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That is good to know. Thanks.
I am still confused as to what voltages the European Model S supports for IT, TN, and single phase, and where these voltages are measured.
GSP
Correct. The transformer midpoint is connected to real ground via a spark gap. Each building is directly connected to ground via ground electrode. Only the phases (three wires) are connected to each building. So we don't have any N wire back to the transformer, only L1, L2, L3. A three phase cable for IT has L1, L2, L3 and PE.
The label says it supports three phase at 400 V, and that it's only for IT grid use. That's actually impossible. If you have three phase (like most), then you have 400 V TN or 230 V IT, never 400 V IT.
My understanding is that three phase at 400 V TN, single phase 230 V TN and single phase 230 V IT are all supported, but not 230 V three phase IT.
Almost correct. Owners with 230 V IT three phase can purchase a transformer to provide 400 V TN three phase.
I believe no customers have tested 230 V IT three phase yet, but the adapters Tesla provides (err, will provide "in a few weeks") are 230 V, 32 A single phase and 400 V, 16 A three phase, I think. They have also said multiple times now that 230 V IT three phase is not supported.
Three phase voltage is always given as phase-to-phase, never phase-to-neutral. Single phase voltage is given as phase-to-neutral for 400 V TN systems and as phase-to-phase for 230 V IT systems. So 230 V three phase IT has a phase to neutral voltage of 133 V, and this is never used except in wye connected three phase equipment.
Tesla also ran into some trouble with supporting single phase IT, because we don't have L, N and PE wires. We have two lives, both at 133 V potential to ground, and PE. It seems that the Euro UMC expects one of the pins to be neutral wrt ground and throws a fault when connected to a single phase IT outlet. So they had to make a special UMC for Norway. I think our UMC works in Europe too, but that the Euro UMC will not work in parts of Norway.
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I think it's being made too complicated in trying to account for all of the electrical system differences.
The Tesla chargers seem to have 2 requirements, whether US or EU:
1. The voltage provided across inputs to the charging unit (charger in the US or phase-charger/sub-charger in EU) be between 85 and 277 VAC with best operation at ~240VAC (I imagine similar in EU). EVSE's like the UMC may have different ranges (I note the one above shows 200-260VAC). How the voltage is derived is not an issue; whether it's 120V L-N of a 240V/120V center-tapped split-phase, or 120V L-N of a 208Y/120V 3-phase configuration, or 208V L-L of a 208Y/120V 3-phase configuration, or 240V L-L of a 240V/120V center-tapped split-phase, or 277V L-N of a 480Y/277V 3-phase configuration (this one Superchargers use). There are other exotic configurations (high-leg of delta system) that I don't believe anyone has tried yet. If you can provide a voltage somewhere in that range and the capability of carrying the current, the Tesla can use it.
I believe that this means the Model S cannot use 400V+ L-L voltages - although it works on 400V+ L-L SYSTEMS because the voltage used is relative to the N - they rely upon another conductor of some sort (e.g., a wye neutral) to supply a lower voltage.
I agree. I also suspect for single-phase (whether IT or TN), Tesla will use an adapter to connect L1 of the supply to L1 on the charger, and L2 of the supply to N on the charger; this is why 230V IT and TN will work single-phase, but not three-phase. For 3-phase 400V TN, it will be connected as below.
2. The second requirement is that in the US, the Tesla UMC must see a stable and constant voltage of one of the line conductors vs. the earth ground, or it will display an error and refuse to charge.The second requirement is likely what's triggering a special charger in Norway for the IT grid, and it's precisely why portable generator charging is problematic in the US - many portable generators float their outputs relative to the earth/safety ground and they're not bonded.
I'm not so sure this is the case - perhaps there is some EU regulation which requires it, but I would be willing to bet it's more of the case that the IT grid floats relative to ground without bonding. In the US, we have some cases where there is different potential of neutral relative to earth in more complex systems.
This is what I suspect the charging infrastructure looks like, based on the information that we have:
(The neutral bus could be inside the chargers, too. Don't take it too literally, I used a simple paint program.)
In this architecture, each subcharger can operate at 200-260VAC, which would give it a 3-phase L-L voltage range of 346-450V. Since it's a completely balanced load, we don't have to worry about the side-effects of 3-phase imbalance.
Finally, for what it's worth, in the US we list a three-phase system based on L-L voltage and add L-N voltage if it's a wye, e.g. 480Y/277V or 208Y/120V. Tesla lists the L-N voltage because that's the potential it's using in the chargers. I guess we can have philosophical arguments as to whether or not Tesla could multiply it by 1.73, but it would likely only be important to EE's. Most standard appliances you use are in the 230V range anyway, so equating it to common household appliances is likely the best move. Just my opinion, though.
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You know much more about that than me, I bet you're right
This is a bit interesting, because it shows how ingrained our ideas of how the world should be is
This is exactly what we've been trying to explain for years, and what Tesla didn't get: In Europe, 400 V three phase is a common household voltage!
Every farmer, mechanic and carpenter knows perfectly well what 400 V means - that's a big, red plug that packs a heavy punch, the kind you use for garbage compactors, circular saws, building dryers, hydraulic presses, mobile lifts, concrete mixers, welders, you name it. They likely don't have a clue what the square root of three might have to do with electricity, though. If you live in Sweden or Germany, you probably have a three phase kitchen stove.
No one knows what 230 V three phase is, except Norwegians and TMC members who read this thread. And those are likely to think you're referring to that backward Norwegian system, not ordinary 400 V :biggrin:
Tesla should use the common term that everyone knows, and that is 400 V. If they find a way to support 230 V IT three phase, then that should be referred to as 230 V, three phase, not 133 V three phase.
But again, this is nitpicking, what really matters is that the car works with three phase power
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I quote myself... If someone here that has an European Model S can lift the cover of the back seats... Just to be sure
A Norwegian MS recently charged at 16 A from a 32 A Type 2 pole. So it looks like the twin chargers will deliver 22 kW, as expected.
Just for the record, the US chargers can deliver 22 kW as well, it's just that very few people are going to have access to 277V L-N on a 3-phase 480VAC system. The US chargers are rated for up to 277V (at least their sticker says so), which would allow for 22.16 kW @ 80A. Tesla just simplified to give us round numbers.
I see... As expected :/ Thanks for the info.
Also good to know that the upper limit ia rated at 277 V... But for me it'd be nice to know the lower. Trying to charge at 220 V L-L 3 ph. (125 V N-L) would be interesting, as is exacty what I have at home.
For US chargers, I've been told it's 85 VAC. It obviously works at 120VAC in US homes. Not sure about the EU chargers though.
Then you need an EVSE that will work; it appears from Tesla's specs that the UMC will not work, but the chargers may.
It would be a 6 kW charging rate, which isn't too bad.
You have 220 L-L 3 phase? Wow, I've always heard Norway and Albania were the only countries to use that. Wonder how many more of us are out there. Do you have an N wire back to the transformer?
I see... So the problem is not the car but the EVSE. Anyway I can get a 220 V to 400 V transformer, but it'd be better to use what I already have.
Well... I have it because this is an old house and here in Spain it was usual still 30 years ago. Anyway I use L-L voltage at home (so my sockets have no neutral), but I do have a neutral coming from the street (3 ph + neutral) so it isn't IT but TT.
I think it's safer to have 220 V L-L at home because the voltage to earth of each wire is just 125 V. Anyway not a big issue as there are automatic protection switches in the main board...
Interesting. Then it must be the combination of IT and 230 V three phase that is unique to Norway and Albania. I didn't know anyone else used 230 V three phase.
Anyway, that you have an N wire to the house increases your chances of getting it to work, I think.
I agree, having neutral do increase my chances of charging without a transformer
This voltage is a legacy from the past, when 125 V L-N was the common voltage in the houses... Anyway from 30 or 40 years ago all the new buildings have 220 V L-N (now 230 V). Additionally, most users get single phase current only. Three phase is reserved for commerce or houses that have three phase motors (for irrigation or swimming pool, etc.), as mine.
Today is impossible to get 125/220 V, for new contracts 230/400 V is compulsory. I'm afraid I will be forced to upgrade soon...
Confirmation that the twin chargers deliver 22 kW (click the "charger" plus-sign): Tesla Charging en_EU | Tesla Motors
Yes, it was confirmed a few weeks ago. But as someone told here that the first cars were delivered without the twin chargers (with the promise to be retrofitted soon), but they were still able to recharge at 22 kW, that made me think about the possibility of get 22 kW on a single charger (and then 43 kW on the twins). That's why I asked someone who actually has an EU Model S and recharges at 22 kW, to check if there are one or two chargers under the back seat
Maybe... But then, why pay for the twin chargers if there's no benefit?? Just to charge at single phase and 80 amps, here in Europe??? It makes no sense for me.
As I said before, I am stubborn, and I still think that Tesla will "surprise" us
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