http://www.wired.co.uk/news/archive/2013-08/08/olev-buses-south-korea
just when we said that this would never work. Been tried with streetcars without success.
Yes...but how much electricity is lost between the bus and the road?
On streetcars, Washington DC had streetcars that received electricity from a buried trough, and I don't see why this wouldn't work with modern systems.
NW
NorthWestYes...but how much electricity is lost between the bus and the road?
Very little. This is not the old-fashioned induction system; it runs at much higher frequency and has better shaped-antenna coupling. Some of this gets around the old requirement for very close physical alignment of transmitter and receiver antennas in inductive charging arrangements.
With respect to the other thing: Conduit was a general disaster for a variety of reasons, most of which will suggest themselves to you if you think about what is involved in installing and maintaining such a system -- especially for high current at high voltage. There are several discussions of this, one quite recent, on RyPN. They are workable if there is no alternative, but just about any alternative is better...
Interesting. If there is little power loss, that opens whole new doors to vehicle transport... but since it is likely more costly than overhead wire, I think that that overhead system may be better except for on city streets (iirc, that was the reasoning for the DC conduit- not to spoil the city sightlines). And yes conduit is a disaster, I was suggesting more of a *smart* third rail embedded at street level, but that system must be flawless.
NorthWestI was suggesting more of a *smart* third rail embedded at street level, but that system must be flawless.
Interestingly enough, a better alternative of this design had been developed in the early years of the 20th Century, I believe by GE (I recently found a reasonably full description of the system in one of those Google Books digitizations of street-railway magazines, but cannot now locate it!).
This used intermittent stud contacts for the 'third rail' supply. These were only energized when the overrunning shoe on the car passed over them (there was a system of relays and detection current that accomplished this). Return current could be through the rails, or through a second line of studs, if dirt or electrolysis problems might tend to cause shorting. The portion of the studs above the pavement was not particularly larger than current Botts' Dots, and many of the advantages claimed for that style of lane marker might easily apply to streetcar lanes.
I might add that high-speed pickup for such a system is quite possible -- but that is another story!
The problem with the intermittent contacts energized only when necessary is that the system has to work perfectly or else. The "or else" would be either a stranded streetcar or a dead or stunned pedestrian.
Overmod NorthWestI was suggesting more of a *smart* third rail embedded at street level, but that system must be flawless. Interestingly enough, a better alternative of this design had been developed in the early years of the 20th Century, I believe by GE (I recently found a reasonably full description of the system in one of those Google Books digitizations of street-railway magazines, but cannot now locate it!). This used intermittent stud contacts for the 'third rail' supply. These were only energized when the overrunning shoe on the car passed over them (there was a system of relays and detection current that accomplished this). Return current could be through the rails, or through a second line of studs, if dirt or electrolysis problems might tend to cause shorting. The portion of the studs above the pavement was not particularly larger than current Botts' Dots, and many of the advantages claimed for that style of lane marker might easily apply to streetcar lanes. I might add that high-speed pickup for such a system is quite possible -- but that is another story!
Interesting, sounds like the power system that one of the German model train manufacturers (is it Marklin?) uses. In that system little metal posts/pins are embedded in the one piece track/roadbed and the locomotive power pickup depresses them as it travels over them. Pushing them down causes them to be energized thus transferring current to the loco..
"I Often Dream of Trains"-From the Album of the Same Name by Robyn Hitchcock
Yes, that is the Märklin System.
I suppose the bus driver knows he's in a charge zone if he looks in the rear-view mirror and sees the passengers' hair standing on end.
NorthWestOn streetcars, Washington DC had streetcars that received electricity from a buried trough, and I don't see why this wouldn't work with modern systems.
Well, just ask the people who ran them.
They were not as simple as they looked. There was a sled of some sort inside of the slot that made actual contact with the conductors, the car would attach itself to the sled through the slot. IIRC there was a guy down in a pit to apply and remove these sleds as a car entered and left conduit territory.. Snow, Rain and Ice were other issues.
Some modern street cars are diesel powered as in NJT's River Line.
LION would think of battery power in mid-town and either a gen-set or a trolley wire (or both) to recharge the batteries.
ROAR
The Route of the Broadway Lion The Largest Subway Layout in North Dakota.
Here there be cats. LIONS with CAMERAS
Overmod NorthWestYes...but how much electricity is lost between the bus and the road? Very little. This is not the old-fashioned induction system; it runs at much higher frequency and has better shaped-antenna coupling. Some of this gets around the old requirement for very close physical alignment of transmitter and receiver antennas in inductive charging arrangements.
The fundemental equation for coupled resonators is that the critical coupling coefficient "k" is the inverse of the geometric mean of the quality factors "Q" for the two resonators.
kcrit = 1/(Q1 x Q2)
If the Q's of both of the induction coils are 100, the coupling coefficient can drop down to near 1% (k=0.01) and still get reasonable power transfer. The tricky part is keeping both coils on the same resonant frequency.
- Erik
The buses in Korea have battery's and the lanes are low powered recharge lanes such saying
erikemkcrit = 1/(Q1 x Q2)
Erik,
If my toothbrush can work with a renaissance frequency how come we can't do the same thing with buses? Are buses all that different from toothbrushes? Or other induction motors?
John
John,
I can think of three differences.
One is that it is easier to get good coupling between a toothbrush and the wireless charger than it is between a bus and the loop below.
Second is that a loop in the ground will likely have a lower Q than the loop in the toothbrush charger due to induced ground losses - unless you want to go to the expense of making a copper or aluminum lined cavity under the stationary coupling coil.
Third is that inefficiency is less of an issue when you're talking about a watt or less for recharging the toothbrush versus the order of 100 kW or more to recharge the bus.
erikemI can think of three differences.
Gee whiz, Erik, you sure are a disappointing guy. With your knowledge I was sure you could show how there is really no difference between a toothbrush and a bus. What a revoltin' development this is.
"Three differences" refers specifically for wireless charging - a bus would be an awkward thing to brush my teeth with and while I've read & heard stories about witches riding brooms, there is a distinct lack of any material about using a toothbrush as a mode of transportation...
erikem while I've read & heard stories about witches riding brooms, there is a distinct lack of any material about using a toothbrush as a mode of transportation...
You think you're so smart, Erik, but I'll show you. I'll get some wheels for my toothbrush and ride it down town to Newark Penn Station. Then we'll see who's laughing. You better get ready to be embarrassed, Erik, because before I'm done with you the whole world will know how foolish you really are.
If it's a toothbrush for a sperm whale, I might believe you.
P.S. I remember reading about overhead contacts at bus stops for spinning up an onboard flywheel - ISTR it was in a mid-1960's issue of Popular Science.
erikemP.S. I remember reading about overhead contacts at bus stops for spinning up an onboard flywheel - ISTR it was in a mid-1960's issue of Popular Science.
I recall reading about that in the 1950's in my father's Popular Mechanics. But they could well have been still writing about it in the 1960's.
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