Transport Evolved

[mpt]

Check out TMC's Kevin Sharpe and I on this weeks Transport Evolved hosted by Nikki Gordon-Bloomfield (aminorjourney).

Kevin outlines his charity to bring charging stations to the UK and I have a rant about MPG.

[JRP3]

Not sure about the comment regarding 3 phase to get 240 volt. Almost all homes and businesses have 240V available.

[mpt]

Indeed, seems that each Chargepoint instal that I read about or use brings a 3-phase to deliver 208v@30A plus 110v@15A; not clear why though, why not just bring 240v@80A? Perhaps it's because businesses get 3-phase but homes don't?

[TEG]

Perhaps it's because businesses get 3-phase but homes don't?

Yes, that is basically the reason in the US.

Occasionally you do find a smaller business with 240V, but 208V from 3-phase seems more common at industrial locations.

Nominal supply voltage for these sites: 208V
http://www.evchargernews.com/regions/90240_1.htm Office Max / Home Depot Downey
http://www.evchargernews.com/regions/91007_1.htm LA Arboretum
http://www.evchargernews.com/regions/92691_1.htm Mission Hospital
http://www.evchargernews.com/regions/92802_3.htm Disneyland Hotel
http://www.evchargernews.com/regions/92821_1.htm Brea Downtown Parking
http://www.evchargernews.com/regions/92832_1.htm Costco Fullerton
http://www.evchargernews.com/regions/92821_2.htm Brea Civic Center
http://www.evchargernews.com/regions/93401_3.htm Marsh St Parking, San Luis Obispo
http://www.evchargernews.com/regions/94025_1.htm Sun Microsystems Usability Labs
http://www.evchargernews.com/regions/94133_1.htm Hyatt Fisherman's Wharf
http://www.evchargernews.com/regions/94534_1.htm Solano Community College
http://www.evchargernews.com/regions/95616_2.htm Davis, 4th and G Plaza (Tesla)
http://www.evchargernews.com/regions/95620_2.htm Pitt School Road at I-80 (Tesla)
http://www.evchargernews.com/regions/95621_1.htm Citrus Heights City Hall
http://www.evchargernews.com/regions/95678_5.htm Costco Roseville
http://www.evchargernews.com/regions/95690_1.htm Walnut Grove Library
http://www.evchargernews.com/regions/95814_19.htm Sacramento City Public Garage
http://www.evchargernews.com/regions/95837_2.htm Sacramento Airport - Daily B
http://www.evchargernews.com/regions/95837_12.htm Sacramento Airport - Terminal A
http://www.evchargernews.com/regions/96097_1.htm Comfort Inn Yreka (Tesla)

[mpt]

Yes, that is basically the reason in the US.

Good to know, thanks.

[Bud]

Hi, guys

[mpt]

Whoever came up with that confusing 3-phase system, and why?

It was a chap by the name of Nikola Tesla, you may have heard of him

He figured out that with the right layout these confounded generators & motors could be made much more efficient and easier to connect over long distances. Not everyone agreed at the time but it seems that he may have been right after all: http://en.wikipedia.org/wiki/Three-phase_electric_power

Thing is, he also predicted that we would be able to supply the entire world with power, wirelessly, from giant antennas... which seems mad... or it did...

[Bud]

Hi, guys

[JRP3]

You mean other than that the Roadster uses a 3 phase AC induction motor?

[mpt]

OK, but what does 3-phase have to do with a Tesla Roadster?

3-phase power is used in the roadster to drive the motor. Back to your original question; 3-phase is the native form of power that's delivered from the power stations to the grid. It's the standard used throughout the world, at different voltages and frequencies.

The roadster charges on single phase AC, stores it in the battery as DC and turns it into 3-phase to drive the motor.

You can obtain a single phase feed for the roadster from a 3-phase supply and, as that's more than likely found in business (per Teg) that's why we find ourselves charging from 3-phase.

At the end of the day, we need DC in the batteries of Mr. Tesla's namesake car yet it was he who pioneered 3-phase for generation. All the debate about which is best, 3-phase charging or DC charging is more about where you put the 3-phase to DC rectifier than any technical merit between the two electrical standards.