EMF while Supercharging

[BerTX]

The place you connect the car is just a cord holder. The racks of charger units are in the white cabinets behind the decorative screening. So if you sat at a picnic table near that enclosure, you would be closed to the source of emissions than if you were in your car.

Installed units are required to pass FCC conducted and radiated emission testing also.

The car's charger is inactive during supercharging.

Okay, let's recap.

The statement was made that there was hazardous measurable EMF from a Supercharger while sitting in the car. My point was that the same charger that is active while Supercharging, located outside the car is also inside the car.. While AC charging, the same device is active inside the car, so theoretically more hazardous than the Supercharging, if either is hazardous.

The FCC approval is not really relevant to the discussion, since they don't think there is a problem with EMF from most sources.

Thank you for pointing out that the car charger is not involved in Supercharging. I'm sure there are people who don't know that.

 

[mongo]

Model S and Pacemakers

Remember when 7-11s had a warning that there was a microwave on the premises?

 

[malcolm]

However while charging, the EMF increases dramatically beyond what the researchers considered safe and acceptable.

Sorry but no.

As others have pointed out electromagnetic induction requires a changing magnetic field and not the constant one which exists around a cable carrying a DC current.

Inductive charging involves parking the car accurately over a coil embedded in the tarmac. The AC current in that coil induces an AC charging current in the matching coil under the car.

Tesla doesn't use this system (and neither does anyone else)

The only way that you could induce currents in your body while Supercharging would be to step out of the car and dance frantically next to the charging cable (so that your limbs move in and out of the constant magnetic field, simulating a changing magnetic field)

Video please.

ETA: The constant field around a Supercharger cable is nowhere near as intense as the constant magnetic field inside a hospital MRI machine (typically 2 to 4 Teslas - yes the name is also a scientific unit of measurement) and there is no evidence of adverse health effects from MRI unless you have ferromagnetic implants or tattoos containing ferrous metals.

 

[mongo]

Okay, let's recap.

The statement was made that there was hazardous measurable EMF from a Supercharger while sitting in the car. My point was that the same charger that is active while Supercharging is located outside the car. While AC charging, the same device is active inside the car, so theoretically more hazardous than the Supercharging, if either is hazardous.

The FCC approval is not really relevant to the discussion, since they don't think there is a problem with EMF from most sources.

Thank you for pointing out that the car charger is not involved in Supercharging. I'm sure there are people who don't know that.

Original statement (in the context of personal safety at superchargers):

I would first say never sit in the car while it’s charging...especially at high 600v supercharging.

My issue was mostly with the supercharging portion.

IF the chargers emit a harmful energy, then you could be exposed to more of it outside the car than inside while supercharging depending where you, the car, and the equipment are located.

 

[tga]

And it's not "high 600v supercharging" - if you fed 600V into the pack, bad things would happen. Like crossing the streams bad.

 

[FlyF4]

Moderator note (bmah): The first thirteen messages in this thread were split off from a discussion of personal safety.

I would first say never sit in the car while it’s charging...especially at high 600v supercharging.
The amount of EMF in the car jumps tremendously. Similar to your cell phone emissions while charging vs not.

Not sure how to address safety other than charge at home.

My 40 years of electronic engineering experience and knowing the Tesla tells me this is hog wash. Just my opinion.
Frequency, Power, Distance from the source, and what's in between you and the source. Think about it some more. You are welcome to disagree, but nothing changes my mind

 

[FlyF4]

May I add that the OP might have been exposed to more EMF to the penis by the laptop being on top of it during posting than what was theoretically received during a supercharge Yes, this is a sarcastic reply intended to be humorous, so you can laugh..... but SOME truth in the matter

 

[FlyF4]

And it's not "high 600v supercharging" - if you fed 600V into the pack, bad things would happen. Like crossing the streams bad.

Close though... it's 480 volts.

 

[mongo]

Close though... it's 480 volts.

What?
Superchargers are fed 480 three phase, they output pack voltage (plus cable drop) DC.

 

[tga]

Close though... it's 480 volts.

480 AC input into the charger stacks, which are pretty far from the car, or anyone sitting in it.

 

[malcolm]

You don't need google for this. Just simply buy an EMF reader and see for yourself.

Cheaper to do the math.

Magnetic field strength around a current carrying wire just depends on the size of the current and your distance from the wire.

The voltage is irrelevant.

If anyone's interested, the equation is:

Field Strength = Permeability x Current / (2 x pi x distance from wire)

For a Tesla Supercharger running at 150kW and 600V the current flowing through the cable would be 250 Amps but lets quadruple that to a ridiculous 1000 amps.

How far would I have to be from the cable to experience the same magnetic field that exists in the weakest hospital MRI machine (say, 1 Tesla)

Distance = Permeability x current / (2 x pi x field strength)

Works out at two tenths of a millimeter.

You can't get that close to the wires because the insulation is several mm thick.

So even if you sit on the ground with the supercharger cable held between your teeth, it ain't gonna loosen your dental fillings (assuming you have the old type)

Take away: Magnetic fields around supercharger cables are so weak compared with hospital MRI machines, it's embarrassing.

 

[Ketchups]

Magnetic field strength around a current carrying wire just depends on the size of the current and your distance from the wire.
[solve for X here]
Take away: Magnetic fields around supercharger cables are so weak compared with hospital MRI machines, it's embarrassing.

Correct me if I'm wrong but are EMF emissions only limited to wires?

 

[FlyF4]

FlyF4 said: ↑
Close though... it's 480 volts.

480 AC input into the charger stacks, which are pretty far from the car, or anyone sitting in it.

TGA, I am actually agreeing with you. I guess we are hijacking the safety thread a bit. I guess it depends on what is meant by "fed" or "input" into the SCs. Technically, an approximate 700 + kVA utility feed comes into the stacks. A 277 Volt (LN) is pulled from a 3 phase 480Y. Then converted to high voltage DC via high KA Switchgear. So yes, close enough. I think we are saying the same thing.

I might have been misinterpreting mongo to mean that it isn't high voltage DC going to the car, but it is. High voltage DC and high amperage. Apologies if I misunderstood. So back to the safety point... as far as "emf" is concerned, there isn't any at that cable. It's all DC. I'm seeing other posters were equally confused as to why anyone would think this is an EMF hazard.

 

[mongo]

Works out at one tenth of a millimeter.

You can't get that close to the wires because the insulation is several mm thick.

Plus the equation is based on an idealized zero cross-section conductor. The strands themselves prevent approaching that distance.

 

[FlyF4]

Correct me if I'm wrong but are EMF emissions only limited to wires?

NO ! If your microwave is leaking while you are cooking that popcorn, then you will find out that is is also radiated

 

[mongo]

TGA, I am actually agreeing with you. I guess we are hijacking the safety thread a bit. I guess it depends on what is meant by "fed" or "input" into the SCs. Technically, an approximate 700 + kVA utility feed comes into the stacks. A 277 Volt (LN) is pulled from a 3 phase 480Y. Then converted to high voltage DC via high KA Switchgear. So yes, close enough. I think we are saying the same thing.

I might have been misinterpreting mongo to mean that it isn't high voltage DC going to the car, but it is. High voltage DC and high amperage. Apologies if I misunderstood. So back to the safety point... as far as "emf" is concerned, there isn't any at that cable. It's all DC. I'm seeing other posters were equally confused as to why anyone would think this is an EMF hazard.

Yeah, I meant since it is DC to the car (pack voltage under charge plus cable drop) the voltage isn't creating a dynamic field, so the absolute potential is a non-factor. The field being based on the current flow.

 

[barjohn]

Another engineer here and I have never heard of DC induced EMF except when you pull an arc which will cause a brief pulse of EMF. I trust you are switching off the power via the button on the connector before you disconnect it from the car.

 

[malcolm]

Correct me if I'm wrong but are EMF emissions only limited to wires?

In electric vehicles and the chargers and superchargers you plug into them, yes.

Unless you want to sit in front of the front radar unit.

 

[mongo]

View attachment 285562

https://ec.europa.eu/health/scientific_committees/emerging/docs/scenihr_o_041.pdf

I can’t access the full document. One of my colleagues did. I’ll try to get access.

wow 288 pages

219:

Research to date has not been able to identify with any certainty any adverse health
effect resulting from exposure to EMFs at any frequency or intensity typically found in the workplace or everyday environment. Epidemiological studies have reported associations between EMF exposure and certain diseases, most notably for an increased risk of childhood leukaemia with exposure to low frequency magnetic fields, but none of these associations can be considered causal, primarily because of shortcomings of those studies, the lack of support from laboratory studies, and an inability to identify biophysical interactions mechanisms. However, not all areas have been studied to the same extent, and research with some frequencies or modulations is very limited, and this is particularly true regarding new and emerging technologies.

For reference the Earth's magnetic field is 25-65uT at the surface (static, unless you move).

 

[sorka]

Charging and discharging are 2 very different scenarios. Yes I own a Tesla and the amount of EMF during driving and at traffic lights is within acceptable limits. I’ll attach the link to a 2015 study conducted. However while charging, the EMF increases dramatically beyond what the researchers considered safe and acceptable.

And no I’ve never sat in it while it’s charging.

Um, no. What researchers? Safety/health issue due to exposure to high EMF have been completely debunked. When making claims like this, please post your references to peer reviewed journals that are not on the fringe.