EV Digest 4583
Topics covered in this issue include:
1) Re: Thoughts on friction and traction
by Rush <[EMAIL PROTECTED]>
2) Deka Dominators to a good home
by Tom Hudson <[EMAIL PROTECTED]>
3) Re: Thoughts on friction and traction
by Danny Miller <[EMAIL PROTECTED]>
4) Re: Thoughts on friction and traction - rotating mass
by "Philip Marino" <[EMAIL PROTECTED]>
5) Re: e-meter and DC/DC - another possible part
by Victor Tikhonov <[EMAIL PROTECTED]>
6) Orange Vu-Tron cable
by TiM M <[EMAIL PROTECTED]>
7) Re: LA Times front page article on EVs today
by Neon John <[EMAIL PROTECTED]>
8) RE: No Transmission
by "Pestka, Dennis J" <[EMAIL PROTECTED]>
9) Time for new batteries soon
by [EMAIL PROTECTED]
10) Re: LA Times front page article on EVs today
by ROBERT RICE <[EMAIL PROTECTED]>
11) Re: Opportunity power
by "David Roden" <[EMAIL PROTECTED]>
12) Re: Correct AGM charging (was: A timer on PFC chargers)
by russco <[EMAIL PROTECTED]>
13) RE: Thoughts on friction and traction
by "Roger Stockton" <[EMAIL PROTECTED]>
14) Re: EV utility power leveling. Re: Fwd: Opportunity power
by Evan Tuer <[EMAIL PROTECTED]>
15) RE: Orange Vu-Tron cable
by "Brown, Jay" <[EMAIL PROTECTED]>
16) Re: Correct AGM charging (was: A timer on PFC chargers)
by Ryan Stotts <[EMAIL PROTECTED]>
17) RE: LA Times front page article on EVs today
by "Chris Tromley" <[EMAIL PROTECTED]>
18) Re: Opportunity power
by Neon John <[EMAIL PROTECTED]>
19) Re: Powering refridgerator off of HV traction pack
by ROBERT RICE <[EMAIL PROTECTED]>
20) RE: LA Times front page article on EVs today
by "David Roden" <[EMAIL PROTECTED]>
21) Re: Powering refridgerator off of HV traction pack
by "Michaela Merz" <[EMAIL PROTECTED]>
22) Re: 200VDC to 120VAC Inverter
by Edward Ang <[EMAIL PROTECTED]>
23) Re: EAA, was Re: LA Times front page article on EVs today
by "Michaela Merz" <[EMAIL PROTECTED]>
24) Re: 200VDC to 120VAC Inverter
by Danny Miller <[EMAIL PROTECTED]>
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Is it that when the car accelerates there is more force applied which deforms
the tires thereby increasing the surface area so therefore more friction is
applied?
Also the same with the wings on the back that apply more downward force as the
speed increases, the tire surface increases, as does the friction/traction?
Just my .04 kW
Rush
Tucson AZ
www.ironandwood.org
----- Original Message -----
From: "Peter VanDerWal" <[EMAIL PROTECTED]>
To: " Electric Vehicle Discussion List" <ev@listproc.sjsu.edu>
Sent: Tuesday, August 16, 2005 6:35 AM
Subject: Thoughts on friction and traction
>I just came across an interesting web article:
> http://www.physlink.com/Education/AskExperts/ae140.cfm
>
> Basically it states that contact patch size has no effect of friction, and
> presumably traction.
>
> This would imply that:
> A) the number of tires on a vehicle has no effect on traction, and
> B) the width of tires does not improve traction.
>
> This, to my mind, begs the question...why do race cars have wide tires?
>
> Any ideas?
>
>
>
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--- Begin Message ---
I have 24, Group 24, 8G24NH (No Handle) Deka Dominators available free
for anyone who wants them and will come get them. These served in my
Solectria E-10 pickup for the last five years and while their capacity
is down somewhat, they are in really good shape (no bulging, good
voltages, etc.). From day 1 these were operated with PowerCheq voltage
balancers to keep the pack in balance and it shows. These might be good
batteries for someone testing a vehicle or even for someone wanting a
big honking battery backup bank. I'm replacing them because my truck's
range has dropped -- I would guess you can get ~20Ah out of them at
ordinary EV driving currents.
If nobody wants 'em, they'll just get hauled to my local battery shop
for recycling, which would be kind of a waste.
I'm just North of Milwaukee WI. Please contact me off list if you want
them.
-Tom
--
Thomas Hudson
http://portdistrict5.org -- 5th District Aldermanic Website
http://portev.org -- Electric Vehicles, Solar Power & More
http://portgardenclub.org -- Port Washington Garden Club
http://portlightstation.org -- Light Station Restoration
http://klanky.com -- Animation Projects
--- End Message ---
--- Begin Message ---
By the friction theory, more surface area does not increase the friction
force because the same normal force is spread out over a larger area.
Thus the contact area is irrelevant and it only comes down to the
coefficient of friction between the two surfaces and the applied weight.
Of course in the real world there are many other factors. A thin solid
tire can only take so much force before the rubber is crushed. An air
filled tire will bulge and deform until the inner rim strikes the
ground. Deformation is an efficiency issue since it burns up energy as
it rolls around the outside of the circle. I don't really know why
racing slicks are the best choice, but don't doubt they are. I assume
cooling is quite an issue, as is just having a substantial area for
ablation. Those tires are fairly soft to get a better coefficient of
friction, but very prone to shedding rubber on the asphalt, right?
Danny
Rush wrote:
Is it that when the car accelerates there is more force applied which deforms
the tires thereby increasing the surface area so therefore more friction is
applied?
Also the same with the wings on the back that apply more downward force as the
speed increases, the tire surface increases, as does the friction/traction?
Just my .04 kW
Rush
Tucson AZ
www.ironandwood.org
--- End Message ---
--- Begin Message ---
From: David Dymaxion <[EMAIL PROTECTED]>
Reply-To: ev@listproc.sjsu.edu
To: ev@listproc.sjsu.edu
Subject: Re: Thoughts on friction and traction
Date: Tue, 16 Aug 2005 10:39:11 -0700 (PDT)
Something I read:
Wider tires cover a wider swath, and are statistically more likely to
be on a patch of pavement with good traction.
Another thought, taller tires increase the moment of inertia more,
making the car accelerate more slowly, which is another motive for a
shorter but wider tire.
Not necessarily. The inertia of a taller tire may be higher, but the
equivalent "extra" straightline mass of a taller tire/wheel due to that
inertia may be lower.
Here's why: The equivalent additional mass equals the moment of inertia
of the tire/wheel divided by the square of the rolling radius. So, because
the rolling radius is larger on taller tires, the equivalent extra mass may
be lower than for shorter tires. This makes sense when you consider that a
larger rolling radius tire turns more slowly at a given vehicle speed. ( And
accelerates slower, rotationally, than a smaller radius tire)
In general, I think too much emphasis is given to rotating tire/wheel mass.
One of these days, I'll measure the actual inertia of a tire/wheel ( easy to
do with a bifilar pendulum) and figure the additional mass due to its
inertia. My guess is that it is usually about 1/4 to 1/3 of the actual
tire/wheel mass.
If that's true, then removing a pound of tire/wheel rotating mass would be
the equivalent of removing 1 1/4 to 1 1/3 pounds of vehicle mass. Nowhere
near two or even seven times the mass, as I have sometimes read.
AND, that "extra mass" effect is only while accelerating - there is no
penalty for rotating mass when hill climbing, or, any increase in rolling
resistance or other sources of vehicle drag.
Phil
_________________________________________________________________
FREE pop-up blocking with the new MSN Toolbar get it now!
http://toolbar.msn.click-url.com/go/onm00200415ave/direct/01/
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--- Begin Message ---
It is isolated.
Victor
Danny Miller wrote:
Might be. The spec sheet doesn't mention being isolated in its
features. However, there is no purpose that I can see in making an
unregulated 12v-12v converter other than isolation. There are separate
"-" pins for Vin and Vout, though in some cases this is used as a
pseudoground. However it lists 500v "isolation" in the specs. They
don't mention what it's isolating but I'm reading it as input-to-output.
Danny
Nick Viera wrote:
Ryan Bohm wrote:
For my e-meter isolation, I used Mouser part number 580-HL02U12S12Y
<http://www.mouser.com/index.cfm?handler=displayproduct&lstdispproductid=333042>.
It has worked well, and was only $8.88.
Where does it say that this DC/DC converter is isolated? Looking at
the data sheet and Mouser catalog pages seem to indicate that part
number 580-HL02U12S12Y is not an isolated converter!
--
Victor
'91 ACRX - something different
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--- Begin Message ---
McMaster car carries it and will ship anywhere. The
link is:
http://www.mcmaster.com/ctlg/DisplCtlgPage.asp?ReqTyp=CATALOG&CtlgPgNbr=3142&CtlgEdition=&RelatedCtlgPgs=3142,726&sesnextrep=504042087108969&ScreenWidth=1920&McMMainWidth=1713
If that doesn't work, go to mcmaster.com and enter
vu-tron in the find box. Make sure you put the dash
in. 2/0 goes for $3.23 a foot, plus shipping.
TiM
____________________________________________________
Start your day with Yahoo! - make it your home page
http://www.yahoo.com/r/hs
--- End Message ---
--- Begin Message ---
On Tue, 16 Aug 2005 10:00:22 -0700, "Lawrence Rhodes"
<[EMAIL PROTECTED]> wrote:
>Copy and paste into your browser: or click on if you are feeling lucky.
>http://www.latimes.com/news/local/la-me-ev15aug15,0,5131192.story?coll=la-home-headlines
Damn, I hate that kind of article. It perpetuates the myth that all
EV drivers are eco-fruitcakes. It un-does all the work us un-True
Believers do to disassociate EVs and ourselves from the fruitcakes.
I'm still waiting, in vane, it appears, for an article that shows
Joe-everybodies driving EVs because they're fun and because they're
cheap and convenient to operate.
---
John De Armond
See my website for my current email address
http://www.johngsbbq.com
Cleveland, Occupied TN
--- End Message ---
--- Begin Message ---
Ryan;
I calculate 63 mph at 4000 rpm with 26" diameter tires and a 4.875 rear end.
Thanks;
Dennis
-----Original Message-----
From: Ryan Stotts [mailto:[EMAIL PROTECTED]
Sent: Tuesday, August 16, 2005 1:45 PM
To: ev@listproc.sjsu.edu
Subject: Re: No Transmission
Pestka, Dennis J wrote:
> Can someone explain the problems with eliminating the transmission and
> with setting up a direct drive?
The appeal of not having a transmission is nice. 1 less part, less drive
line losses.
Without it, what's your top speed going to be? Also, the motor is going to
be spinning at full tilt at that speed. Is it going to be using the least
amount of power at that motor rpm?
With a transmission, any speed at nearly any rpm can be had..
Does the White Zombie have more range then Blue Meanie?
What's it like driving down the street at a good clip(~60 mph?) in White
Zombie?
--- End Message ---
--- Begin Message ---
It's getting near time for a new set of batteries in my Tropica. I've gotten
about 6k miles and 18 months out of these, much better than last time. The
charger isn't terminating normally any longer as the current won't drop at the
set voltage. It's not adjustable. This pack has aways been wimpy however. It
never got the range of the previous pack. I'm using US225s. At speed on the
freeway I'm pulling about 160 amps (72v pack) and I do drive on the freeway
about 26 miles 5 days a week. Is this about the life I can expect from these
batteries? Is there any logic to going to to Optimas or something that can
handle the higher currents better? My previous pack had range of about 35 miles
on a warm day of all freeway miles.
thanks,
Steve
--- End Message ---
--- Begin Message ---
Neon John <[EMAIL PROTECTED]> wrote:
On Tue, 16 Aug 2005 10:00:22 -0700, "Lawrence Rhodes"
wrote:
>Copy and paste into your browser: or click on if you are feeling lucky.
>http://www.latimes.com/news/local/la-me-ev15aug15,0,5131192.story?coll=la-home-headlines
Damn, I hate that kind of article. It perpetuates the myth that all
EV drivers are eco-fruitcakes. It un-does all the work us un-True
Believers do to disassociate EVs and ourselves from the fruitcakes.
I'm still waiting, in vane, it appears, for an article that shows
Joe-everybodies driving EVs because they're fun and because they're
cheap and convenient to operate.
Hi All;
Hell, ANY publicity for EV's is a good start. What it tells Joe Sixpack,
when he gets home from work, (IF he still has a job) after spending, say 50 bux
to fill up his SUV, or pickup, that there IS an alternative to Big Oil. Now Joe
didn't tow the camper an' kids up to Yellowstone this year because he can't
afford the gas, just getting around town is eating his wallet or credit card
alive!
As for the Joe EVerybodys? Stand up an take a bow! It's US! We have to carry
the flag here. By driving and show and telling whatEVer we have. After all, I
havent bought a muffler system, or tuneup or glow plugs or injecters, or oily
oil changes for my Rabbit in YEARS!
---Seeya at Woodburn
Bob
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--- Begin Message ---
About 10 years ago I took part in the "peak performers" scheme in
southwestern Indiana. The local utility, SIGECO, gave me a discount on my
electric bill in return for letting them shut down my electric water heater
and air-con unit for a few minutes at a time, using a radio controlled
gadget. I never noticed any discomfort from the scheme; indeed I never
even noticed when they were using it. It seemed to work quite well. I'd be
glad to participate again, if it were offered here.
Similarly, I think a peak-managing v2g strategy with EVs would be welcome
(that is, assuming they could find enough EVs connected to the grid at peak
periods ;-). If they paid me (or discounted my electric bill) a reasonable
amount to cover the potential depreciation of my EV battery from cycling,
which could be managed to be only a few percent anyway, and for any modest
inconvenience, I'd certainly be willing to participate.
They could cover the costs of paying the participants, and of the hardware
required, by adding a peak-usage surcharge to others' bills. Call me naive
if you will, but I rather like the idea of having people pay a little more
for extra convenience. I especially like having them pay extra for
behaviour that has a negative impact on others' lives. It's a private-
enterprise equivalent to the social benefit taxation and incentive schemes
applied in many European nations.
David Roden - Akron, Ohio, USA
EV List Assistant Administrator
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--- End Message ---
--- Begin Message ---
Joe Smalley wrote:
2) The 2 amp finishing current (step 3 of the IUI profile) is normally
provided by a charger programmed to provide this. The PFC chargers only
provide a IU profile and the 2 amp finishing current must be manually set
and monitored.
Gee, the Russco Three Stage Chargers are designed for proper Optima
charging. The line of Russco 3S chargers provides first stage
adjustable constant current, second stage adjustable constant voltage,
and third stage adjustable constant current over an adjustable duration.
The final timed duration latches to prevent disastrous over charging.
All this with PFC and GFI protection. And Battery Regulator Disconnect
for the third stage. Small size and hundreds under $1K, too.
Availability since 1997.
Russ Ksufmann
RUSSCO Engineering
The other PFC Charger With GFCI
--- End Message ---
--- Begin Message ---
Danny Miller [mailto:[EMAIL PROTECTED] wrote:
> By the friction theory, more surface area does not increase
> the friction force because the same normal force is spread
> out over a larger area. Thus the contact area is irrelevant
> and it only comes down to the oefficient of friction between
> the two surfaces and the applied weight.
This is exactly correct.
As Paul Compton pointed out, however, it is *grip*, not *friction* that
is of interest with respect to tires.
Although the frictional force does not increase with a wider tire, the
grip does because grip depends not only on the frictional force but on
the fact that the tire tread deforms over irregularities in the road
surface and "interlocks" with it to provide greater traction than
friction alone. This is where the really soft compound tires get a
bunch of their grip from.
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
On 8/16/05, Neon John <[EMAIL PROTECTED]> wrote:
> Not only will they want to charge the battery immediately upon
> arriving home, they'll want it charged fast. Nobody wants to wait,
> even if speed isn't necessary. Look at the progression of NiMH
> consumer batteries and chargers. Is there anyone (OK, is there anyone
> else?) who'll still wait overnight for batteries to recharge? Not me.
> My new 15 minute charger tends to seem slow on occasion.
I've always charged my cars from midnight onwards, to take advantage
of half price electricity. Market forces at work.
The possibility that you might need the uncharged car in an emergency
is fair enough, but it's hardly newsworthy. If you got home with the
gas tank on empty intending to fill it on your morning commute, it's
the same situation if you suddently need to drive to hospital or
something.
--
EVan
http://www.tuer.co.uk/evs2
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--- Begin Message ---
If you don't have to have Orange then here is the cheapest place I have
found.
http://www.weldingsupply.com/cgi-bin/einstein.pl?Next::1:UNDEF:OR:terms:
:PA#A2
304-1330 2/0 Weld Cable Black Info. $1.56 1/FT
304-1330Y 2/0 Weld Cable Yellow Info. $1.57 1/FT
304-1330B 2/0 Weld Cable Blue Info. $1.57 1/FT
304-1330G 2/0 Weld Cable Green Info. $1.57 1/FT
304-1337 2/0 Weld Cable Red Info. $1.57 1/FT
---------------------------------------------------------------------
Jay Brown
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of TiM M
Sent: Tuesday, August 16, 2005 2:58 PM
To: EV-List-Post
Subject: Orange Vu-Tron cable
McMaster car carries it and will ship anywhere. The
link is:
http://www.mcmaster.com/ctlg/DisplCtlgPage.asp?ReqTyp=CATALOG&CtlgPgNbr=
3142&CtlgEdition=&RelatedCtlgPgs=3142,726&sesnextrep=504042087108969&Scr
eenWidth=1920&McMMainWidth=1713
If that doesn't work, go to mcmaster.com and enter
vu-tron in the find box. Make sure you put the dash
in. 2/0 goes for $3.23 a foot, plus shipping.
TiM
____________________________________________________
Start your day with Yahoo! - make it your home page
http://www.yahoo.com/r/hs
--- End Message ---
--- Begin Message ---
russco wrote:
> All this with PFC and GFI protection. And Battery Regulator Disconnect
> for the third stage. Small size and hundreds under $1K, too.
>
> Availability since 1997.
I was searching for more info on these chargers. What's the main website?
http://www.madkatz.com/russco.html
--- End Message ---
--- Begin Message ---
Michaela Merz wrote:
> If the EAA what not sleep that soundly, we would read more about ev's, we
> would see more charging stations, might have better batteries and we would
> not be treated like weird circus animals.
>
> I have never seen any club or association that does such little in regard
> to public relations, public opinion forming and lobbying as the EAA. They
> haven't even changed the website for quite some time.
>
> I have to ask myself why I am spending money on a membership.
>
> No wonder everybody believes EV'ers are nerds with an attitude.
Hi Michaela,
As others have pointed out, the EAA is run by volunteers. Many of them put
in looooong hours, and I'm sure at times they wonder why. No one has the
time to do this work, so the ones who step up get worn out. I for one
really appreciate their efforts.
<armchair quarterback mode on>
Having said all that, I wonder how the national EAA funds are dispersed.
There are many local chapters which receive some of that money, but you're
right - on a national level no one ever hears about the EAA.
I do know that the tax status of EAA means they are not legally allowed to
directly lobby legislators. They are an educational organization. But
y'know, you'd think more news reports would quote EAA officers, more EV
notables would be interviewed, more EV-related stories would hit the news
with a pro-EV spin.
We EVers tend to be tech-types and/or tree-huggers. We're typically a very
independent lot. What we *really need* is someone with PR smarts. The
technology is there. The PR is not.
<mode off>
Making converts one at a time does work. But man, does it take some time to
make any progress that way.
Chris
P.S. Just thinking out loud here, but I wonder if PR firms do public
service work? They get a tax break, we get some exposure. Aren't magazines
and TV stations required to do a certain amount of public service work?
Hasn't Smokey the Bear received more than his share of coverage? Let's see
some public service announcements showing how air quality is improved by
EVs.
--- End Message ---
--- Begin Message ---
On Tue, 16 Aug 2005 16:16:59 -0400, "David Roden" <[EMAIL PROTECTED]>
wrote:
>About 10 years ago I took part in the "peak performers" scheme in
>southwestern Indiana. The local utility, SIGECO, gave me a discount on my
>electric bill in return for letting them shut down my electric water heater
>and air-con unit for a few minutes at a time, using a radio controlled
>gadget. I never noticed any discomfort from the scheme; indeed I never
>even noticed when they were using it. It seemed to work quite well. I'd be
>glad to participate again, if it were offered here.
The water heater controller is fairly painless, at least until it
fails. Very little to be gained there, however, particularly now with
the prevalence of low loss heaters vs back then.
AC is a whole 'nuther matter. For folks who aren't at home during the
day, a setback thermostat is much cheaper and MUCH more reliable. For
those who ARE at home during the day, turning off the AC in the heat
of the day just doesn't cut it. Folks who work to have a nice house
or apartment just aren't going to tolerate being uncomfortable and no
rational person is going to expect them to. Same reason those "set
your thermostat to 78deg" campaigns are so silly and ineffectual.
>Similarly, I think a peak-managing v2g strategy with EVs would be welcome
>(that is, assuming they could find enough EVs connected to the grid at peak
>periods ;-). If they paid me (or discounted my electric bill) a reasonable
>amount to cover the potential depreciation of my EV battery from cycling,
>which could be managed to be only a few percent anyway, and for any modest
>inconvenience, I'd certainly be willing to participate.
I can matchbook this analysis and see that it makes no sense. Sit
down and so some simple math, assuming a typical pack cost, life and
an estimated number of cycles per year.
As a ratepayer and stockholder, I'd have a fit if any utility ever
proposed to waste money that way on inefficient and unreliable power
storage compared to other more centralized techniques. Especially
when the real solution is to build more generating and transmission
capacity in the first place.
>
>They could cover the costs of paying the participants, and of the hardware
>required, by adding a peak-usage surcharge to others' bills. Call me naive
>if you will, but I rather like the idea of having people pay a little more
>for extra convenience. I especially like having them pay extra for
>behaviour that has a negative impact on others' lives. It's a private-
>enterprise equivalent to the social benefit taxation and incentive schemes
>applied in many European nations.
Typical leftist approach of using the government to force your beliefs
on everyone. Not any different than the fundies who want to use the
government to force their brand of religion on everyone.
What if all us armchair quarterbacks in government and out, just
stepped back and let the folks who know what they're doing generate
the electricity we need? After all, that worked pretty damned well
before the obstructionists gained sway.
In places where the obstructionists aren't allowed to do much more
than create noise, such as here in the Tennessee Valley, things still
pretty much work that way. TVA does a pretty good job of supplying us
good cheap power that is as reliable as the dawn. They'd be doing a
LOT better had they not had to suffer the Carter/Freeman axis of
destruction and the follow-on Reagan do-nothing years.
John
---
John De Armond
See my website for my current email address
http://www.johngsbbq.com
Cleveland, Occupied TN
--- End Message ---
--- Begin Message ---
Bob Bath <[EMAIL PROTECTED]> wrote:
I was in So. Cal. not long ago, and they had localized
outages. It got me thinking: What is to keep someone
from disconnecting the Anderson connector of their EV;
hooking it to a high voltage inverter, and powering
the fridge and a couple of lights in this situation?
Anyone else have this up and working as a backup
power source?
Hi Bob;
Nice thought. Heres a market for a higher voltage inverter, say, 120 volts to
120 volts. Yeah, a rather limited market for now, but wouldn't it be nice to be
able to buy an inverter that you could dial or bussbar up your IMPUT
voltage?Electronic Geeks an' Garus?
Right now we hafta do with the Chinesy Coleman 4000 watt units from Harbor
Fright, for now. You WILL be unbalancing your pack tapping into 12 volts worth
of it, at a time.Old rotery converters would be a nice find. I wish I had
swiped all the old Car lighting ones off the old New Haven passenger cars when
they, ConRail, junked them, sigh!
Seeya at Wouldburn.
Bob
_
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--- Begin Message ---
On 16 Aug 2005 at 16:55, Chris Tromley wrote:
> P.S. Just thinking out loud here, but I wonder if PR firms do public
> service work?
Ad agencies like to win awards, because it makes them look good, which
brings in more business. Trouble is, the clever, entertaining campaigns
that win awards often don't do such a good job of selling the client's goods
or services. So how do you create a campaign to win an award? One way is
to contract with a nonprofit organization to do their campaign cheaply or
even pro bono. The nonprofit gets a free or cheap campaign (usually worth
what they paid ;-), and the agency gets a contest entry. Win-win, sort of.
> They get a tax break, we get some exposure.
No tax break that I know of. I'm amenable to correction on that.
> Aren't magazines
> and TV stations required to do a certain amount of public service work?
I can't speak for magazines, but I doubt it.
I can tell you for sure that broadcasters haven't been required to air
public service announcements since the Reagan Administration's first round
of broadcast deregulation. A few still do as community service, but I could
probably count the number on my hands.
Surprisingly, even public radio and television stations are not required to
air PSAs. Most do not, because as a result of stagnant public funding, they
fill up their break time with paid "funding credits" (commercials).
However, many public broadcasters offer reduced-cost paid announcements for
nonprofit organizations. If you have a budget, these are worth asking
about.
I'm sorry to say that it's a complete waste of time, money, and paper to
send PSA scripts "on spec" to radio and television stations. They just go
straight into the recycling bin - or the trash can. A dismaying number of
nonprofits don't seem to realize that, however. If they would listen to /
watch the stations they're deluging with "news releases" and PSAs, they
might realize that their efforts were mostly futile.
What ^does^ work is to get the attention of their news departments. It's
not easy, but sometimes you can find an interesting angle and pitch it
successfully to the news director. With a little creativity, you can
sometimes get a short piece on the news. This works for both commercial and
non-commercial broadcasters, television and radio. But note that sending a
paper news release is largely ineffective. Pick up the phone. Sometimes an
email will work, too.
David Roden - Akron, Ohio, USA
EV List Assistant Administrator
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--- End Message ---
--- Begin Message ---
> Hi Bob;
>
> Nice thought. Heres a market for a higher voltage inverter, say, 120
> volts to 120 volts. Yeah, a rather limited market for now, but wouldn't
> it be nice to be able to buy an inverter that you could dial or bussbar
> up your IMPUT voltage?Electronic Geeks an' Garus?
Like I said: Exeltech is selling a DC/AC converter (I just bought one)
that takes High Voltage DC from the battery pack (108 to 140 VDC input)
Regards,
Michaela
--- End Message ---
--- Begin Message ---
After toying around with different configurations of a
transformer, I found some interesting stuff. But, I
still could not quite get the physics behind it.
Could we use a transformer as an AC voltage divider?
Look at the 2 configurations below.
___________________
| 240-36V
-+__ __________ AC
*) || C*
) || C
240V ) || C 36V
AC ) || C AC
--+_) || C___
| |
|_________|
This is the "normal" way to reduce the AC voltage as
in an auto-transformer.
But, how about this? I am essentially using the
transformer as a voltage divider. I tested this
configuration, and it seems to divide the voltage
happily. But, how does it respond to different loads?
_______________________
| 240-36V
| ___________________ AC
| |
--(---+__ ________
| *) || C |
| ) || C |
|___ ) || C 36V |
| ) || C AC |
240V |_) || C*__ |
AC | | |
|_________| |
|
______________________|
My brain needs some time to digest this.
Ed Ang
--- Lee Hart <[EMAIL PROTECTED]> wrote:
> Lee Hart wrote:
> >> Yes, that can work. You might not need a
> transformer, either.
> >> The actual pulse width can be set to determine
> the AC voltage
> >> generated.
>
> Edward Ang wrote:
> > Wouldn't this only give you the RMS of the voltage
> generated,
> > but the actual peak voltage would be a lot
> different? This would
> > be very bad if you connect something with an input
> cap rated at
> > 200V (for 110Vac) because your Vdc (or peak) might
> be above 200V.
>
> I'm talking about a simple inverter that just chops
> the DC into a square
> wave, and uses phase control on the AC to limit the
> RMS voltage to what
> the load needs. For this to work, everything depends
> on what you are
> going to power with that inverter's AC.
>
> Power supplies for electronic equipment rectify the
> AC line, and mainly
> care about the *peak* voltage. Phase control on a
> square wave inverter
> is not effective with such loads. You should not
> power such devices from
> an inverter that just controls pulse width.
>
> Light bulbs, heaters, motors, transformers, and
> other simple loads care
> about the RMS value of the voltage, not the peak. So
> you *can* power
> such loads with a simple inverter that just controls
> pulse width. For
> example, 240vdc can be inverted into a 240vac square
> wave, and then
> phase controlled to become a 0v/+240v/0v/-240v
> "modified sine wave". If
> the total on-time is 25%, the RMS voltage is 120v,
> and will power a 120v
> light bulb or heater exactly the same as if it were
> on 120vac. At 60hz,
> this means:
>
> 0v from 0 - 6.25 msec
> 240v from 6.25 - 8.33 msec
> 0v from 8.33 - 14.58 msec
> 240v from 14.58 - 16.67 msec
>
> An inductive load like a motor or transformer will
> require a slightly
> different ratio. The exact ratio depends on how
> heavily loaded it is; a
> light load it is mainly inductive and is more
> towards 50% on-time.
> Heavily loaded it moves toward a resistive load and
> 25% on-time.
>
> Yes, the actual voltage applied to the device is
> much higher. But
> essentially all motors and transformers have enough
> insulation to pass
> UL hipot testing, which requires 1250 vac or more.
>
> > Actually, my goal is to get high power AC from my
> '04
> > Prius. I have alrealy tapped into the 201.6V pack
> > with a pair of 10 gauge wires. The test data on
> this
> > site (www.priups.com) shows that the voltage would
> > vary between about 210-230V if the battery is down
> to
> > 2 bars and the ICE kicks in to recharge it to 3
> bars.
> > If scaled properly, this voltage range would
> produce
> > 110-120Vac or 220-240Vac without any adjustment.
> This
> > is very tempting. (An EV would have a higher
> ranges
> > of voltage swing that might need a variac if set
> up
> > this way.) The idea of having an AT-PZEV 10kW
> backup
> > generator in the garage is pretty exciting.
>
> If you want to power any arbitrary load that you
> might plug in, then you
> need a "proper" inverter that delivers something
> closer to a sine wave.
> To make *any* load work, you will need a true
> sinewave inverter.
> --
> "One doesn't discover new lands without consenting
> to lose sight of the
> shore for a very long time." -- Andre Gide
> --
> Lee A. Hart, 814 8th Ave N, Sartell MN 56377,
> leeahart_at_earthlink.net
>
>
____________________________________________________
Start your day with Yahoo! - make it your home page
http://www.yahoo.com/r/hs
--- End Message ---
--- Begin Message ---
Lawrence (and others):
I have worked for some associations and co-ops. And it doesn't matter
if someone works for free. The job has to be done. And this is just an
example: Changing the 'news' section of the website at least once a week
is a 20 Minutes job. Don't have time to do it? Find somebody. Or step
aside and let somebody else take responsibility.
And no, I am not re-trying to send emails to different EAA chapters
without getting _any_ response at all.
In order for the EV community to change, we have to come up with some
solutions. The industry is most certainly not going to help us a lot. It
would be EAA's job to start something like a co-op in order to get us the
batteries we want. We could get advanced batteries if we wouldn't ask for
4,7 or ten batteries at a time. It is a whole different game if we buy 100
or so. But we would have to stick together, build the chargers we need,
build the buying power and then talk to those Safts, Valences and
Thundersky people.
I approached the EV community with great enthusiasm and the believe that
battery powered vehicles are one solution for a lot of problems. But I
found out, that there has been no change or advances within the last 3 or
4 years.
Why don't we, as a community, build the vehicle we should show the press.
If everybody would contribute money or know-how or time, we would be able
to show the American public that there are working alternatives.
I am just a bit frustrated. Because the technology to change things would
be available. But as a single individuum, it is almost impossible to
either get the right technology (for a reasonable amount of money) or get
the attention the ev-environment deserves.
.. now awaiting the firing squad .. :)
--- End Message ---
--- Begin Message ---
I'm not sure I follow your schematic here, but the second just looks
like a common usage of a transformer.
There are several things to keep in mind here. One, you'd need to build
an inverter anyways to drive the transformer from a 200v+ battery pack.
Second, a transformer capable of carrying a significant number of
voltamps at 50/60Hz is huge. Usually we use high freq- 20KHz-100KHz- to
make better use of specially designed high freq cores. But then you'd
need to rectify it out and build yet another inverter to make 60Hz
120v. Third is you've got to accomodate changes in pack voltage.
That is, I'm still assuming you want 120v AC from a HV EV pack.
I kinda like the idea of straight out gutting a power inverter so the
12v-to-HV rails stage is gone. Then we build a DC/DC converter to
adjust the input voltage to something the rails can take, and regulated
too. Actually this isn't that hard and doesn't require a lot of
inductance as long as the gap between battery voltage and desired HV
rail voltage is not great. The trick is fooling the enable lines
between the stages and this may be a nonissue or it could make it
unfeasible. Depends on model.
Danny
Edward Ang wrote:
After toying around with different configurations of a
transformer, I found some interesting stuff. But, I
still could not quite get the physics behind it.
Could we use a transformer as an AC voltage divider?
Look at the 2 configurations below.
___________________
| 240-36V
-+__ __________ AC
*) || C*
) || C
240V ) || C 36V
AC ) || C AC
--+_) || C___
| |
|_________|
This is the "normal" way to reduce the AC voltage as
in an auto-transformer.
But, how about this? I am essentially using the
transformer as a voltage divider. I tested this
configuration, and it seems to divide the voltage
happily. But, how does it respond to different loads?
_______________________
| 240-36V
| ___________________ AC
| |
--(---+__ ________
| *) || C |
| ) || C |
|___ ) || C 36V |
| ) || C AC |
240V |_) || C*__ |
AC | | |
|_________| |
|
______________________|
My brain needs some time to digest this.
Ed Ang
--- Lee Hart <[EMAIL PROTECTED]> wrote:
Lee Hart wrote:
Yes, that can work. You might not need a
transformer, either.
The actual pulse width can be set to determine
the AC voltage
generated.
Edward Ang wrote:
Wouldn't this only give you the RMS of the voltage
generated,
but the actual peak voltage would be a lot
different? This would
be very bad if you connect something with an input
cap rated at
200V (for 110Vac) because your Vdc (or peak) might
be above 200V.
I'm talking about a simple inverter that just chops
the DC into a square
wave, and uses phase control on the AC to limit the
RMS voltage to what
the load needs. For this to work, everything depends
on what you are
going to power with that inverter's AC.
Power supplies for electronic equipment rectify the
AC line, and mainly
care about the *peak* voltage. Phase control on a
square wave inverter
is not effective with such loads. You should not
power such devices from
an inverter that just controls pulse width.
Light bulbs, heaters, motors, transformers, and
other simple loads care
about the RMS value of the voltage, not the peak. So
you *can* power
such loads with a simple inverter that just controls
pulse width. For
example, 240vdc can be inverted into a 240vac square
wave, and then
phase controlled to become a 0v/+240v/0v/-240v
"modified sine wave". If
the total on-time is 25%, the RMS voltage is 120v,
and will power a 120v
light bulb or heater exactly the same as if it were
on 120vac. At 60hz,
this means:
0v from 0 - 6.25 msec
240v from 6.25 - 8.33 msec
0v from 8.33 - 14.58 msec
240v from 14.58 - 16.67 msec
An inductive load like a motor or transformer will
require a slightly
different ratio. The exact ratio depends on how
heavily loaded it is; a
light load it is mainly inductive and is more
towards 50% on-time.
Heavily loaded it moves toward a resistive load and
25% on-time.
Yes, the actual voltage applied to the device is
much higher. But
essentially all motors and transformers have enough
insulation to pass
UL hipot testing, which requires 1250 vac or more.
Actually, my goal is to get high power AC from my
'04
Prius. I have alrealy tapped into the 201.6V pack
with a pair of 10 gauge wires. The test data on
this
site (www.priups.com) shows that the voltage would
vary between about 210-230V if the battery is down
to
2 bars and the ICE kicks in to recharge it to 3
bars.
If scaled properly, this voltage range would
produce
110-120Vac or 220-240Vac without any adjustment.
This
is very tempting. (An EV would have a higher
ranges
of voltage swing that might need a variac if set
up
this way.) The idea of having an AT-PZEV 10kW
backup
generator in the garage is pretty exciting.
If you want to power any arbitrary load that you
might plug in, then you
need a "proper" inverter that delivers something
closer to a sine wave.
To make *any* load work, you will need a true
sinewave inverter.
--
"One doesn't discover new lands without consenting
to lose sight of the
shore for a very long time." -- Andre Gide
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377,
leeahart_at_earthlink.net
____________________________________________________
Start your day with Yahoo! - make it your home page
http://www.yahoo.com/r/hs
--- End Message ---
