number of sensitive electronic components beyond just the ECU. With the exception of cars that have generators (instead of alternators) and are hand cranked to start, are there any cars that could survive and still be working immediately following the blast?

People who know EMP and/or cars, please chime in.

It depends upon shot placement

[killmime1234]

It depends upon shot placement

Yuk, yuk, yuk.

I'd better specify "Electromagnet Pulse," lest I be the lucky recipient of yet another dry joke.

[Corbin Dallas]

Electro Magnetic Pulse.

I think most solid state devices like alternators would survive if not running at the time of a pulse.

[Dismal_Scientist]

It depends upon shot placement

Glad I'm not the only one that was expecting this EMP when I clicked on the thread

[Joewy]

everything depends with EMP. You never know. However it is the electronics that are affected. Electromagnetic parts such as starters and relays will not be affected. However most alternators have voltage regulators that are microprocessor based. These could be fried. Many older cars have alternators with electromagnetic voltage regulators. These should be fine, So if you have a 1974 VW beetle, Your radio wont work but the car will run just fine.

[corporateslave]

Is it possible that the body of a car would work as a Faraday cage? Shielding it from much of the EMP.

I really don't know much about it but this post on Survivalblog might help:
Real World EMP Effects on Motor Vehicles, by Michael Z. Williamson

[sholling]

I'm not an electrical engineer but the things most at risk in a car or home are the things that can be fried by static electricity - computer motherboards, whether that MB exists in a home computer, smart phone, flatscreen TV, GPS, or under the hood of a car. Outside of a car or home the things that are vulnerable are those that are connected to huge antennas (like the power grid) without benefit of breakers and surge suppression - like transformers.

Alternators, points, and coils won't even notice.

[LMT4ME]

I'm not an electrical engineer but the things most at risk in a car or home are the things that can be fried by static electricity - computer motherboards, whether that MB exists in a home computer, smart phone, flatscreen TV, GPS, or under the hood of a car. Outside of a car or home the things that are vulnerable are those that are connected to huge antennas (like the power grid) without benefit of breakers and surge suppression - like transformers.

Alternators, points, and coils won't even notice.

Not quite true - Back in the sixties the US did a test 800 miles south of Hawaii - Satrfish Prime (I believe). I believe they detonate a nuke about 400 miles up. It took out street lights, garage door openers, security systems. Remember this was be transistors. Soviets did several tests and produced even more conclusive proof that harden systems were vulnerable.

Car is not a faraday cage, 1st its not grounded and second all the electrical components are grounded to the frame. It's a big antenna. Coil, alternator, spark plugs, distributor should be immune i.e. pre 70 car is good to go.

[Pubert]

http://www.youtube.com/watch?v=0odJKYTzXg8

Looks like it will stop the car...

[Alaric]

Is it possible that the body of a car would work as a Faraday cage? Shielding it from much of the EMP.

No, because as LMT4ME pointed out your car isn't properly grounded and those sensitive components aren't shielded within that cage, they're part of it.

You could perhaps park your cars in a shielded underground garage like George Lucas has at Skywalker Ranch for his Tie Fighters and whatnot, but you probably don't have an army of Ewok slaves to build that for you like George does.

The poor man's route might be to keep a spare starter solenoid, generator, fuses and other possibly susceptible components stored in a small faraday cage as a fallback measure. The cheapest faraday cage I'm aware of is an old microwave oven with the ground wire grounded to something other than an electrical outlet, like an actual ground spike. No need to increase the risk by plugging it into an outlet.

[sholling]

Not quite true - Back in the sixties the US did a test 800 miles south of Hawaii - Satrfish Prime (I believe). I believe they detonate a nuke about 400 miles up. It took out street lights, garage door openers, security systems. Remember this was be transistors. Soviets did several tests and produced even more conclusive proof that harden systems were vulnerable.

Car is not a faraday cage, 1st its not grounded and second all the electrical components are grounded to the frame. It's a big antenna. Coil, alternator, spark plugs, distributor should be immune i.e. pre 70 car is good to go.

We're on the same page. Pre 70s cars are safe but streetlights are on that big antenna - the grid. In the early 60s surge suppressors weren't even thought of and transistors weren't all that common. You'd find them in expensive portable radios but the TV and the home stereo had tubes - immune from EMP. I'm old - our first TV was a 10 or 12" console with a gigantic magnifying glass and Ike was still president. A few years later as a 1st grader I lived through the deadly serious cuban missile crisis duck and cover drills and there were very serious doubts that we'd live to see 7. Popular Science and Popular Mechanics etc used to have stories on how to harden your house against the blast and everything from basic backyard shelters to fashionable bomb shelters for the rich and shameless and how you might have to defend your shelter against friends and neighbors. I'd sit on my grandpa's lap and he'd read them to me while I looked at the pictures. He even kept lots emergency rats. In other words I grew up with this stuff.

[sholling]

No, because as LMT4ME pointed out your car isn't properly grounded and those sensitive components aren't shielded within that cage, they're part of it.

You could perhaps park your cars in a shielded underground garage like George Lucas has at Skywalker Ranch for his Tie Fighters and whatnot, but you probably don't have an army of Ewok slaves to build that for you like George does.

The poor man's route might be to keep a spare starter solenoid, generator, fuses and other possibly susceptible components stored in a small faraday cage as a fallback measure. The cheapest faraday cage I'm aware of is an old microwave oven with the ground wire grounded to something other than an electrical outlet, like an actual ground spike. No need to increase the risk by plugging it into an outlet.

The poor mans solution is to find a pre 1974 truck with a coil and points. Unless the blast is close enough to melt the tires odds are it'll start. But keep a spare points and condenser just to be safe. Think about how much power it takes to blow 100 amp alternator or a starter solenoid.

[killmime1234]

Good input guys, keep it coming. I'm gathering that, at least if the people who claim they know what they're talking about actually do, I can count on the starter solenoid and ignition coils to be intact. I'm pretty sure the rectifier bridge for most (if not all) cars that have an alternator is still susceptible since it primarily consists of diodes which are about as fragile as transistors.

What about the ignition relay? It's basically an electromagnetic solenoid, but on a smaller scale than that of a starter solenoid. This one just connects a high voltage circuit when activated. Anybody have any thoughts?

Also, although I'd trust calgunners with darn near anything over the average civi, I'm still curious does anyone have any sources (i.e. books, articles, scientific journals, etc)?

[cjskalka]

Any active component will most likely be toast. It would likely depend on the design of the car's quasi finite state machine. I'm an electrical engineer but no automotive expert so I'm not sure how all the electrical components are tied together. But I would imagine there is some kind of 'safe to start' finite state machine that receives signals from sensors in the brake lines, engine temp, etc that determines its OK to start the car. These signals require a lot of conditioning to maintain their integrity from start to finish which requires a lot of circuity that could be damaged from EMP/EMI. I could be way off but that's how things are done in my industry, I assume its similar for the automotive industry.