I was sitting in the car while it was supercharging the other day and thought that that kind of current could be lethal if something went wrong. Any thoughts about this?
The superchargers are DC(direct Current) with no ground reference. Unless you managed to touch both the negative terminal and the positive terminal which are sealed by the connector, you can't get electrocuted. However, you may get a high voltage static charge when you exit the car base on conditions but this is harmless and is normal for cars. The good thing with the pure EV there is no gasoline near by to ignite with spark from static discharge :-) some people on this board will tell you to get out of the car because of high EMF. Let the flames begin.
EMF stands for Electro Magnetic Frequency. The frequency of DC is zero. Therefor the EMF of a Supercharger is zero.
Actually, EMF is Electromagnetic Fields; however, the effect of such fields is in their variation, or on-off frequency. DC doesn't vary.
Brian - the F is for field. Otherwise well stated.
That would be well and good for a steady state of charge and discharge on the battery. However there is always a magnetic field perpendicular to current flow. Since the current is changing with time as the battery charges the magnetic field collapses as the current decreases creating a varying EMF. This can be measured with a Hal effect device and it looks just like the charging curve of a capacitor, an EMF Pulse.
surely that must be a slow non-periodic change, not able to generate much "collapse" or "varying EMF".
Aren't you glad you asked?
Sorry, I meant dlaprise
If people are worried about the field of supercharging they shouldn't buy the model S!! Supercharging is only 90KW while actual driving it can be over 300KW. Let's get real!
Here's a better way to look at it. Yes, I enjoy sitting in the car at superchargers. Looking at the miles click off at a rate of 207mi/hr just amazes me. (That's what I was getting at Barstow)
If all that power scares you, rest assured, the awesome design of the S also makes for a wonderful Faraday cage;-)
Thanks for the great answers!
Luckily, EMF follows the inverse square law: http://en.wikipedia.org/wiki/Inverse-square_law
So, as you move away from the source of the field (the SuperCharger), the strength of the field decreases by the square of the distance. Also @mthanos, I think (someone correct me if I'm wrong), I recall reading that the motor is shielded to protect occupants of the car from strong EMF, so the risk is reduced while driving.
Just for fun, take an EMF reading from your Microwave, fridge or coffee maker. Even better, an old school CRT monitor. How many hours did you spend soaking up radiation in front of a CRT back in the day? Radiation is delicious :)
Statistically it has to be safer sitting in the car while supercharging than driving it on the road with all those other crazy motorists.
I'd say stay in the car. What you don't want to do is stand by the transformer coming in from the street. lol.
take a pocket compass and see if you can make it pinwheel! At 60 rpm, of course. ;)
Stay in the car... but go to the furthest possible location... the FRUNK ;)